323 lines
8 KiB
Go
323 lines
8 KiB
Go
|
// 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.
|
||
|
|
package stack
|
||
|
|
|
||
|
|
import (
|
||
|
|
"bytes"
|
||
|
|
"errors"
|
||
|
|
"fmt"
|
||
|
|
"io"
|
||
|
|
"runtime"
|
||
|
|
"strconv"
|
||
|
|
"strings"
|
||
|
|
)
|
||
|
|
|
||
|
|
// Call records a single function invocation from a goroutine stack.
|
||
|
|
type Call struct {
|
||
|
|
fn *runtime.Func
|
||
|
|
pc uintptr
|
||
|
|
}
|
||
|
|
|
||
|
|
// 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 Caller(skip int) Call {
|
||
|
|
var pcs [2]uintptr
|
||
|
|
n := runtime.Callers(skip+1, pcs[:])
|
||
|
|
|
||
|
|
var c Call
|
||
|
|
|
||
|
|
if n < 2 {
|
||
|
|
return c
|
||
|
|
}
|
||
|
|
|
||
|
|
c.pc = pcs[1]
|
||
|
|
if runtime.FuncForPC(pcs[0]).Name() != "runtime.sigpanic" {
|
||
|
|
c.pc--
|
||
|
|
}
|
||
|
|
c.fn = runtime.FuncForPC(c.pc)
|
||
|
|
return c
|
||
|
|
}
|
||
|
|
|
||
|
|
// String implements fmt.Stinger. It is equivalent to fmt.Sprintf("%v", c).
|
||
|
|
func (c Call) String() string {
|
||
|
|
return fmt.Sprint(c)
|
||
|
|
}
|
||
|
|
|
||
|
|
// MarshalText implements encoding.TextMarshaler. It formats the Call the same
|
||
|
|
// as fmt.Sprintf("%v", c).
|
||
|
|
func (c Call) MarshalText() ([]byte, error) {
|
||
|
|
if c.fn == nil {
|
||
|
|
return nil, ErrNoFunc
|
||
|
|
}
|
||
|
|
buf := bytes.Buffer{}
|
||
|
|
fmt.Fprint(&buf, c)
|
||
|
|
return buf.Bytes(), nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// ErrNoFunc means that the Call has a nil *runtime.Func. The most likely
|
||
|
|
// cause is a Call with the zero value.
|
||
|
|
var ErrNoFunc = errors.New("no call stack information")
|
||
|
|
|
||
|
|
// 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
|
||
|
|
func (c Call) Format(s fmt.State, verb rune) {
|
||
|
|
if c.fn == nil {
|
||
|
|
fmt.Fprintf(s, "%%!%c(NOFUNC)", verb)
|
||
|
|
return
|
||
|
|
}
|
||
|
|
|
||
|
|
switch verb {
|
||
|
|
case 's', 'v':
|
||
|
|
file, line := c.fn.FileLine(c.pc)
|
||
|
|
switch {
|
||
|
|
case s.Flag('#'):
|
||
|
|
// done
|
||
|
|
case s.Flag('+'):
|
||
|
|
file = file[pkgIndex(file, c.fn.Name()):]
|
||
|
|
default:
|
||
|
|
const sep = "/"
|
||
|
|
if i := strings.LastIndex(file, sep); i != -1 {
|
||
|
|
file = file[i+len(sep):]
|
||
|
|
}
|
||
|
|
}
|
||
|
|
io.WriteString(s, file)
|
||
|
|
if verb == 'v' {
|
||
|
|
buf := [7]byte{':'}
|
||
|
|
s.Write(strconv.AppendInt(buf[:1], int64(line), 10))
|
||
|
|
}
|
||
|
|
|
||
|
|
case 'd':
|
||
|
|
_, line := c.fn.FileLine(c.pc)
|
||
|
|
buf := [6]byte{}
|
||
|
|
s.Write(strconv.AppendInt(buf[:0], int64(line), 10))
|
||
|
|
|
||
|
|
case 'n':
|
||
|
|
name := c.fn.Name()
|
||
|
|
if !s.Flag('+') {
|
||
|
|
const pathSep = "/"
|
||
|
|
if i := strings.LastIndex(name, pathSep); i != -1 {
|
||
|
|
name = name[i+len(pathSep):]
|
||
|
|
}
|
||
|
|
const pkgSep = "."
|
||
|
|
if i := strings.Index(name, pkgSep); i != -1 {
|
||
|
|
name = name[i+len(pkgSep):]
|
||
|
|
}
|
||
|
|
}
|
||
|
|
io.WriteString(s, name)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
// PC returns the program counter for this call frame; multiple frames may
|
||
|
|
// have the same PC value.
