Printing

Package captcha implements generation and verification of image and audio CAPTCHAs. A captcha solution is the sequence of digits 0-9 with the defined length. There are two captcha representations: image and audio. An image representation is a PNG-encoded image with the solution printed on it in such a way that makes it hard for computers to solve it using OCR. An audio representation is a WAVE-encoded (8 kHz unsigned 8-bit) sound with the spoken solution (currently in English, Russian, Chinese, and Japanese). To make it hard for computers to solve audio captcha, the voice that pronounces numbers has random speed and pitch, and there is a randomly generated background noise mixed into the sound. This package doesn't require external files or libraries to generate captcha representations; it is self-contained. To make captchas one-time, the package includes a memory storage that stores captcha ids, their solutions, and expiration time. Used captchas are removed from the store immediately after calling Verify or VerifyString, while unused captchas (user loaded a page with captcha, but didn't submit the form) are collected automatically after the predefined expiration time. Developers can also provide custom store (for example, which saves captcha ids and solutions in database) by implementing Store interface and registering the object with SetCustomStore. Captchas are created by calling New, which returns the captcha id. Their representations, though, are created on-the-fly by calling WriteImage or WriteAudio functions. Created representations are not stored anywhere, but subsequent calls to these functions with the same id will write the same captcha solution. Reload function will create a new different solution for the provided captcha, allowing users to "reload" captcha if they can't solve the displayed one without reloading the whole page. Verify and VerifyString are used to verify that the given solution is the right one for the given captcha id. Server provides an http.Handler which can serve image and audio representations of captchas automatically from the URL. It can also be used to reload captchas. Refer to Server function documentation for details, or take a look at the example in "capexample" subdirectory.

Rf refactors Go programs. Usage: Rf applies a script of refactoring commands to the package in the current directory. For example, to unexport a field in a struct by renaming it: By default, rf writes changes back to the disk. The -diff flag causes rf to print a diff of the intended changes instead. A script is a sequence of commands, one per line. Comments are introduced by # and extend to the end of the line. Commands may be broken across lines by ending all but the last with a trailing backslash (before any comment), as in: Commands that take { } blocks need not backslash-escape line breaks inside the braces, as in: Most commands take “code addresses” as arguments. Each code address identifies some code in a program. For illustration, consider this program, prog.go: The simplest code address is the name of a top-level declaration. In this program, those addresses are C, D, F, T, V, and VT. Adding .Name to an address selects a name within the earlier address, whether that's a function variable (F.who, F.msg), a struct field (T.Field), a method (T.M, T.P), or a variable's field (V.Value, V.thing, V.thing.Field, VT.Field). Another kind of code address is a Go source file, identified by a name ending in “.go”, as in “file.go”. If the file name contains a slash, as in “../dir/file.go”, the address identifies a file in the package in “../dir”. Another kind of code address is a Go package, identified by a path containing a slash but not ending in “.go”, as in “../dir” or “example.com/pkg”. A final kind of code address is a textual range in a function body or source file, identified by the syntax Ident:Range, where Ident identifies a file, function, or method and Range identifies a section of text within. The Range syntax is as used in the Acme and Sam text editors. The most common forms are the line range “N,M”, the byte range “#N,M”, and the regular expression range “/re1/,/re2/”. For example: See http://9p.io/sys/doc/sam/sam.html Table II for details on the syntax. The add command adds text to the source code. It takes as an argument the address after which the text should be added, followed by the text itself. The address may be a declaration, text range, file, or package. In all cases, the text is added immediately after the addressed location: after the declaration, after the text range, at the end of the file, or at the end of the first file in the package (considering the file names in lexical order). Examples: The cp command is like mv (see below) but doesn't delete the source and doesn't update any references. (UNIMPLEMENTED) The ex command applies rewrites based on example snippets. The arguments to ex are interpreted as Go code consisting of a sequence of imports and then a list of special “old -> new” rules. Each rule specifies that where ex finds a pattern matching old, it should replace the code with new. For example, to replace all log.Error calls with log.Panic: Declarations introduce typed pattern variables that can be used in rules. For example, to simplify certain needlessly complex uses of fmt.Sprintf: The inline command inlines uses of declared constants, functions, and types. Each use of the named declarations is replaced by the declaration's definition. If the -rm flag is given, inline removes the declarations as well. Examples: Given the declarations in the “Code addresses” section above, the first command replaces all uses of E with 2.718281828. The second replaces all uses of TAlias with T and then removes TAlias. UNIMPLEMENTED: Inlining of functions. The key command converts all struct literals for a list of types to keyed literals. Each address must identify a struct type. All literals of those struct types are updated to use the keyed form. Example: The mv command moves and renames code. When mv moves or renames old code, it also updates any references to use the new names or locations for the code. This includes updating other packages in the current module. In general, mv aims to act appropriately for any sensible combination of old and new address form. The rest of this section enumerates the specific cases that mv handles. item → renamed item Any named item can be renamed by specifying a destination that is the same code address with the final element changed. For example: In this form, the destination address must repeat the dot-separated elements leading up to the new name, changing only the final element. The repetition here distinguishes this form from other forms. var → var field A top-level variable can be moved to a new or existing field in a global variable of struct type. For example: method → func A method can be moved to a top-level function, removing the association with the receiver type. The receiver remains the first argument of the new function. For example: func → method A function can be moved to a method on the type of its first argument, assuming that type is defined in the same package where the function appears. For example: UNIMPLEMENTED. code text → new function A text range can be moved to a new function, leaving behind an appropriate call to that function. For example: code text → new method A text range can be moved to a new method, leaving behind an approriate call to that method. For example: TODO. UNIMPLEMENTED. declaration → file If the source is a top-level declaration (const, func, method, type, var) and the destination is a file, mv moves that declaration, along with any comments immediately preceding it, to the end of the destination file. For example: Naming a single item in a declaration block is taken to indicate wanting to move all items in the block. In the example from the “Code addresses” section, “mv C x.go” moves D as well. Any time a destination file must be created, mv initializes it with the header comments (those above the package declaration and any package doc) from the file the source code is being moved from. This heuristic is meant to copy header text like copyright notices. The file may be in a different package. As usual, mv updates references to the moved declaration to refer to its new location, inserting imports as needed. If the result is an import cycle, mv reports the cycle rather than attempt some kind of automatic (and likely wrong) fix. declaration → package If the source is a top-level declaration and the destination is a package, mv moves the declaration to the a file in the destination package with the same name as the one holding the source item. If the destination package does not exist, it will be created. file → file If the source and destination are both files, mv moves all code from the source file to the end of the destination file. For example: file → package If the source is a file and the destination is a package, mv moves all code from the source file to a file in the destination with the same base name. For example: package → file If the source is a package and the destination is a file, mv moves all code from the source package to the named file. For example: UNIMPLEMENTED. package → package If the source is a package and the destination is a file, mv moves all code from the source package to the destination package. from the source package to the named file. For example: UNIMPLEMENTED. many → file, many → package If the destination is a file or package, multiple sources can be listed. The mv command moves each source item in turn to the destination. The rm command removes code. Rm deletes the old code. All address forms are valid. When deleting a declaration, rm also deletes line comments immediately preceding it, up to a blank line. Rf is very very rough. Everything is subject to change, and it may break your programs.

Package wmi provides a WQL interface for WMI on Windows. Example code to print names of running processes:

Package log implements a simple logging package. It defines a type, Logger, with methods for formatting output. It also has a predefined 'standard' Logger accessible through helper functions Print[f|ln], Fatal[f|ln], and Panic[f|ln], which are easier to use than creating a Logger manually. That logger writes to standard error and prints the date and time of each logged message. Every log message is output on a separate line: if the message being printed does not end in a newline, the logger will add one. The Fatal functions call os.Exit(1) after writing the log message. The Panic functions call panic after writing the log message.

Package ebpf is a toolkit for working with eBPF programs. eBPF programs are small snippets of code which are executed directly in a VM in the Linux kernel, which makes them very fast and flexible. Many Linux subsystems now accept eBPF programs. This makes it possible to implement highly application specific logic inside the kernel, without having to modify the actual kernel itself. This package is designed for long-running processes which want to use eBPF to implement part of their application logic. It has no run-time dependencies outside of the library and the Linux kernel itself. eBPF code should be compiled ahead of time using clang, and shipped with your application as any other resource. This package doesn't include code required to attach eBPF to Linux subsystems, since this varies per subsystem. ExampleMarshaler shows how to use custom encoding with map methods. ExampleExtractDistance shows how to attach an eBPF socket filter to extract the network distance of an IP host. Example_program demonstrates how to attach an eBPF program to a tracepoint. The program will be attached to the sys_enter_open syscall and print out the integer 123 everytime the sycall is used. ExampleSocketELF demonstrates how to load an eBPF program from an ELF, and attach it to a raw socket.

Package assert provides developer a way to assert expression and output useful contextual information automatically when a case fails. With this package, we can focus on writing test code without worrying about how to print lots of verbose debug information for debug. See project page for more samples. https://github.com/huandu/go-assert

Package serial is a cross-platform serial library for the go language. It is possible to get the list of available serial ports with the GetPortsList function: The serial port can be opened with the Open function: The Open function needs a "mode" parameter that specifies the configuration options for the serial port. If not specified the default options are 9600_N81, in the example above only the speed is changed so the port is opened using 115200_N81. The following snippets shows how to declare a configuration for 57600_E71: The configuration can be changed at any time with the SetMode function: The port object implements the io.ReadWriteCloser interface, so we can use the usual Read, Write and Close functions to send and receive data from the serial port: If a port is a virtual USB-CDC serial port (for example an USB-to-RS232 cable or a microcontroller development board) is possible to retrieve the USB metadata, like VID/PID or USB Serial Number, with the GetDetailedPortsList function in the enumerator package: for details on USB port enumeration see the documentation of the specific package. This library tries to avoid the use of the "C" package (and consequently the need of cgo) to simplify cross compiling. Unfortunately the USB enumeration package for darwin (MacOSX) requires cgo to access the IOKit framework. This means that if you need USB enumeration on darwin you're forced to use cgo. This example prints the list of serial ports and use the first one to send a string "10,20,30" and prints the response on the screen.

