stack

README


stack

Package stack implements utilities to capture, manipulate, and format call stacks. It provides a simpler API than package runtime.

The implementation takes care of the minutia and special cases of interpreting the program counter (pc) values returned by runtime.Callers.

Versioning

Package stack publishes stable APIs via gopkg.in. The most recent is v0 (the API is still baking, please file an issue if you have any suggestions), which is imported like so:

import "gopkg.in/stack.v0"

Formatting

Package stack's types implement fmt.Formatter, which provides a simple and flexible way to declaratively configure formatting when used with logging or error tracking packages.

func DoTheThing() {
    c := stack.Caller(0)
    log.Print(c)          // might log "source.go:10"
    log.Printf("%+v", c)  // might log "pkg/path/source.go:10"
    log.Printf("%n", c)   // might log "DoTheThing"

    s := stack.Trace().TrimRuntime()
    log.Print(s)          // might log "[source.go:15 caller.go:42 main.go:14]"
}

See the docs for all of the supported formatting options.

Documentation

Overview

Package stack implements utilities to capture, manipulate, and format call stacks. It provides a simpler API than package runtime.

The implementation takes care of the minutia and special cases of interpreting the program counter (pc) values returned by runtime.Callers.

Package stack's types implement fmt.Formatter, which provides a simple and flexible way to declaratively configure formatting when used with logging or error tracking packages.

Example (CallFormat)

//go:build go1.2
// +build go1.2

package main

import (
	"fmt"

	"gopkg.in/stack.v0"
)

func main() {
	logCaller("%+s")
	logCaller("%v   %[1]n()")
}

func logCaller(format string) {
	fmt.Printf(format+"\n", stack.Caller(1))
}

Output:

gopkg.in/stack.v0/format_test.go
format_test.go:13   Example_callFormat()

Index

• type Call
  • func Caller(skip int) Call
  • func (c Call) Format(s fmt.State, verb rune)
• type CallStack
  • func Trace() CallStack
  • func (cs CallStack) Format(s fmt.State, verb rune)
  • func (cs CallStack) TrimAbove(c Call) CallStack
  • func (cs CallStack) TrimBelow(c Call) CallStack
  • func (cs CallStack) TrimRuntime() CallStack

Examples

• Package (CallFormat)

Types

type Call

type Call struct {
	// contains filtered or unexported fields
}

Call records a single function invocation from a goroutine stack.

func Caller

func Caller(skip int) Call

Caller returns a Call from the stack of the current goroutine. The argument skip is the number of stack frames to ascend, with 0 identifying the calling function.

func (Call) Format

func (c Call) Format(s fmt.State, verb rune)

Format implements fmt.Formatter with support for the following verbs.

%s    source file
%d    line number
%n    function name
%v    equivalent to %s:%d

It accepts the '+' and '#' flags for most of the verbs as follows.

%+s   path of source file relative to the compile time GOPATH
%#s   full path of source file
%+n   import path qualified function name
%+v   equivalent to %+s:%d
%#v   equivalent to %#s:%d

type CallStack

type CallStack []Call

CallStack records a sequence of function invocations from a goroutine stack.

func Trace

func Trace() CallStack

Trace returns a CallStack for the current goroutine with element 0 identifying the calling function.

func (CallStack) Format

func (cs CallStack) Format(s fmt.State, verb rune)

Format implements fmt.Formatter by printing the CallStack as square brackes ([, ]) surrounding a space separated list of Calls each formatted with the supplied verb and options.

func (CallStack) TrimAbove

func (cs CallStack) TrimAbove(c Call) CallStack

TrimAbove returns a slice of the CallStack with all entries above c removed.

func (CallStack) TrimBelow

func (cs CallStack) TrimBelow(c Call) CallStack

TrimBelow returns a slice of the CallStack with all entries below c removed.

func (CallStack) TrimRuntime

func (cs CallStack) TrimRuntime() CallStack

TrimRuntime returns a slice of the CallStack with the topmost entries from the go runtime removed. It considers any calls originating from unknown files or files under GOROOT as part of the runtime.