|
||
|
|
func (c Call) PC() uintptr {
|
||
|
|
return c.pc
|
||
|
|
}
|
||
|
|
|
||
|
|
// name returns the import path qualified name of the function containing the
|
||
|
|
// call.
|
||
|
|
func (c Call) name() string {
|
||
|
|
if c.fn == nil {
|
||
|
|
return "???"
|
||
|
|
}
|
||
|
|
return c.fn.Name()
|
||
|
|
}
|
||
|
|
|
||
|
|
func (c Call) file() string {
|
||
|
|
if c.fn == nil {
|
||
|
|
return "???"
|
||
|
|
}
|
||
|
|
file, _ := c.fn.FileLine(c.pc)
|
||
|
|
return file
|
||
|
|
}
|
||
|
|
|
||
|
|
func (c Call) line() int {
|
||
|
|
if c.fn == nil {
|
||
|
|
return 0
|
||
|
|
}
|
||
|
|
_, line := c.fn.FileLine(c.pc)
|
||
|
|
return line
|
||
|
|
}
|
||
|
|
|
||
|
|
// CallStack records a sequence of function invocations from a goroutine
|
||
|
|
// stack.
|
||
|
|
type CallStack []Call
|
||
|
|
|
||
|
|
// String implements fmt.Stinger. It is equivalent to fmt.Sprintf("%v", cs).
|
||
|
|
func (cs CallStack) String() string {
|
||
|
|
return fmt.Sprint(cs)
|
||
|
|
}
|
||
|
|
|
||
|
|
var (
|
||
|
|
openBracketBytes = []byte("[")
|
||
|
|
closeBracketBytes = []byte("]")
|
||
|
|
spaceBytes = []byte(" ")
|
||
|
|
)
|
||
|
|
|
||
|
|
// MarshalText implements encoding.TextMarshaler. It formats the CallStack the
|
||
|
|
// same as fmt.Sprintf("%v", cs).
|
||
|
|
func (cs CallStack) MarshalText() ([]byte, error) {
|
||
|
|
buf := bytes.Buffer{}
|
||
|
|
buf.Write(openBracketBytes)
|
||
|
|
for i, pc := range cs {
|
||
|
|
if pc.fn == nil {
|
||
|
|
return nil, ErrNoFunc
|
||
|
|
}
|
||
|
|
if i > 0 {
|
||
|
|
buf.Write(spaceBytes)
|
||
|
|
}
|
||
|
|
fmt.Fprint(&buf, pc)
|
||
|
|
}
|
||
|
|
buf.Write(closeBracketBytes)
|
||
|
|
return buf.Bytes(), nil
|
||
|
|
}
|
||
|
|
|
||
|
|
// Format implements fmt.Formatter by printing the CallStack as square brackets
|
||
|
|
// ([, ]) surrounding a space separated list of Calls each formatted with the
|
||
|
|
// supplied verb and options.
|
||
|
|
func (cs CallStack) Format(s fmt.State, verb rune) {
|
||
|
|
s.Write(openBracketBytes)
|
||
|
|
for i, pc := range cs {
|
||
|
|
if i > 0 {
|
||
|
|
s.Write(spaceBytes)
|
||
|
|
}
|
||
|
|
pc.Format(s, verb)
|
||
|
|
}
|
||
|
|
s.Write(closeBracketBytes)
|
||
|
|
}
|
||
|
|
|
||
|
|
// Trace returns a CallStack for the current goroutine with element 0
|
||
|
|
// identifying the calling function.
|
||
|
|
func Trace() CallStack {
|
||
|
|
var pcs [512]uintptr
|
||
|
|
n := runtime.Callers(2, pcs[:])
|
||
|
|
cs := make([]Call, n)
|
||
|
|
|
||
|
|
for i, pc := range pcs[:n] {
|
||
|
|
pcFix := pc
|
||
|
|
if i > 0 && cs[i-1].fn.Name() != "runtime.sigpanic" {
|
||
|
|
pcFix--
|
||
|
|
}
|
||
|
|
cs[i] = Call{
|
||
|
|
fn: runtime.FuncForPC(pcFix),
|
||
|
|
pc: pcFix,
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
return cs
|
||
|
|
}
|
||
|
|
|
||
|
|
// TrimBelow returns a slice of the CallStack with all entries below c
|
||
|
|
// removed.