Package err2 is error handling solution including three main functionality: The err2 package drives programmers to focus on error handling rather than checking errors. We think that checks should be so easy that we never forget them. The CopyFile example shows how it works: The github.com/lainio/err2/try package provides convenient helpers to check the errors. For example, instead of we can write Note that try.To functions are as fast as if err != nil statements. Please see the github.com/lainio/err2/try package documentation for more information about the error checks. err2 offers optional stack tracing. And yes, it's fully automatic. Just call at the beginning your app, e.g. main function, or set the tracers programmatically (before flag.Parse if you are using that): Note that since Catch's default mode is to recover from panics, it's a good practice still print their stack trace. The panic tracer's default values is os.Stderr. The default error tracer is nil. Note that both panic and error traces are optimized by err2 package. That means that the head of the stack trace isn't the panic function, but an actual line that caused it. It works for all three categories: The last two types are handled as panics in the error handling functions given to Handle and Catch. Same err2 capablities support automatic logging like the Catch and [try.Result.Logf] functions. To be able to tune up how logging behaves we offer a tracer API: The err2 package supports Go's flags. All you need to do is to call flag.Parse. And the following flags are supported (="default-value"): Note that you have called SetErrorTracer and others, before you call flag.Parse. This allows you set the defaults according your app's need and allow end-user change them during the runtime. Package err2 relies on declarative control structures to achieve error and panic safety. In every function which uses err2 or try package for error-checking has to have at least one declarative error handler if it returns error value. If there are no error handlers and error occurs it panics. We think that panicking for the errors is much better than not checking errors at all. Nevertheless, if the call stack includes any err2 error handlers like Handle the error is handled where the handler is saved to defer-stack. (defer is not lexically scoped) err2 includes many examples to play with like previous CopyFile. Please see them for more information.

The gotype command does syntactic and semantic analysis of Go files and packages like the front-end of a Go compiler. Errors are reported if the analysis fails; otherwise gotype is quiet (unless -v is set). Without a list of paths, gotype reads from standard input, which must provide a single Go source file defining a complete package. If a single path is specified that is a directory, gotype checks the Go files in that directory; they must all belong to the same package. Otherwise, each path must be the filename of Go file belonging to the same package. Usage: The flags are: Debugging flags: Examples: To check the files a.go, b.go, and c.go: To check an entire package in the directory dir and print the processed files: To check an entire package including tests in the local directory: To verify the output of a pipe:

This is the official Go SDK for Oracle Cloud Infrastructure Refer to https://github.com/oracle/oci-go-sdk/blob/master/README.md#installing for installation instructions. Refer to https://github.com/oracle/oci-go-sdk/blob/master/README.md#configuring for configuration instructions. The following example shows how to get started with the SDK. The example belows creates an identityClient struct with the default configuration. It then utilizes the identityClient to list availability domains and prints them out to stdout More examples can be found in the SDK Github repo: https://github.com/oracle/oci-go-sdk/tree/master/example Optional fields are represented with the `mandatory:"false"` tag on input structs. The SDK will omit all optional fields that are nil when making requests. In the case of enum-type fields, the SDK will omit fields whose value is an empty string. The SDK uses pointers for primitive types in many input structs. To aid in the construction of such structs, the SDK provides functions that return a pointer for a given value. For example: The SDK exposes functionality that allows the user to customize any http request before is sent to the service. You can do so by setting the `Interceptor` field in any of the `Client` structs. For example: The Interceptor closure gets called before the signing process, thus any changes done to the request will be properly signed and submitted to the service. The SDK exposes a stand-alone signer that can be used to signing custom requests. Related code can be found here: https://github.com/oracle/oci-go-sdk/blob/master/common/http_signer.go. The example below shows how to create a default signer. The signer also allows more granular control on the headers used for signing. For example: You can combine a custom signer with the exposed clients in the SDK. This allows you to add custom signed headers to the request. Following is an example: Bear in mind that some services have a white list of headers that it expects to be signed. Therefore, adding an arbitrary header can result in authentications errors. To see a runnable example, see https://github.com/oracle/oci-go-sdk/blob/master/example/example_identity_test.go For more information on the signing algorithm refer to: https://docs.cloud.oracle.com/Content/API/Concepts/signingrequests.htm Some operations accept or return polymorphic JSON objects. The SDK models such objects as interfaces. Further the SDK provides structs that implement such interfaces. Thus, for all operations that expect interfaces as input, pass the struct in the SDK that satisfies such interface. For example: In the case of a polymorphic response you can type assert the interface to the expected type. For example: An example of polymorphic JSON request handling can be found here: https://github.com/oracle/oci-go-sdk/blob/master/example/example_core_test.go#L63 When calling a list operation, the operation will retrieve a page of results. To retrieve more data, call the list operation again, passing in the value of the most recent response's OpcNextPage as the value of Page in the next list operation call. When there is no more data the OpcNextPage field will be nil. An example of pagination using this logic can be found here: https://github.com/oracle/oci-go-sdk/blob/master/example/example_core_pagination_test.go The SDK has a built-in logging mechanism used internally. The internal logging logic is used to record the raw http requests, responses and potential errors when (un)marshalling request and responses. Built-in logging in the SDK is controlled via the environment variable "OCI_GO_SDK_DEBUG" and its contents. The below are possible values for the "OCI_GO_SDK_DEBUG" variable 1. "info" or "i" enables all info logging messages 2. "debug" or "d" enables all debug and info logging messages 3. "verbose" or "v" or "1" enables all verbose, debug and info logging messages 4. "null" turns all logging messages off. If the value of the environment variable does not match any of the above then default logging level is "info". If the environment variable is not present then no logging messages are emitted. The default destination for logging is Stderr and if you want to output log to a file you can set via environment variable "OCI_GO_SDK_LOG_OUTPUT_MODE". The below are possible values 1. "file" or "f" enables all logging output saved to file 2. "combine" or "c" enables all logging output to both stderr and file You can also customize the log file location and name via "OCI_GO_SDK_LOG_FILE" environment variable, the value should be the path to a specific file If this environment variable is not present, the default location will be the project root path Sometimes you may need to wait until an attribute of a resource, such as an instance or a VCN, reaches a certain state. An example of this would be launching an instance and then waiting for the instance to become available, or waiting until a subnet in a VCN has been terminated. You might also want to retry the same operation again if there's network issue etc... This can be accomplished by using the RequestMetadata.RetryPolicy(request level configuration), alternatively, global(all services) or client level RetryPolicy configration is also possible. You can find the examples here: https://github.com/oracle/oci-go-sdk/blob/master/example/example_retry_test.go If you are trying to make a PUT/POST API call with binary request body, please make sure the binary request body is resettable, which means the request body should inherit Seeker interface. The Retry behavior Precedence (Highest to lowest) is defined as below:- The OCI Go SDK defines a default retry policy that retries on the errors suitable for retries (see https://docs.oracle.com/en-us/iaas/Content/API/References/apierrors.htm), for a recommended period of time (up to 7 attempts spread out over at most approximately 1.5 minutes). The default retry policy is defined by : Default Retry-able Errors Below is the list of default retry-able errors for which retry attempts should be made. The following errors should be retried (with backoff). HTTP Code Customer-facing Error Code Apart from the above errors, retries should also be attempted in the following Client Side errors : 1. HTTP Connection timeout 2. Request Connection Errors 3. Request Exceptions 4. Other timeouts (like Read Timeout) The above errors can be avoided through retrying and hence, are classified as the default retry-able errors. Additionally, retries should also be made for Circuit Breaker exceptions (Exceptions raised by Circuit Breaker in an open state) Default Termination Strategy The termination strategy defines when SDKs should stop attempting to retry. In other words, it's the deadline for retries. The OCI SDKs should stop retrying the operation after 7 retry attempts. This means the SDKs will have retried for ~98 seconds or ~1.5 minutes have elapsed due to total delays. SDKs will make a total of 8 attempts. (1 initial request + 7 retries) Default Delay Strategy Default Delay Strategy - The delay strategy defines the amount of time to wait between each of the retry attempts. The default delay strategy chosen for the SDK – Exponential backoff with jitter, using: 1. The base time to use in retry calculations will be 1 second 2. An exponent of 2. When calculating the next retry time, the SDK will raise this to the power of the number of attempts 3. A maximum wait time between calls of 30 seconds (Capped) 4. Added jitter value between 0-1000 milliseconds to spread out the requests Configure and use default retry policy You can set this retry policy for a single request: or for all requests made by a client: or for all requests made by all clients: or setting default retry via environment varaible, which is a global switch for all services: Some services enable retry for operations by default, this can be overridden using any alternatives mentioned above. To know which service operations have retries enabled by default, look at the operation's description in the SDK - it will say whether that it has retries enabled by default Some resources may have to be replicated across regions and are only eventually consistent. That means the request to create, update, or delete the resource succeeded, but the resource is not available everywhere immediately. Creating, updating, or deleting any resource in the Identity service is affected by eventual consistency, and doing so may cause other operations in other services to fail until the Identity resource has been replicated. For example, the request to CreateTag in the Identity service in the home region succeeds, but immediately using that created tag in another region in a request to LaunchInstance in the Compute service may fail. If you are creating, updating, or deleting resources in the Identity service, we recommend using an eventually consistent retry policy for any service you access. The default retry policy already deals with eventual consistency. Example: This retry policy will use a different strategy if an eventually consistent change was made in the recent past (called the "eventually consistent window", currently defined to be 4 minutes after the eventually consistent change). This special retry policy for eventual consistency will: 1. make up to 9 attempts (including the initial attempt); if an attempt is successful, no more attempts will be made 2. retry at most until (a) approximately the end of the eventually consistent window or (b) the end of the default retry period of about 1.5 minutes, whichever is farther in the future; if an attempt is successful, no more attempts will be made, and the OCI Go SDK will not wait any longer 3. retry on the error codes 400-RelatedResourceNotAuthorizedOrNotFound, 404-NotAuthorizedOrNotFound, and 409-NotAuthorizedOrResourceAlreadyExists, for which the default retry policy does not retry, in addition to the errors the default retry policy retries on (see https://docs.oracle.com/en-us/iaas/Content/API/References/apierrors.htm) If there were no eventually consistent actions within the recent past, then this special retry strategy is not used. If you want a retry policy that does not handle eventual consistency in a special way, for example because you retry on all error responses, you can use DefaultRetryPolicyWithoutEventualConsistency or NewRetryPolicyWithOptions with the common.ReplaceWithValuesFromRetryPolicy(common.DefaultRetryPolicyWithoutEventualConsistency()) option: The NewRetryPolicy function also creates a retry policy without eventual consistency. Circuit Breaker can prevent an application repeatedly trying to execute an operation that is likely to fail, allowing it to continue without waiting for the fault to be rectified or wasting CPU cycles, of course, it also enables an application to detect whether the fault has been resolved. If the problem appears to have been rectified, the application can attempt to invoke the operation. Go SDK intergrates sony/gobreaker solution, wraps in a circuit breaker object, which monitors for failures. Once the failures reach a certain threshold, the circuit breaker trips, and all further calls to the circuit breaker return with an error, this also saves the service from being overwhelmed with network calls in case of an outage. Circuit Breaker Configuration Definitions 1. Failure Rate Threshold - The state of the CircuitBreaker changes from CLOSED to OPEN when the failure rate is equal or greater than a configurable threshold. For example when more than 50% of the recorded calls have failed. 2. Reset Timeout - The timeout after which an open circuit breaker will attempt a request if a request is made 3. Failure Exceptions - The list of Exceptions that will be regarded as failures for the circuit. 4. Minimum number of calls/ Volume threshold - Configures the minimum number of calls which are required (per sliding window period) before the CircuitBreaker can calculate the error rate. 1. Failure Rate Threshold - 80% - This means when 80% of the requests calculated for a time window of 120 seconds have failed then the circuit will transition from closed to open. 2. Minimum number of calls/ Volume threshold - A value of 10, for the above defined time window of 120 seconds. 3. Reset Timeout - 30 seconds to wait before setting the breaker to halfOpen state, and trying the action again. 4. Failure Exceptions - The failures for the circuit will only be recorded for the retryable/transient exceptions. This means only the following exceptions will be regarded as failure for the circuit. HTTP Code Customer-facing Error Code Apart from the above, the following client side exceptions will also be treated as a failure for the circuit : 1. HTTP Connection timeout 2. Request Connection Errors 3. Request Exceptions 4. Other timeouts (like Read Timeout) Go SDK enable circuit breaker with default configuration for most of the service clients, if you don't want to enable the solution, can disable the functionality before your application running Go SDK also supports customize Circuit Breaker with specified configurations. You can find the examples here: https://github.com/oracle/oci-go-sdk/blob/master/example/example_circuitbreaker_test.go To know which service clients have circuit breakers enabled, look at the service client's description in the SDK - it will say whether that it has circuit breakers enabled by default The GO SDK uses the net/http package to make calls to OCI services. If your environment requires you to use a proxy server for outgoing HTTP requests then you can set this up in the following ways: 1. Configuring environment variable as described here https://golang.org/pkg/net/http/#ProxyFromEnvironment 2. Modifying the underlying Transport struct for a service client In order to modify the underlying Transport struct in HttpClient, you can do something similar to (sample code for audit service client): The Object Storage service supports multipart uploads to make large object uploads easier by splitting the large object into parts. The Go SDK supports raw multipart upload operations for advanced use cases, as well as a higher level upload class that uses the multipart upload APIs. For links to the APIs used for multipart upload operations, see Managing Multipart Uploads (https://docs.cloud.oracle.com/iaas/Content/Object/Tasks/usingmultipartuploads.htm). Higher level multipart uploads are implemented using the UploadManager, which will: split a large object into parts for you, upload the parts in parallel, and then recombine and commit the parts as a single object in storage. This code sample shows how to use the UploadManager to automatically split an object into parts for upload to simplify interaction with the Object Storage service: https://github.com/oracle/oci-go-sdk/blob/master/example/example_objectstorage_test.go Some response fields are enum-typed. In the future, individual services may return values not covered by existing enums for that field. To address this possibility, every enum-type response field is a modeled as a type that supports any string. Thus if a service returns a value that is not recognized by your version of the SDK, then the response field will be set to this value. When individual services return a polymorphic JSON response not available as a concrete struct, the SDK will return an implementation that only satisfies the interface modeling the polymorphic JSON response. If you are using a version of the SDK released prior to the announcement of a new region, you may need to use a workaround to reach it, depending on whether the region is in the oraclecloud.com realm. A region is a localized geographic area. For more information on regions and how to identify them, see Regions and Availability Domains(https://docs.cloud.oracle.com/iaas/Content/General/Concepts/regions.htm). A realm is a set of regions that share entities. You can identify your realm by looking at the domain name at the end of the network address. For example, the realm for xyz.abc.123.oraclecloud.com is oraclecloud.com. oraclecloud.com Realm: For regions in the oraclecloud.com realm, even if common.Region does not contain the new region, the forward compatibility of the SDK can automatically handle it. You can pass new region names just as you would pass ones that are already defined. For more information on passing region names in the configuration, see Configuring (https://github.com/oracle/oci-go-sdk/blob/master/README.md#configuring). For details on common.Region, see (https://github.com/oracle/oci-go-sdk/blob/master/common/common.go). Other Realms: For regions in realms other than oraclecloud.com, you can use the following workarounds to reach new regions with earlier versions of the SDK. NOTE: Be sure to supply the appropriate endpoints for your region. You can overwrite the target host with client.Host: If you are authenticating via instance principals, you can set the authentication endpoint in an environment variable: Got a fix for a bug, or a new feature you'd like to contribute? The SDK is open source and accepting pull requests on GitHub https://github.com/oracle/oci-go-sdk Licensing information available at: https://github.com/oracle/oci-go-sdk/blob/master/LICENSE.txt To be notified when a new version of the Go SDK is released, subscribe to the following feed: https://github.com/oracle/oci-go-sdk/releases.atom Please refer to this link: https://github.com/oracle/oci-go-sdk#help

