From 07341f3966675e4875f8cad3c8d86ae502de6d4d Mon Sep 17 00:00:00 2001 From: "Joe Richey joerichey@google.com" Date: Thu, 15 Jun 2017 22:11:50 -0700 Subject: vendor: add in github.com/pkg/errors This commit adds in the github.com/pkg/errors package for handling errors. This allows us to continue to add context to our errors as they move up the call stack, but still be able to switch on their root cause. Change-Id: I6fd55f184318ea1e28c93a84444a2627bff03682 --- vendor/github.com/pkg/errors/README.md | 52 ++++++++++++++++++++++++++++++++++ 1 file changed, 52 insertions(+) create mode 100644 vendor/github.com/pkg/errors/README.md (limited to 'vendor/github.com/pkg/errors/README.md') diff --git a/vendor/github.com/pkg/errors/README.md b/vendor/github.com/pkg/errors/README.md new file mode 100644 index 0000000..273db3c --- /dev/null +++ b/vendor/github.com/pkg/errors/README.md @@ -0,0 +1,52 @@ +# errors [![Travis-CI](https://travis-ci.org/pkg/errors.svg)](https://travis-ci.org/pkg/errors) [![AppVeyor](https://ci.appveyor.com/api/projects/status/b98mptawhudj53ep/branch/master?svg=true)](https://ci.appveyor.com/project/davecheney/errors/branch/master) [![GoDoc](https://godoc.org/github.com/pkg/errors?status.svg)](http://godoc.org/github.com/pkg/errors) [![Report card](https://goreportcard.com/badge/github.com/pkg/errors)](https://goreportcard.com/report/github.com/pkg/errors) + +Package errors provides simple error handling primitives. + +`go get github.com/pkg/errors` + +The traditional error handling idiom in Go is roughly akin to +```go +if err != nil { + return err +} +``` +which 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. + +## Adding context to an error + +The errors.Wrap function returns a new error that adds context to the original error. For example +```go +_, err := ioutil.ReadAll(r) +if err != nil { + return errors.Wrap(err, "read failed") +} +``` +## Retrieving the cause of an error + +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`. +```go +type causer interface { + Cause() error +} +``` +`errors.Cause` will recursively retrieve the topmost error which does not implement `causer`, which is assumed to be the original cause. For example: +```go +switch err := errors.Cause(err).(type) { +case *MyError: + // handle specifically +default: + // unknown error +} +``` + +[Read the package documentation for more information](https://godoc.org/github.com/pkg/errors). + +## Contributing + +We welcome pull requests, bug fixes and issue reports. With that said, the bar for adding new symbols to this package is intentionally set high. + +Before proposing a change, please discuss your change by raising an issue. + +## Licence + +BSD-2-Clause -- cgit v1.3