mirror of
https://github.com/ceph/ceph-csi.git
synced 2024-11-14 10:20:20 +00:00
91 lines
3.4 KiB
Go
91 lines
3.4 KiB
Go
// Package merry provides enriched golang errors, with stacktraces
|
|
//
|
|
// merry creates errors with stacktraces, and can augment those errors with additional
|
|
// information.
|
|
//
|
|
// When you create a new merry error, or wrap an existing error in a merry error, merry attaches
|
|
// a stacktrace to the error:
|
|
//
|
|
// err := merry.New("an error occurred")
|
|
//
|
|
// err has a stacktrace attached. Alternately, you can wrap existing errors. merry will
|
|
// attach a stacktrace at the point of wrapping:
|
|
//
|
|
// _, err := ioutil.ReadAll(r)
|
|
// if err != nil {
|
|
// return merry.Wrap(err)
|
|
// }
|
|
//
|
|
// Capturing the stack can be globally disabled with `SetStackCaptureEnabled(false)`. Wrapping
|
|
// is idempotent: Wrap will only attach a stacktrace if the error doesn't already have one.
|
|
//
|
|
// Wrap() is the simplest way to attach a stacktrace to an error, but other functions can be
|
|
// used instead, with both add a stacktrace, and augment or modify the error. For example,
|
|
// Prepend() modifies the error's message (and also attaches a stacktrace):
|
|
//
|
|
// _, err := ioutil.ReadAll(r)
|
|
// if err != nil {
|
|
// return merry.Prepend(err, "reading from conn failed")
|
|
// // err.Error() would read something like "reading from conn failed: timeout"
|
|
// }
|
|
//
|
|
// See the other package functions for other ways to augment or modify errors, such as Append,
|
|
// WithUserMessage, WithHTTPCode, WithValue, etc. These functions all return a merry.Error interface, which
|
|
// has methods which mirror the package level functions, to allow simple chaining:
|
|
//
|
|
// return merry.New("object not found").WithHTTPCode(404)
|
|
//
|
|
// Here
|
|
//
|
|
// Wrap will not take a new stacktrace if an error already has one attached. Here will create
|
|
// a new error which replaces the stacktrace with a new one:
|
|
//
|
|
// var ErrOverflow = merry.New("overflowed")
|
|
//
|
|
// func Read() error {
|
|
// // ...
|
|
// return merry.Here(ErrOverflow)
|
|
// }
|
|
//
|
|
// Is
|
|
//
|
|
// The go idiom of exporting package-level error variables for comparison to errors returned
|
|
// by the package is broken by merry. For example:
|
|
//
|
|
// _, err := io.ReadAll(r)
|
|
// if err == io.EOF {
|
|
// // ...
|
|
// }
|
|
//
|
|
// If the error returned was a merry error, the equality comparison would always fail, because merry
|
|
// augments errors by wrapping them in layers. To compensate for this, merry has the Is() function.
|
|
//
|
|
// if merry.Is(err, io.EOF) {
|
|
//
|
|
// Is() will unwrap the err and compare each layer to the second argument.
|
|
//
|
|
// Cause
|
|
//
|
|
// You can add a cause to an error:
|
|
//
|
|
// if err == io.EOF {
|
|
// err = merry.New("reading failed"), err)
|
|
// fmt.Println(err.Error()) // reading failed: EOF
|
|
// }
|
|
//
|
|
// Cause(error) will return the cause of the argument. RootCause(error) returns the innermost cause.
|
|
// Is(err1, err2) is cause aware, and will return true if err2 is a cause (anywhere in the causal change)
|
|
// of err1.
|
|
//
|
|
// Formatting and printing
|
|
//
|
|
// To obtain an error's stacktrace, call Stack(). To get other information about the site
|
|
// of the error, or print the error's stacktrace, see Location(), SourceLine(), Stacktrace(), and Details().
|
|
//
|
|
// merry errors also implement the fmt.Formatter interface. errors support the following fmt flags:
|
|
//
|
|
// %+v print the equivalent of Details(err), which includes the user message, full stacktrace,
|
|
// and recursively prints the details of the cause chain.
|
|
//
|
|
package merry
|