This is the official Go SDK for Oracle Cloud Infrastructure Refer to https://github.com/oracle/oci-go-sdk/blob/master/README.md#installing for installation instructions. Refer to https://github.com/oracle/oci-go-sdk/blob/master/README.md#configuring for configuration instructions. The following example shows how to get started with the SDK. The example belows creates an identityClient struct with the default configuration. It then utilizes the identityClient to list availability domains and prints them out to stdout More examples can be found in the SDK Github repo: https://github.com/oracle/oci-go-sdk/tree/master/example Optional fields are represented with the `mandatory:"false"` tag on input structs. The SDK will omit all optional fields that are nil when making requests. In the case of enum-type fields, the SDK will omit fields whose value is an empty string. The SDK uses pointers for primitive types in many input structs. To aid in the construction of such structs, the SDK provides functions that return a pointer for a given value. For example: The SDK exposes functionality that allows the user to customize any http request before is sent to the service. You can do so by setting the `Interceptor` field in any of the `Client` structs. For example: The Interceptor closure gets called before the signing process, thus any changes done to the request will be properly signed and submitted to the service. The SDK exposes a stand-alone signer that can be used to signing custom requests. Related code can be found here: https://github.com/oracle/oci-go-sdk/blob/master/common/http_signer.go. The example below shows how to create a default signer. The signer also allows more granular control on the headers used for signing. For example: You can combine a custom signer with the exposed clients in the SDK. This allows you to add custom signed headers to the request. Following is an example: Bear in mind that some services have a white list of headers that it expects to be signed. Therefore, adding an arbitrary header can result in authentications errors. To see a runnable example, see https://github.com/oracle/oci-go-sdk/blob/master/example/example_identity_test.go For more information on the signing algorithm refer to: https://docs.cloud.oracle.com/Content/API/Concepts/signingrequests.htm Some operations accept or return polymorphic JSON objects. The SDK models such objects as interfaces. Further the SDK provides structs that implement such interfaces. Thus, for all operations that expect interfaces as input, pass the struct in the SDK that satisfies such interface. For example: In the case of a polymorphic response you can type assert the interface to the expected type. For example: An example of polymorphic JSON request handling can be found here: https://github.com/oracle/oci-go-sdk/blob/master/example/example_core_test.go#L63 When calling a list operation, the operation will retrieve a page of results. To retrieve more data, call the list operation again, passing in the value of the most recent response's OpcNextPage as the value of Page in the next list operation call. When there is no more data the OpcNextPage field will be nil. An example of pagination using this logic can be found here: https://github.com/oracle/oci-go-sdk/blob/master/example/example_core_pagination_test.go The SDK has a built-in logging mechanism used internally. The internal logging logic is used to record the raw http requests, responses and potential errors when (un)marshalling request and responses. Built-in logging in the SDK is controlled via the environment variable "OCI_GO_SDK_DEBUG" and its contents. The below are possible values for the "OCI_GO_SDK_DEBUG" variable 1. "info" or "i" enables all info logging messages 2. "debug" or "d" enables all debug and info logging messages 3. "verbose" or "v" or "1" enables all verbose, debug and info logging messages 4. "null" turns all logging messages off. If the value of the environment variable does not match any of the above then default logging level is "info". If the environment variable is not present then no logging messages are emitted. The default destination for logging is Stderr and if you want to output log to a file you can set via environment variable "OCI_GO_SDK_LOG_OUTPUT_MODE". The below are possible values 1. "file" or "f" enables all logging output saved to file 2. "combine" or "c" enables all logging output to both stderr and file You can also customize the log file location and name via "OCI_GO_SDK_LOG_FILE" environment variable, the value should be the path to a specific file If this environment variable is not present, the default location will be the project root path Sometimes you may need to wait until an attribute of a resource, such as an instance or a VCN, reaches a certain state. An example of this would be launching an instance and then waiting for the instance to become available, or waiting until a subnet in a VCN has been terminated. You might also want to retry the same operation again if there's network issue etc... This can be accomplished by using the RequestMetadata.RetryPolicy. You can find the examples here: https://github.com/oracle/oci-go-sdk/blob/master/example/example_retry_test.go If you are trying to make a PUT/POST API call with binary request body, please make sure the binary request body is resettable, which means the request body should inherit Seeker interface. The GO SDK uses the net/http package to make calls to OCI services. If your environment requires you to use a proxy server for outgoing HTTP requests then you can set this up in the following ways: 1. Configuring environment variable as described here https://golang.org/pkg/net/http/#ProxyFromEnvironment 2. Modifying the underlying Transport struct for a service client In order to modify the underlying Transport struct in HttpClient, you can do something similar to (sample code for audit service client): The Object Storage service supports multipart uploads to make large object uploads easier by splitting the large object into parts. The Go SDK supports raw multipart upload operations for advanced use cases, as well as a higher level upload class that uses the multipart upload APIs. For links to the APIs used for multipart upload operations, see Managing Multipart Uploads (https://docs.cloud.oracle.com/iaas/Content/Object/Tasks/usingmultipartuploads.htm). Higher level multipart uploads are implemented using the UploadManager, which will: split a large object into parts for you, upload the parts in parallel, and then recombine and commit the parts as a single object in storage. This code sample shows how to use the UploadManager to automatically split an object into parts for upload to simplify interaction with the Object Storage service: https://github.com/oracle/oci-go-sdk/blob/master/example/example_objectstorage_test.go Some response fields are enum-typed. In the future, individual services may return values not covered by existing enums for that field. To address this possibility, every enum-type response field is a modeled as a type that supports any string. Thus if a service returns a value that is not recognized by your version of the SDK, then the response field will be set to this value. When individual services return a polymorphic JSON response not available as a concrete struct, the SDK will return an implementation that only satisfies the interface modeling the polymorphic JSON response. If you are using a version of the SDK released prior to the announcement of a new region, you may need to use a workaround to reach it, depending on whether the region is in the oraclecloud.com realm. A region is a localized geographic area. For more information on regions and how to identify them, see Regions and Availability Domains(https://docs.cloud.oracle.com/iaas/Content/General/Concepts/regions.htm). A realm is a set of regions that share entities. You can identify your realm by looking at the domain name at the end of the network address. For example, the realm for xyz.abc.123.oraclecloud.com is oraclecloud.com. oraclecloud.com Realm: For regions in the oraclecloud.com realm, even if common.Region does not contain the new region, the forward compatibility of the SDK can automatically handle it. You can pass new region names just as you would pass ones that are already defined. For more information on passing region names in the configuration, see Configuring (https://github.com/oracle/oci-go-sdk/blob/master/README.md#configuring). For details on common.Region, see (https://github.com/oracle/oci-go-sdk/blob/master/common/common.go). Other Realms: For regions in realms other than oraclecloud.com, you can use the following workarounds to reach new regions with earlier versions of the SDK. NOTE: Be sure to supply the appropriate endpoints for your region. You can overwrite the target host with client.Host: If you are authenticating via instance principals, you can set the authentication endpoint in an environment variable: Got a fix for a bug, or a new feature you'd like to contribute? The SDK is open source and accepting pull requests on GitHub https://github.com/oracle/oci-go-sdk Licensing information available at: https://github.com/oracle/oci-go-sdk/blob/master/LICENSE.txt To be notified when a new version of the Go SDK is released, subscribe to the following feed: https://github.com/oracle/oci-go-sdk/releases.atom Please refer to this link: https://github.com/oracle/oci-go-sdk#help

