vendor/github.com/hashicorp/go-hclog/stacktrace.go

   1 // Copyright (c) 2016 Uber Technologies, Inc.
   2 //
   3 // Permission is hereby granted, free of charge, to any person obtaining a copy
   4 // of this software and associated documentation files (the "Software"), to deal
   5 // in the Software without restriction, including without limitation the rights
   6 // to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
   7 // copies of the Software, and to permit persons to whom the Software is
   8 // furnished to do so, subject to the following conditions:
   9 //
  10 // The above copyright notice and this permission notice shall be included in
  11 // all copies or substantial portions of the Software.
  12 //
  13 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  14 // IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  15 // FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  16 // AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  17 // LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
  18 // OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
  19 // THE SOFTWARE.
  20
  21 package hclog
  22
  23 import (
  24         "bytes"
  25         "runtime"
  26         "strconv"
  27         "strings"
  28         "sync"
  29 )
  30
  31 var (
  32         _stacktraceIgnorePrefixes = []string{
  33                 "runtime.goexit",
  34                 "runtime.main",
  35         }
  36         _stacktracePool = sync.Pool{
  37                 New: func() interface{} {
  38                         return newProgramCounters(64)
  39                 },
  40         }
  41 )
  42
  43 // A stacktrace gathered by a previous call to log.Stacktrace. If passed
  44 // to a logging function, the stacktrace will be appended.
  45 type CapturedStacktrace string
  46
  47 // Gather a stacktrace of the current goroutine and return it to be passed
  48 // to a logging function.
  49 func Stacktrace() CapturedStacktrace {
  50         return CapturedStacktrace(takeStacktrace())
  51 }
  52
  53 func takeStacktrace() string {
  54         programCounters := _stacktracePool.Get().(*programCounters)
  55         defer _stacktracePool.Put(programCounters)
  56
  57         var buffer bytes.Buffer
  58
  59         for {
  60                 // Skip the call to runtime.Counters and takeStacktrace so that the
  61                 // program counters start at the caller of takeStacktrace.
  62                 n := runtime.Callers(2, programCounters.pcs)
  63                 if n < cap(programCounters.pcs) {
  64                         programCounters.pcs = programCounters.pcs[:n]
  65                         break
  66                 }
  67                 // Don't put the too-short counter slice back into the pool; this lets
  68                 // the pool adjust if we consistently take deep stacktraces.
  69                 programCounters = newProgramCounters(len(programCounters.pcs) * 2)
  70         }
  71
  72         i := 0
  73         frames := runtime.CallersFrames(programCounters.pcs)
  74         for frame, more := frames.Next(); more; frame, more = frames.Next() {
  75                 if shouldIgnoreStacktraceFunction(frame.Function) {
  76                         continue
  77                 }
  78                 if i != 0 {
  79                         buffer.WriteByte('\n')
  80                 }
  81                 i++
  82                 buffer.WriteString(frame.Function)
  83                 buffer.WriteByte('\n')
  84                 buffer.WriteByte('\t')
  85                 buffer.WriteString(frame.File)
  86                 buffer.WriteByte(':')
  87                 buffer.WriteString(strconv.Itoa(int(frame.Line)))
  88         }
  89
  90         return buffer.String()
  91 }
  92
  93 func shouldIgnoreStacktraceFunction(function string) bool {
  94         for _, prefix := range _stacktraceIgnorePrefixes {
  95                 if strings.HasPrefix(function, prefix) {
  96                         return true
  97                 }
  98         }
  99         return false
 100 }
 101
 102 type programCounters struct {
 103         pcs []uintptr
 104 }
 105
 106 func newProgramCounters(size int) *programCounters {
 107         return &programCounters{make([]uintptr, size)}
 108 }