|
||
|
|
func (cs CallStack) TrimBelow(c Call) CallStack {
|
||
|
|
for len(cs) > 0 && cs[0].pc != c.pc {
|
||
|
|
cs = cs[1:]
|
||
|
|
}
|
||
|
|
return cs
|
||
|
|
}
|
||
|
|
|
||
|
|
// TrimAbove returns a slice of the CallStack with all entries above c
|
||
|
|
// removed.
|
||
|
|
func (cs CallStack) TrimAbove(c Call) CallStack {
|
||
|
|
for len(cs) > 0 && cs[len(cs)-1].pc != c.pc {
|
||
|
|
cs = cs[:len(cs)-1]
|
||
|
|
}
|
||
|
|
return cs
|
||
|
|
}
|
||
|
|
|
||
|
|
// pkgIndex returns the index that results in file[index:] being the path of
|
||
|
|
// file relative to the compile time GOPATH, and file[:index] being the
|
||
|
|
// $GOPATH/src/ portion of file. funcName must be the name of a function in
|
||
|
|
// file as returned by runtime.Func.Name.
|
||
|
|
func pkgIndex(file, funcName string) int {
|
||
|
|
// As of Go 1.6.2 there is no direct way to know the compile time GOPATH
|
||
|
|
// at runtime, but we can infer the number of path segments in the GOPATH.
|
||
|
|
// We note that runtime.Func.Name() returns the function name qualified by
|
||
|
|
// the import path, which does not include the GOPATH. Thus we can trim
|
||
|
|
// segments from the beginning of the file path until the number of path
|
||
|
|
// separators remaining is one more than the number of path separators in
|
||
|
|
// the function name. For example, given:
|
||
|
|
//
|
||
|
|
// GOPATH /home/user
|
||
|
|
// file /home/user/src/pkg/sub/file.go
|
||
|
|
// fn.Name() pkg/sub.Type.Method
|
||
|
|
//
|
||
|
|
// We want to produce:
|
||
|
|
//
|
||
|
|
// file[:idx] == /home/user/src/
|
||
|
|
// file[idx:] == pkg/sub/file.go
|
||
|
|
//
|
||
|
|
// From this we can easily see that fn.Name() has one less path separator
|
||
|
|
// than our desired result for file[idx:]. We count separators from the
|
||
|
|
// end of the file path until it finds two more than in the function name
|
||
|
|
// and then move one character forward to preserve the initial path
|
||
|
|
// segment without a leading separator.
|
||
|
|
const sep = "/"
|
||
|
|
i := len(file)
|
||
|
|
for n := strings.Count(funcName, sep) + 2; n > 0; n-- {
|
||
|
|
i = strings.LastIndex(file[:i], sep)
|
||
|
|
if i == -1 {
|
||
|
|
i = -len(sep)
|
||
|
|
break
|
||
|
|
}
|
||
|
|
}
|
||
|
|
// get back to 0 or trim the leading separator
|
||
|
|
return i + len(sep)
|
||
|
|
}
|
||
|
|
|
||
|
|
var runtimePath string
|
||
|
|
|
||
|
|
func init() {
|
||
|
|
var pcs [1]uintptr
|
||
|
|
runtime.Callers(0, pcs[:])
|
||
|
|
fn := runtime.FuncForPC(pcs[0])
|
||
|
|
file, _ := fn.FileLine(pcs[0])
|
||
|
|
|
||
|
|
idx := pkgIndex(file, fn.Name())
|
||
|
|
|
||
|
|
runtimePath = file[:idx]
|
||
|
|
if runtime.GOOS == "windows" {
|
||
|
|
runtimePath = strings.ToLower(runtimePath)
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
func inGoroot(c Call) bool {
|
||
|
|
file := c.file()
|
||
|
|
if len(file) == 0 || file[0] == '?' {
|
||
|
|
return true
|
||
|
|
}
|
||
|
|
if runtime.GOOS == "windows" {
|
||
|
|
file = strings.ToLower(file)
|
||
|
|
}
|
||
|
|
return strings.HasPrefix(file, runtimePath) || strings.HasSuffix(file, "/_testmain.go")
|
||
|
|
}
|
||
|
|
|
||
|
|
// TrimRuntime returns a slice of the CallStack with the topmost entries from
|
||
|
|
// the go runtime removed. It considers any calls originating from unknown
|
||
|
|
// files, files under GOROOT, or _testmain.go as part of the runtime.
|
||
|
|
func (cs CallStack) TrimRuntime() CallStack {
|
||
|
|
for len(cs) > 0 && inGoroot(cs[len(cs)-1]) {
|
||
|
|
cs = cs[:len(cs)-1]
|
||
|
|
}
|
||
|
|
return cs
|
||
|
|
}
|