This is the official Go SDK for Oracle Cloud Infrastructure Refer to https://github.com/oracle/oci-go-sdk/blob/master/README.md#installing for installation instructions. Refer to https://github.com/oracle/oci-go-sdk/blob/master/README.md#configuring for configuration instructions. The following example shows how to get started with the SDK. The example belows creates an identityClient struct with the default configuration. It then utilizes the identityClient to list availability domains and prints them out to stdout More examples can be found in the SDK Github repo: https://github.com/oracle/oci-go-sdk/tree/master/example Optional fields are represented with the `mandatory:"false"` tag on input structs. The SDK will omit all optional fields that are nil when making requests. In the case of enum-type fields, the SDK will omit fields whose value is an empty string. The SDK uses pointers for primitive types in many input structs. To aid in the construction of such structs, the SDK provides functions that return a pointer for a given value. For example: The SDK exposes functionality that allows the user to customize any http request before is sent to the service. You can do so by setting the `Interceptor` field in any of the `Client` structs. For example: The Interceptor closure gets called before the signing process, thus any changes done to the request will be properly signed and submitted to the service. The SDK exposes a stand-alone signer that can be used to signing custom requests. Related code can be found here: https://github.com/oracle/oci-go-sdk/blob/master/common/http_signer.go. The example below shows how to create a default signer. The signer also allows more granular control on the headers used for signing. For example: You can combine a custom signer with the exposed clients in the SDK. This allows you to add custom signed headers to the request. Following is an example: Bear in mind that some services have a white list of headers that it expects to be signed. Therefore, adding an arbitrary header can result in authentications errors. To see a runnable example, see https://github.com/oracle/oci-go-sdk/blob/master/example/example_identity_test.go For more information on the signing algorithm refer to: https://docs.cloud.oracle.com/Content/API/Concepts/signingrequests.htm Some operations accept or return polymorphic JSON objects. The SDK models such objects as interfaces. Further the SDK provides structs that implement such interfaces. Thus, for all operations that expect interfaces as input, pass the struct in the SDK that satisfies such interface. For example: In the case of a polymorphic response you can type assert the interface to the expected type. For example: An example of polymorphic JSON request handling can be found here: https://github.com/oracle/oci-go-sdk/blob/master/example/example_core_test.go#L63 When calling a list operation, the operation will retrieve a page of results. To retrieve more data, call the list operation again, passing in the value of the most recent response's OpcNextPage as the value of Page in the next list operation call. When there is no more data the OpcNextPage field will be nil. An example of pagination using this logic can be found here: https://github.com/oracle/oci-go-sdk/blob/master/example/example_core_pagination_test.go The SDK has a built-in logging mechanism used internally. The internal logging logic is used to record the raw http requests, responses and potential errors when (un)marshalling request and responses. Built-in logging in the SDK is controlled via the environment variable "OCI_GO_SDK_DEBUG" and its contents. The below are possible values for the "OCI_GO_SDK_DEBUG" variable 1. "info" or "i" enables all info logging messages 2. "debug" or "d" enables all debug and info logging messages 3. "verbose" or "v" or "1" enables all verbose, debug and info logging messages 4. "null" turns all logging messages off. If the value of the environment variable does not match any of the above then default logging level is "info". If the environment variable is not present then no logging messages are emitted. The default destination for logging is Stderr and if you want to output log to a file you can set via environment variable "OCI_GO_SDK_LOG_OUTPUT_MODE". The below are possible values 1. "file" or "f" enables all logging output saved to file 2. "combine" or "c" enables all logging output to both stderr and file You can also customize the log file location and name via "OCI_GO_SDK_LOG_FILE" environment variable, the value should be the path to a specific file If this environment variable is not present, the default location will be the project root path Sometimes you may need to wait until an attribute of a resource, such as an instance or a VCN, reaches a certain state. An example of this would be launching an instance and then waiting for the instance to become available, or waiting until a subnet in a VCN has been terminated. You might also want to retry the same operation again if there's network issue etc... This can be accomplished by using the RequestMetadata.RetryPolicy. You can find the examples here: https://github.com/oracle/oci-go-sdk/blob/master/example/example_retry_test.go The GO SDK uses the net/http package to make calls to OCI services. If your environment requires you to use a proxy server for outgoing HTTP requests then you can set this up in the following ways: 1. Configuring environment variable as described here https://golang.org/pkg/net/http/#ProxyFromEnvironment 2. Modifying the underlying Transport struct for a service client In order to modify the underlying Transport struct in HttpClient, you can do something similar to (sample code for audit service client): The Object Storage service supports multipart uploads to make large object uploads easier by splitting the large object into parts. The Go SDK supports raw multipart upload operations for advanced use cases, as well as a higher level upload class that uses the multipart upload APIs. For links to the APIs used for multipart upload operations, see Managing Multipart Uploads (https://docs.cloud.oracle.com/iaas/Content/Object/Tasks/usingmultipartuploads.htm). Higher level multipart uploads are implemented using the UploadManager, which will: split a large object into parts for you, upload the parts in parallel, and then recombine and commit the parts as a single object in storage. This code sample shows how to use the UploadManager to automatically split an object into parts for upload to simplify interaction with the Object Storage service: https://github.com/oracle/oci-go-sdk/blob/master/example/example_objectstorage_test.go Some response fields are enum-typed. In the future, individual services may return values not covered by existing enums for that field. To address this possibility, every enum-type response field is a modeled as a type that supports any string. Thus if a service returns a value that is not recognized by your version of the SDK, then the response field will be set to this value. When individual services return a polymorphic JSON response not available as a concrete struct, the SDK will return an implementation that only satisfies the interface modeling the polymorphic JSON response. If you are using a version of the SDK released prior to the announcement of a new region, you may need to use a workaround to reach it, depending on whether the region is in the oraclecloud.com realm. A region is a localized geographic area. For more information on regions and how to identify them, see Regions and Availability Domains(https://docs.cloud.oracle.com/iaas/Content/General/Concepts/regions.htm). A realm is a set of regions that share entities. You can identify your realm by looking at the domain name at the end of the network address. For example, the realm for xyz.abc.123.oraclecloud.com is oraclecloud.com. oraclecloud.com Realm: For regions in the oraclecloud.com realm, even if common.Region does not contain the new region, the forward compatibility of the SDK can automatically handle it. You can pass new region names just as you would pass ones that are already defined. For more information on passing region names in the configuration, see Configuring (https://github.com/oracle/oci-go-sdk/blob/master/README.md#configuring). For details on common.Region, see (https://github.com/oracle/oci-go-sdk/blob/master/common/common.go). Other Realms: For regions in realms other than oraclecloud.com, you can use the following workarounds to reach new regions with earlier versions of the SDK. NOTE: Be sure to supply the appropriate endpoints for your region. You can overwrite the target host with client.Host: If you are authenticating via instance principals, you can set the authentication endpoint in an environment variable: Got a fix for a bug, or a new feature you'd like to contribute? The SDK is open source and accepting pull requests on GitHub https://github.com/oracle/oci-go-sdk Licensing information available at: https://github.com/oracle/oci-go-sdk/blob/master/LICENSE.txt To be notified when a new version of the Go SDK is released, subscribe to the following feed: https://github.com/oracle/oci-go-sdk/releases.atom Please refer to this link: https://github.com/oracle/oci-go-sdk#help

Package jsonrpc2 is a complete and strictly conforming implementation of the JSON-RPC 2.0 protocol for both clients and servers. The full specification can be found at https://www.jsonrpc.org. The simplest way to make a JSON-RPC 2.0 request is to use the provided Client.Request. For clients that do not wish to use the provided Client, the Request and Response types can be used directly. Servers define their own MethodFuncs and associate them with a name in a MethodMap that is passed to HTTPRequestHandler() to return a corresponding http.HandlerFunc. See HTTPRequestHandler for more details. This example makes all of the calls from the examples in the JSON-RPC 2.0 specification and prints them in a similar format.

Package cgi implements the common gateway interface (CGI) for Caddy, a modern, full-featured, easy-to-use web server. This plugin lets you generate dynamic content on your website by means of command line scripts. To collect information about the inbound HTTP request, your script examines certain environment variables such as PATH_INFO and QUERY_STRING. Then, to return a dynamically generated web page to the client, your script simply writes content to standard output. In the case of POST requests, your script reads additional inbound content from standard input. The advantage of CGI is that you do not need to fuss with server startup and persistence, long term memory management, sockets, and crash recovery. Your script is called when a request matches one of the patterns that you specify in your Caddyfile. As soon as your script completes its response, it terminates. This simplicity makes CGI a perfect complement to the straightforward operation and configuration of Caddy. The benefits of Caddy, including HTTPS by default, basic access authentication, and lots of middleware options extend easily to your CGI scripts. CGI has some disadvantages. For one, Caddy needs to start a new process for each request. This can adversely impact performance and, if resources are shared between CGI applications, may require the use of some interprocess synchronization mechanism such as a file lock. Your server’s responsiveness could in some circumstances be affected, such as when your web server is hit with very high demand, when your script’s dependencies require a long startup, or when concurrently running scripts take a long time to respond. However, in many cases, such as using a pre-compiled CGI application like fossil or a Lua script, the impact will generally be insignificant. Another restriction of CGI is that scripts will be run with the same permissions as Caddy itself. This can sometimes be less than ideal, for example when your script needs to read or write files associated with a different owner. Serving dynamic content exposes your server to more potential threats than serving static pages. There are a number of considerations of which you should be aware when using CGI applications. CGI SCRIPTS SHOULD BE LOCATED OUTSIDE OF CADDY’S DOCUMENT ROOT. Otherwise, an inadvertent misconfiguration could result in Caddy delivering the script as an ordinary static resource. At best, this could merely confuse the site visitor. At worst, it could expose sensitive internal information that should not leave the server. MISTRUST THE CONTENTS OF PATH_INFO, QUERY_STRING AND STANDARD INPUT. Most of the environment variables available to your CGI program are inherently safe because they originate with Caddy and cannot be modified by external users. This is not the case with PATH_INFO, QUERY_STRING and, in the case of POST actions, the contents of standard input. Be sure to validate and sanitize all inbound content. If you use a CGI library or framework to process your scripts, make sure you understand its limitations. An error in a CGI application is generally handled within the application itself and reported in the headers it returns. Additionally, if the Caddy errors directive is enabled, any content the application writes to its standard error stream will be written to the error log. This can be useful to diagnose problems with the execution of the CGI application. Your CGI application can be executed directly or indirectly. In the direct case, the application can be a compiled native executable or it can be a shell script that contains as its first line a shebang that identifies the interpreter to which the file’s name should be passed. Caddy must have permission to execute the application. On Posix systems this will mean making sure the application’s ownership and permission bits are set appropriately; on Windows, this may involve properly setting up the filename extension association. In the indirect case, the name of the CGI script is passed to an interpreter such as lua, perl or python. The basic cgi directive lets you associate a single pattern with a particular script. The directive can be repeated any reasonable number of times. Here is the basic syntax: For example: When a request such as https://example.com/report or https://example.com/report/weekly arrives, the cgi middleware will detect the match and invoke the script named /usr/local/cgi-bin/report. The current working directory will be the same as Caddy itself. Here, it is assumed that the script is self-contained, for example a pre-compiled CGI application or a shell script. Here is an example of a standalone script, similar to one used in the cgi plugin’s test suite: The environment variables PATH_INFO and QUERY_STRING are populated and passed to the script automatically. There are a number of other standard CGI variables included that are described below. If you need to pass any special environment variables or allow any environment variables that are part of Caddy’s process to pass to your script, you will need to use the advanced directive syntax described below. The values used for the script name and its arguments are subject to placeholder replacement. In addition to the standard Caddy placeholders such as {method} and {host}, the following placeholder substitutions are made: - {.} is replaced with Caddy’s current working directory - {match} is replaced with the portion of the request that satisfies the match directive - {root} is replaced with Caddy’s specified root directory You can include glob wildcards in your matches. Basically, an asterisk represents a sequence of zero or more non-slash characters and a question mark represents a single non-slash character. These wildcards can be used multiple times in a match expression. See the documentation for path/Match in the Go standard library for more details about glob matching. Here is an example directive: In this case, the cgi middleware will match requests such as https://example.com/report/weekly.lua and https://example.com/report/report.lua/weekly but not https://example.com/report.lua. The use of the asterisk expands to any character sequence within a directory. For example, if the request is made, the following command is executed: Note that the portion of the request that follows the match is not included. That information is conveyed to the script by means of environment variables. In this example, the Lua interpreter is invoked directly from Caddy, so the Lua script does not need the shebang that would be needed in a standalone script. This method facilitates the use of CGI on the Windows platform. In order to specify custom environment variables, pass along one or more environment variables known to Caddy, or specify more than one match pattern for a given rule, you will need to use the advanced directive syntax. That looks like this: For example, With the advanced syntax, the exec subdirective must appear exactly once. The match subdirective must appear at least once. The env, pass_env, empty_env, and except subdirectives can appear any reasonable number of times. pass_all_env, dir may appear once. The dir subdirective specifies the CGI executable’s working directory. If it is not specified, Caddy’s current working directory is used. The except subdirective uses the same pattern matching logic that is used with the match subdirective except that the request must match a rule fully; no request path prefix matching is performed. Any request that matches a match pattern is then checked with the patterns in except, if any. If any matches are made with the except pattern, the request is rejected and passed along to subsequent handlers. This is a convenient way to have static file resources served properly rather than being confused as CGI applications. The empty_env subdirective is used to pass one or more empty environment variables. Some CGI scripts may expect the server to pass certain empty variables rather than leaving them unset. This subdirective allows you to deal with those situations. The values associated with environment variable keys are all subject to placeholder substitution, just as with the script name and arguments. If your CGI application runs properly at the command line but fails to run from Caddy it is possible that certain environment variables may be missing. For example, the ruby gem loader evidently requires the HOME environment variable to be set; you can do this with the subdirective pass_env HOME. Another class of problematic applications require the COMPUTERNAME variable. The pass_all_env subdirective instructs Caddy to pass each environment variable it knows about to the CGI excutable. This addresses a common frustration that is caused when an executable requires an environment variable and fails without a descriptive error message when the variable cannot be found. These applications often run fine from the command prompt but fail when invoked with CGI. The risk with this subdirective is that a lot of server information is shared with the CGI executable. Use this subdirective only with CGI applications that you trust not to leak this information. If you protect your CGI application with the Caddy JWT middleware, your program will have access to the token’s payload claims by means of environment variables. For example, the following token claims will be available with the following environment variables All values are conveyed as strings, so some conversion may be necessary in your program. No placeholder substitutions are made on these values. If you run into unexpected results with the CGI plugin, you are able to examine the environment in which your CGI application runs. To enter inspection mode, add the subdirective inspect to your CGI configuration block. This is a development option that should not be used in production. When in inspection mode, the plugin will respond to matching requests with a page that displays variables of interest. In particular, it will show the replacement value of {match} and the environment variables to which your CGI application has access. For example, consider this example CGI block: When you request a matching URL, for example, the Caddy server will deliver a text page similar to the following. The CGI application (in this case, wapptclsh) will not be called. This information can be used to diagnose problems with how a CGI application is called. To return to operation mode, remove or comment out the inspect subdirective. In this example, the Caddyfile looks like this: Note that a request for /show gets mapped to a script named /usr/local/cgi-bin/report/gen. There is no need for any element of the script name to match any element of the match pattern. The contents of /usr/local/cgi-bin/report/gen are: The purpose of this script is to show how request information gets communicated to a CGI script. Note that POST data must be read from standard input. In this particular case, posted data gets stored in the variable POST_DATA. Your script may use a different method to read POST content. Secondly, the SCRIPT_EXEC variable is not a CGI standard. It is provided by this middleware and contains the entire command line, including all arguments, with which the CGI script was executed. When a browser requests the response looks like When a client makes a POST request, such as with the following command the response looks the same except for the following lines: The fossil distributed software management tool is a native executable that supports interaction as a CGI application. In this example, /usr/bin/fossil is the executable and /home/quixote/projects.fossil is the fossil repository. To configure Caddy to serve it, use a cgi directive something like this in your Caddyfile: In your /usr/local/cgi-bin directory, make a file named projects with the following single line: The fossil documentation calls this a command file. When fossil is invoked after a request to /projects, it examines the relevant environment variables and responds as a CGI application. If you protect /projects with basic HTTP authentication, you may wish to enable the ALLOW REMOTE_USER AUTHENTICATION option when setting up fossil. This lets fossil dispense with its own authentication, assuming it has an account for the user. The agedu utility can be used to identify unused files that are taking up space on your storage media. Like fossil, it can be used in different modes including CGI. First, use it from the command line to generate an index of a directory, for example In your Caddyfile, include a directive that references the generated index: You will want to protect the /agedu resource with some sort of access control, for example HTTP Basic Authentication. This small example demonstrates how to write a CGI program in Go. The use of a bytes.Buffer makes it easy to report the content length in the CGI header. When this program is compiled and installed as /usr/local/bin/servertime, the following directive in your Caddy file will make it available: The cgit application provides an attractive and useful web interface to git repositories. Here is how to run it with Caddy. After compiling cgit, you can place the executable somewhere out of Caddy’s document root. In this example, it is located in /usr/local/cgi-bin. A sample configuration file is included in the project’s cgitrc.5.txt file. You can use it as a starting point for your configuration. The default location for this file is /etc/cgitrc but in this example the location /home/quixote/caddy/cgitrc. Note that changing the location of this file from its default will necessitate the inclusion of the environment variable CGIT_CONFIG in the Caddyfile cgi directive. When you edit the repository stanzas in this file, be sure each repo.path item refers to the .git directory within a working checkout. Here is an example stanza: Also, you will likely want to change cgit’s cache directory from its default in /var/cache (generally accessible only to root) to a location writeable by Caddy. In this example, cgitrc contains the line You may need to create the cgit subdirectory. There are some static cgit resources (namely, cgit.css, favicon.ico, and cgit.png) that will be accessed from Caddy’s document tree. For this example, these files are placed in a directory named cgit-resource. The following lines are part of the cgitrc file: Additionally, you will likely need to tweak the various file viewer filters such source-filter and about-filter based on your system. The following Caddyfile directive will allow you to access the cgit application at /cgit: Feeling reckless? You can run PHP in CGI mode. In general, FastCGI is the preferred method to run PHP if your application has many pages or a fair amount of database activity. But for small PHP programs that are seldom used, CGI can work fine. You’ll need the php-cgi interpreter for your platform. This may involve downloading the executable or downloading and then compiling the source code. For this example, assume the interpreter is installed as /usr/local/bin/php-cgi. Additionally, because of the way PHP operates in CGI mode, you will need an intermediate script. This one works in Posix environments: This script can be reused for multiple cgi directives. In this example, it is installed as /usr/local/cgi-bin/phpwrap. The argument following -c is your initialization file for PHP. In this example, it is named /home/quixote/.config/php/php-cgi.ini. Two PHP files will be used for this example. The first, /usr/local/cgi-bin/sample/min.php, looks like this: The second, /usr/local/cgi-bin/sample/action.php, follows: The following directive in your Caddyfile will make the application available at sample/min.php: This examples demonstrates printing a CGI rule

This is the official Go SDK for Oracle Cloud Infrastructure Refer to https://github.com/oracle/oci-go-sdk/blob/master/README.md#installing for installation instructions. Refer to https://github.com/oracle/oci-go-sdk/blob/master/README.md#configuring for configuration instructions. The following example shows how to get started with the SDK. The example belows creates an identityClient struct with the default configuration. It then utilizes the identityClient to list availability domains and prints them out to stdout More examples can be found in the SDK Github repo: https://github.com/oracle/oci-go-sdk/tree/master/example Optional fields are represented with the `mandatory:"false"` tag on input structs. The SDK will omit all optional fields that are nil when making requests. In the case of enum-type fields, the SDK will omit fields whose value is an empty string. The SDK uses pointers for primitive types in many input structs. To aid in the construction of such structs, the SDK provides functions that return a pointer for a given value. For example: The SDK exposes functionality that allows the user to customize any http request before is sent to the service. You can do so by setting the `Interceptor` field in any of the `Client` structs. For example: The Interceptor closure gets called before the signing process, thus any changes done to the request will be properly signed and submitted to the service. The SDK exposes a stand-alone signer that can be used to signing custom requests. Related code can be found here: https://github.com/oracle/oci-go-sdk/blob/master/common/http_signer.go. The example below shows how to create a default signer. The signer also allows more granular control on the headers used for signing. For example: You can combine a custom signer with the exposed clients in the SDK. This allows you to add custom signed headers to the request. Following is an example: Bear in mind that some services have a white list of headers that it expects to be signed. Therefore, adding an arbitrary header can result in authentications errors. To see a runnable example, see https://github.com/oracle/oci-go-sdk/blob/master/example/example_identity_test.go For more information on the signing algorithm refer to: https://docs.cloud.oracle.com/Content/API/Concepts/signingrequests.htm Some operations accept or return polymorphic JSON objects. The SDK models such objects as interfaces. Further the SDK provides structs that implement such interfaces. Thus, for all operations that expect interfaces as input, pass the struct in the SDK that satisfies such interface. For example: In the case of a polymorphic response you can type assert the interface to the expected type. For example: An example of polymorphic JSON request handling can be found here: https://github.com/oracle/oci-go-sdk/blob/master/example/example_core_test.go#L63 When calling a list operation, the operation will retrieve a page of results. To retrieve more data, call the list operation again, passing in the value of the most recent response's OpcNextPage as the value of Page in the next list operation call. When there is no more data the OpcNextPage field will be nil. An example of pagination using this logic can be found here: https://github.com/oracle/oci-go-sdk/blob/master/example/example_core_pagination_test.go The SDK has a built-in logging mechanism used internally. The internal logging logic is used to record the raw http requests, responses and potential errors when (un)marshalling request and responses. Built-in logging in the SDK is controlled via the environment variable "OCI_GO_SDK_DEBUG" and its contents. The below are possible values for the "OCI_GO_SDK_DEBUG" variable 1. "info" or "i" enables all info logging messages 2. "debug" or "d" enables all debug and info logging messages 3. "verbose" or "v" or "1" enables all verbose, debug and info logging messages 4. "null" turns all logging messages off. If the value of the environment variable does not match any of the above then default logging level is "info". If the environment variable is not present then no logging messages are emitted. The default destination for logging is Stderr and if you want to output log to a file you can set via environment variable "OCI_GO_SDK_LOG_OUTPUT_MODE". The below are possible values 1. "file" or "f" enables all logging output saved to file 2. "combine" or "c" enables all logging output to both stderr and file You can also customize the log file location and name via "OCI_GO_SDK_LOG_FILE" environment variable, the value should be the path to a specific file If this environment variable is not present, the default location will be the project root path Sometimes you may need to wait until an attribute of a resource, such as an instance or a VCN, reaches a certain state. An example of this would be launching an instance and then waiting for the instance to become available, or waiting until a subnet in a VCN has been terminated. You might also want to retry the same operation again if there's network issue etc... This can be accomplished by using the RequestMetadata.RetryPolicy. You can find the examples here: https://github.com/oracle/oci-go-sdk/blob/master/example/example_retry_test.go The GO SDK uses the net/http package to make calls to OCI services. If your environment requires you to use a proxy server for outgoing HTTP requests then you can set this up in the following ways: 1. Configuring environment variable as described here https://golang.org/pkg/net/http/#ProxyFromEnvironment 2. Modifying the underlying Transport struct for a service client In order to modify the underlying Transport struct in HttpClient, you can do something similar to (sample code for audit service client): The Object Storage service supports multipart uploads to make large object uploads easier by splitting the large object into parts. The Go SDK supports raw multipart upload operations for advanced use cases, as well as a higher level upload class that uses the multipart upload APIs. For links to the APIs used for multipart upload operations, see Managing Multipart Uploads (https://docs.cloud.oracle.com/iaas/Content/Object/Tasks/usingmultipartuploads.htm). Higher level multipart uploads are implemented using the UploadManager, which will: split a large object into parts for you, upload the parts in parallel, and then recombine and commit the parts as a single object in storage. This code sample shows how to use the UploadManager to automatically split an object into parts for upload to simplify interaction with the Object Storage service: https://github.com/oracle/oci-go-sdk/blob/master/example/example_objectstorage_test.go Some response fields are enum-typed. In the future, individual services may return values not covered by existing enums for that field. To address this possibility, every enum-type response field is a modeled as a type that supports any string. Thus if a service returns a value that is not recognized by your version of the SDK, then the response field will be set to this value. When individual services return a polymorphic JSON response not available as a concrete struct, the SDK will return an implementation that only satisfies the interface modeling the polymorphic JSON response. If you are using a version of the SDK released prior to the announcement of a new region, you may need to use a workaround to reach it, depending on whether the region is in the oraclecloud.com realm. A region is a localized geographic area. For more information on regions and how to identify them, see Regions and Availability Domains(https://docs.cloud.oracle.com/iaas/Content/General/Concepts/regions.htm). A realm is a set of regions that share entities. You can identify your realm by looking at the domain name at the end of the network address. For example, the realm for xyz.abc.123.oraclecloud.com is oraclecloud.com. oraclecloud.com Realm: For regions in the oraclecloud.com realm, even if common.Region does not contain the new region, the forward compatibility of the SDK can automatically handle it. You can pass new region names just as you would pass ones that are already defined. For more information on passing region names in the configuration, see Configuring (https://github.com/oracle/oci-go-sdk/blob/master/README.md#configuring). For details on common.Region, see (https://github.com/oracle/oci-go-sdk/blob/master/common/common.go). Other Realms: For regions in realms other than oraclecloud.com, you can use the following workarounds to reach new regions with earlier versions of the SDK. NOTE: Be sure to supply the appropriate endpoints for your region. You can overwrite the target host with client.Host: If you are authenticating via instance principals, you can set the authentication endpoint in an environment variable: Got a fix for a bug, or a new feature you'd like to contribute? The SDK is open source and accepting pull requests on GitHub https://github.com/oracle/oci-go-sdk Licensing information available at: https://github.com/oracle/oci-go-sdk/blob/master/LICENSE.txt To be notified when a new version of the Go SDK is released, subscribe to the following feed: https://github.com/oracle/oci-go-sdk/releases.atom Please refer to this link: https://github.com/oracle/oci-go-sdk#help

Package flume is a logging package, build on top of zap. It's structured and leveled logs, like zap/logrus/etc. It adds global, runtime re-configuration of all loggers, via an internal logger registry. There are two interaction points with flume: code that generates logs, and code that configures logging output. Code which generates logs needs to create named logger instances, and call log functions on it, like Info() and Debug(). But by default, all these logs will be silently discarded. Flume does not output log entries unless explicitly told to do so. This ensures libraries can freely use flume internally, without polluting the stdout of the programs importing the library. The Logger type is a small interface. Libraries should allow replacement of their Logger instances so importers can entirely replace flume if they wish. Alternately, importers can use flume to configure the library's log output, and/or redirect it into the overall program's log stream. This package does not offer package level log functions, so you need to create a logger instance first: A common pattern is to create a single, package-wide logger, named after the package: Then, write some logs: Logs have a message, then matched pairs of key/value properties. Child loggers can be created and pre-seeded with a set of properties: Expensive log events can be avoid by explicitly checking level: Loggers can be bound to context.Context, which is convenient for carrying per-transaction loggers (pre-seeded with transaction specific context) through layers of request processing code: The standard Logger interface only supports 3 levels of log, DBG, INF, and ERR. This is inspired by this article: https://dave.cheney.net/2015/11/05/lets-talk-about-logging. However, you can create instances of DeprecatedLogger instead, which support more levels. There are several package level functions which reconfigure logging output. They control which levels are discarded, which fields are included in each log entry, and how those fields are rendered, and how the overall log entry is rendered (JSON, LTSV, colorized, etc). To configure logging settings from environment variables, call the configuration function from main(): This reads the log configuration from the environment variable "FLUME" (the default, which can be overridden). The value is JSON, e.g.: The properties of the config string: "level": ERR, INF, or DBG. The default level for all loggers. "levels": A string configuring log levels for specific loggers, overriding the default level. See note below for syntax. "development": true or false. In development mode, the defaults for the other settings change to be more suitable for developers at a terminal (colorized, multiline, human readable, etc). See note below for exact defaults. "addCaller": true or false. Adds call site information to log entries (file and line). "encoding": json, ltsv, term, or term-color. Configures how log entries are encoded in the output. "term" and "term-color" are multi-line, human-friendly formats, intended for terminal output. "encoderConfig": a JSON object which configures advanced encoding settings, like how timestamps are formatted. See docs for go.uber.org/zap/zapcore/EncoderConfig "messageKey": the label of the message property of the log entry. If empty, message is omitted. "levelKey": the label of the level property of the log entry. If empty, level is omitted. "timeKey": the label of the timestamp of the log entry. If empty, timestamp is omitted. "nameKey": the label of the logger name in the log entry. If empty, logger name is omitted. "callerKey": the label of the logger name in the log entry. If empty, logger name is omitted. "lineEnding": the end of each log output line. "levelEncoder": capital, capitalColor, color, lower, or abbr. Controls how the log entry level is rendered. "abbr" renders 3-letter abbreviations, like ERR and INF. "timeEncoder": iso8601, millis, nanos, unix, or justtime. Controls how timestamps are rendered. "millis", "nanos", and "unix" are since UNIX epoch. "unix" is in floating point seconds. "justtime" omits the date, and just prints the time in the format "15:04:05.000". "durationEncoder": string, nanos, or seconds. Controls how time.Duration values are rendered. "callerEncoder": full or short. Controls how the call site is rendered. "full" includes the entire package path, "short" only includes the last folder of the package. Defaults: These defaults are only applied if one of the configuration functions is called, like ConfigFromEnv(), ConfigString(), Configure(), or LevelsString(). Initially, all loggers are configured to discard everything, following flume's opinion that log packages should be silent unless spoken too. Ancillary to this: library packages should *not* call these functions, or configure logging levels or output in anyway. Only program entry points, like main() or test code, should configure logging. Libraries should just create loggers and log to them. Development mode: if "development"=true, the defaults for the rest of the settings change, equivalent to: The "levels" value is a list of key=value pairs, configuring the level of individual named loggers. If the key is "*", it sets the default level. If "level" and "levels" both configure the default level, "levels" wins. Examples: Most usages of flume will use its package functions. The package functions delegate to an internal instance of Factory, which a the logger registry. You can create and manage your own instance of Factory, which will be an isolated set of Loggers. tl;dr The implementation is a wrapper around zap. zap does levels, structured logs, and is very fast. zap doesn't do centralized, global configuration, so this package adds that by maintaining an internal registry of all loggers, and using the sync.atomic stuff to swap out levels and writers in a thread safe way.

Package wlog creates simple to use UI structure. The UI is used to simply print to the screen. There a wrappers that will wrap each other to create a good looking UI. You can add color and prefixes as well as make it thread safe.

Package pretty provides pretty-printing for Go values. This is useful during debugging, to avoid wrapping long output lines in the terminal. It provides a function, Formatter, that can be used with any function that accepts a format string. It also provides convenience wrappers for functions in packages fmt and log.

Taken from $GOROOT/src/pkg/net/http/chunked needed to write https responses to client. Package goproxy provides a customizable HTTP proxy, supporting hijacking HTTPS connection. The intent of the proxy, is to be usable with reasonable amount of traffic yet, customizable and programable. The proxy itself is simply an `net/http` handler. Typical usage is Adding a header to each request For printing the content type of all incoming responses note that we used the ProxyCtx context variable here. It contains the request and the response (Req and Resp, Resp is nil if unavailable) of this specific client interaction with the proxy. To print the content type of all responses from a certain url, we'll add a ReqCondition to the OnResponse function: We can write the condition ourselves, conditions can be set on request and on response Caution! If you give a RespCondition to the OnRequest function, you'll get a run time panic! It doesn't make sense to read the response, if you still haven't got it! Finally, we have convenience function to throw a quick response we close the body of the original repsonse, and return a new 403 response with a short message.

The sampletests command adds the region tags tested by each test to the XML properties of that test case. It reads JUnit XML from stdin and writes JUnit XML to stdout. For example, if TestFoo tests the regions foo_hello_world and foo_hello_gopher, the TestFoo element will have the following property: sampletests only looks at direct function calls or references by tests. So, if you have a map from string -> function reference in the global scope and test functions only reference the string, sampletests will not work. There are some duplicate region tags, but they aren't tracked anywhere else, so it's OK if they are "applied" to more than one test. sampletests only looks in the current module, which matches the behavior of `go test`. So, if you run `go test ./...` and sampletests in the same directory they should both find the same set of packages. The test coverage over all regions is printed to stderr at the end. The coverage is based on the entire module, not just the tests that happen to be in the given XML input. The XML may not be for for all tests in the module. Warnings are printed to stderr for invalid region tags (e.g. mis-matched START and END tags). The -enable_xml flag can be used to disable XML processing and only print warnings and coverage. To get the number of unique region tags in the repo manually, run:

Pretty(ish) print configuration output on application startup! Make it easy to see what those env vars actually told your app to do! The most basic usage is: Which will print out an output something like: You may configure a Printer for your specific needs if the default usage is not suited to your purposes.

Package collection seeks to provide an expressive and readable way of working with basic data structures in Go. As a former .NET developer, I deeply missed writing programs in the style of Linq. Doing so enables concurrent/ parallel reactive programs to be written in a snap. Go's functional nature enables us to have a very similar, if more verbose, experience. Take for example the scenario of printing the number of Go source files in a directory. Using this package, this takes only a few lines: A directory is a collection of filesystem entries, so we're able to iterate through them using the "Enumerate" function. From there, we filter on only file names that end with ".go". Finally, we print the number of entries that were encountered. This is a trivial example, but imagine building more elaborate pipelines. Maybe take advantage of the `SelectParallel` function which allows multiple goroutines to process a single transform at once, with their results being funnelled into the next phase of the pipeline. Suddenly, injecting new steps can be transparent.

Taken from $GOROOT/src/pkg/net/http/chunked needed to write https responses to client. Package goproxy provides a customizable HTTP proxy, supporting hijacking HTTPS connection. The intent of the proxy, is to be usable with reasonable amount of traffic yet, customizable and programable. The proxy itself is simply an `net/http` handler. Typical usage is Adding a header to each request For printing the content type of all incoming responses note that we used the ProxyCtx context variable here. It contains the request and the response (Req and Resp, Resp is nil if unavailable) of this specific client interaction with the proxy. To print the content type of all responses from a certain url, we'll add a ReqCondition to the OnResponse function: We can write the condition ourselves, conditions can be set on request and on response Caution! If you give a RespCondition to the OnRequest function, you'll get a run time panic! It doesn't make sense to read the response, if you still haven't got it! Finally, we have convenience function to throw a quick response we close the body of the original repsonse, and return a new 403 response with a short message. Example use cases: 1. https://github.com/elazarl/goproxy/tree/master/examples/goproxy-avgsize To measure the average size of an Html served in your site. One can ask all the QA team to access the website by a proxy, and the proxy will measure the average size of all text/html responses from your host. 2. [not yet implemented] All requests to your web servers should be directed through the proxy, when the proxy will detect html pieces sent as a response to AJAX request, it'll send a warning email. 3. https://github.com/elazarl/goproxy/blob/master/examples/goproxy-httpdump/ Generate a real traffic to your website by real users using through proxy. Record the traffic, and try it again for more real load testing. 4. https://github.com/elazarl/goproxy/tree/master/examples/goproxy-no-reddit-at-worktime Will allow browsing to reddit.com between 8:00am and 17:00pm 5. https://github.com/elazarl/goproxy/tree/master/examples/goproxy-jquery-version Will warn if multiple versions of jquery are used in the same domain. 6. https://github.com/elazarl/goproxy/blob/master/examples/goproxy-upside-down-ternet/ Modifies image files in an HTTP response via goproxy's image extension found in ext/.

Package errors provides simple error handling primitives. The traditional error handling idiom in Go is roughly akin to which when applied recursively up the call stack results in error reports without context or debugging information. The errors package allows programmers to add context to the failure path in their code in a way that does not destroy the original value of the error. The errors.Wrap function returns a new error that adds context to the original error by recording a stack trace at the point Wrap is called, together with the supplied message. For example If additional control is required, the errors.WithStack and errors.WithMessage functions destructure errors.Wrap into its component operations: annotating an error with a stack trace and with a message, respectively. Using errors.Wrap constructs a stack of errors, adding context to the preceding error. Depending on the nature of the error it may be necessary to reverse the operation of errors.Wrap to retrieve the original error for inspection. Any error value which implements this interface can be inspected by errors.Cause. errors.Cause will recursively retrieve the topmost error that does not implement causer, which is assumed to be the original cause. For example: Although the causer interface is not exported by this package, it is considered a part of its stable public interface. All error values returned from this package implement fmt.Formatter and can be formatted by the fmt package. The following verbs are supported: New, Errorf, Wrap, and Wrapf record a stack trace at the point they are invoked. This information can be retrieved with the following interface: The returned errors.StackTrace type is defined as The Frame type represents a call site in the stack trace. Frame supports the fmt.Formatter interface that can be used for printing information about the stack trace of this error. For example: Although the stackTracer interface is not exported by this package, it is considered a part of its stable public interface. See the documentation for Frame.Format for more details.

Package errors provides simple error handling primitives. The traditional error handling idiom in Go is roughly akin to which when applied recursively up the call stack results in error reports without context or debugging information. The errors package allows programmers to add context to the failure path in their code in a way that does not destroy the original value of the error. The errors.Wrap function returns a new error that adds context to the original error by recording a stack trace at the point Wrap is called, together with the supplied message. For example If additional control is required, the errors.WithStack and errors.WithMessage functions destructure errors.Wrap into its component operations: annotating an error with a stack trace and with a message, respectively. Using errors.Wrap constructs a stack of errors, adding context to the preceding error. Depending on the nature of the error it may be necessary to reverse the operation of errors.Wrap to retrieve the original error for inspection. Any error value which implements this interface can be inspected by errors.Cause. errors.Cause will recursively retrieve the topmost error that does not implement causer, which is assumed to be the original cause. For example: Although the causer interface is not exported by this package, it is considered a part of its stable public interface. All error values returned from this package implement fmt.Formatter and can be formatted by the fmt package. The following verbs are supported: New, Errorf, Wrap, and Wrapf record a stack trace at the point they are invoked. This information can be retrieved with the following interface: The returned errors.StackTrace type is defined as The Frame type represents a call site in the stack trace. Frame supports the fmt.Formatter interface that can be used for printing information about the stack trace of this error. For example: Although the stackTracer interface is not exported by this package, it is considered a part of its stable public interface. See the documentation for Frame.Format for more details.

Package errors provides simple error handling primitives. The traditional error handling idiom in Go is roughly akin to which when applied recursively up the call stack results in error reports without context or debugging information. The errors package allows programmers to add context to the failure path in their code in a way that does not destroy the original value of the error. The errors.Wrap function returns a new error that adds context to the original error by recording a stack trace at the point Wrap is called, together with the supplied message. For example If additional control is required, the errors.WithStack and errors.WithMessage functions destructure errors.Wrap into its component operations: annotating an error with a stack trace and with a message, respectively. Using errors.Wrap constructs a stack of errors, adding context to the preceding error. Depending on the nature of the error it may be necessary to reverse the operation of errors.Wrap to retrieve the original error for inspection. Any error value which implements this interface can be inspected by errors.Cause. errors.Cause will recursively retrieve the topmost error that does not implement causer, which is assumed to be the original cause. For example: Although the causer interface is not exported by this package, it is considered a part of its stable public interface. All error values returned from this package implement fmt.Formatter and can be formatted by the fmt package. The following verbs are supported: New, Errorf, Wrap, and Wrapf record a stack trace at the point they are invoked. This information can be retrieved with the following interface: The returned errors.StackTrace type is defined as The Frame type represents a call site in the stack trace. Frame supports the fmt.Formatter interface that can be used for printing information about the stack trace of this error. For example: Although the stackTracer interface is not exported by this package, it is considered a part of its stable public interface. See the documentation for Frame.Format for more details.

Package zalgo implements a zalgo text io.Writer. In addition to providing the basic Zalgo text transformation, two default transformers are provided: These defaults are set with what are reasonable defaults (whatever that might mean in this context). So for example: will print something like the following to stdout:

Package gofpdf implements a PDF document generator with high level support for text, drawing and images. - UTF-8 support - Choice of measurement unit, page format and margins - Page header and footer management - Automatic page breaks, line breaks, and text justification - Inclusion of JPEG, PNG, GIF, TIFF and basic path-only SVG images - Colors, gradients and alpha channel transparency - Outline bookmarks - Internal and external links - TrueType, Type1 and encoding support - Page compression - Lines, Bézier curves, arcs, and ellipses - Rotation, scaling, skewing, translation, and mirroring - Clipping - Document protection - Layers - Templates - Barcodes - Charting facility - Import PDFs as templates gofpdf has no dependencies other than the Go standard library. All tests pass on Linux, Mac and Windows platforms. gofpdf supports UTF-8 TrueType fonts and “right-to-left” languages. Note that Chinese, Japanese, and Korean characters may not be included in many general purpose fonts. For these languages, a specialized font (for example, NotoSansSC for simplified Chinese) can be used. Also, support is provided to automatically translate UTF-8 runes to code page encodings for languages that have fewer than 256 glyphs. This repository will not be maintained, at least for some unknown duration. But it is hoped that gofpdf has a bright future in the open source world. Due to Go’s promise of compatibility, gofpdf should continue to function without modification for a longer time than would be the case with many other languages. Forks should be based on the last viable commit. Tools such as active-forks can be used to select a fork that looks promising for your needs. If a particular fork looks like it has taken the lead in attracting followers, this README will be updated to point people in that direction. The efforts of all contributors to this project have been deeply appreciated. Best wishes to all of you. If you currently use the $GOPATH scheme, install the package with the following command. To test the installation, run The following Go code generates a simple PDF file. See the functions in the fpdf_test.go file (shown as examples in this documentation) for more advanced PDF examples. If an error occurs in an Fpdf method, an internal error field is set. After this occurs, Fpdf method calls typically return without performing any operations and the error state is retained. This error management scheme facilitates PDF generation since individual method calls do not need to be examined for failure; it is generally sufficient to wait until after Output() is called. For the same reason, if an error occurs in the calling application during PDF generation, it may be desirable for the application to transfer the error to the Fpdf instance by calling the SetError() method or the SetErrorf() method. At any time during the life cycle of the Fpdf instance, the error state can be determined with a call to Ok() or Err(). The error itself can be retrieved with a call to Error(). This package is a relatively straightforward translation from the original FPDF library written in PHP (despite the caveat in the introduction to Effective Go). The API names have been retained even though the Go idiom would suggest otherwise (for example, pdf.GetX() is used rather than simply pdf.X()). The similarity of the two libraries makes the original FPDF website a good source of information. It includes a forum and FAQ. However, some internal changes have been made. Page content is built up using buffers (of type bytes.Buffer) rather than repeated string concatenation. Errors are handled as explained above rather than panicking. Output is generated through an interface of type io.Writer or io.WriteCloser. A number of the original PHP methods behave differently based on the type of the arguments that are passed to them; in these cases additional methods have been exported to provide similar functionality. Font definition files are produced in JSON rather than PHP. A side effect of running go test ./... is the production of a number of example PDFs. These can be found in the gofpdf/pdf directory after the tests complete. Please note that these examples run in the context of a test. In order run an example as a standalone application, you’ll need to examine fpdf_test.go for some helper routines, for example exampleFilename() and summary(). Example PDFs can be compared with reference copies in order to verify that they have been generated as expected. This comparison will be performed if a PDF with the same name as the example PDF is placed in the gofpdf/pdf/reference directory and if the third argument to ComparePDFFiles() in internal/example/example.go is true. (By default it is false.) The routine that summarizes an example will look for this file and, if found, will call ComparePDFFiles() to check the example PDF for equality with its reference PDF. If differences exist between the two files they will be printed to standard output and the test will fail. If the reference file is missing, the comparison is considered to succeed. In order to successfully compare two PDFs, the placement of internal resources must be consistent and the internal creation timestamps must be the same. To do this, the methods SetCatalogSort() and SetCreationDate() need to be called for both files. This is done automatically for all examples. Nothing special is required to use the standard PDF fonts (courier, helvetica, times, zapfdingbats) in your documents other than calling SetFont(). You should use AddUTF8Font() or AddUTF8FontFromBytes() to add a TrueType UTF-8 encoded font. Use RTL() and LTR() methods switch between “right-to-left” and “left-to-right” mode. In order to use a different non-UTF-8 TrueType or Type1 font, you will need to generate a font definition file and, if the font will be embedded into PDFs, a compressed version of the font file. This is done by calling the MakeFont function or using the included makefont command line utility. To create the utility, cd into the makefont subdirectory and run “go build”. This will produce a standalone executable named makefont. Select the appropriate encoding file from the font subdirectory and run the command as in the following example. In your PDF generation code, call AddFont() to load the font and, as with the standard fonts, SetFont() to begin using it. Most examples, including the package example, demonstrate this method. Good sources of free, open-source fonts include Google Fonts and DejaVu Fonts. The draw2d package is a two dimensional vector graphics library that can generate output in different forms. It uses gofpdf for its document production mode. gofpdf is a global community effort and you are invited to make it even better. If you have implemented a new feature or corrected a problem, please consider contributing your change to the project. A contribution that does not directly pertain to the core functionality of gofpdf should be placed in its own directory directly beneath the contrib directory. Here are guidelines for making submissions. Your change should - be compatible with the MIT License - be properly documented - be formatted with go fmt - include an example in fpdf_test.go if appropriate - conform to the standards of golint and go vet, that is, golint . and go vet . should not generate any warnings - not diminish test coverage Pull requests are the preferred means of accepting your changes. gofpdf is released under the MIT License. It is copyrighted by Kurt Jung and the contributors acknowledged below. This package’s code and documentation are closely derived from the FPDF library created by Olivier Plathey, and a number of font and image resources are copied directly from it. Bruno Michel has provided valuable assistance with the code. Drawing support is adapted from the FPDF geometric figures script by David Hernández Sanz. Transparency support is adapted from the FPDF transparency script by Martin Hall-May. Support for gradients and clipping is adapted from FPDF scripts by Andreas Würmser. Support for outline bookmarks is adapted from Olivier Plathey by Manuel Cornes. Layer support is adapted from Olivier Plathey. Support for transformations is adapted from the FPDF transformation script by Moritz Wagner and Andreas Würmser. PDF protection is adapted from the work of Klemen Vodopivec for the FPDF product. Lawrence Kesteloot provided code to allow an image’s extent to be determined prior to placement. Support for vertical alignment within a cell was provided by Stefan Schroeder. Ivan Daniluk generalized the font and image loading code to use the Reader interface while maintaining backward compatibility. Anthony Starks provided code for the Polygon function. Robert Lillack provided the Beziergon function and corrected some naming issues with the internal curve function. Claudio Felber provided implementations for dashed line drawing and generalized font loading. Stani Michiels provided support for multi-segment path drawing with smooth line joins, line join styles, enhanced fill modes, and has helped greatly with package presentation and tests. Templating is adapted by Marcus Downing from the FPDF_Tpl library created by Jan Slabon and Setasign. Jelmer Snoeck contributed packages that generate a variety of barcodes and help with registering images on the web. Jelmer Snoek and Guillermo Pascual augmented the basic HTML functionality with aligned text. Kent Quirk implemented backwards-compatible support for reading DPI from images that support it, and for setting DPI manually and then having it properly taken into account when calculating image size. Paulo Coutinho provided support for static embedded fonts. Dan Meyers added support for embedded JavaScript. David Fish added a generic alias-replacement function to enable, among other things, table of contents functionality. Andy Bakun identified and corrected a problem in which the internal catalogs were not sorted stably. Paul Montag added encoding and decoding functionality for templates, including images that are embedded in templates; this allows templates to be stored independently of gofpdf. Paul also added support for page boxes used in printing PDF documents. Wojciech Matusiak added supported for word spacing. Artem Korotkiy added support of UTF-8 fonts. Dave Barnes added support for imported objects and templates. Brigham Thompson added support for rounded rectangles. Joe Westcott added underline functionality and optimized image storage. Benoit KUGLER contributed support for rectangles with corners of unequal radius, modification times, and for file attachments and annotations. - Remove all legacy code page font support; use UTF-8 exclusively - Improve test coverage as reported by the coverage tool. Example demonstrates the generation of a simple PDF document. Note that since only core fonts are used (in this case Arial, a synonym for Helvetica), an empty string can be specified for the font directory in the call to New(). Note also that the example.Filename() and example.Summary() functions belong to a separate, internal package and are not part of the gofpdf library. If an error occurs at some point during the construction of the document, subsequent method calls exit immediately and the error is finally retrieved with the output call where it can be handled by the application.

Package color is an ANSI color package to output colorized or SGR defined output to the standard output. The API can be used in several way, pick one that suits you. Use simple and default helper functions with predefined foreground colors: However there are times where custom color mixes are required. Below are some examples to create custom color objects and use the print functions of each separate color object. You can create PrintXxx functions to simplify even more: Or create SprintXxx functions to mix strings with other non-colorized strings: Windows support is enabled by default. All Print functions works as intended. However only for color.SprintXXX functions, user should use fmt.FprintXXX and set the output to color.Output: Using with existing code is possible. Just use the Set() method to set the standard output to the given parameters. That way a rewrite of an existing code is not required. There might be a case where you want to disable color output (for example to pipe the standard output of your app to somewhere else). `Color` has support to disable colors both globally and for single color definition. For example suppose you have a CLI app and a `--no-color` bool flag. You can easily disable the color output with: It also has support for single color definitions (local). You can disable/enable color output on the fly: