forked from TrueCloudLab/restic
175 lines
3.1 KiB
Go
175 lines
3.1 KiB
Go
// +build debug
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package debug
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import (
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"fmt"
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"log"
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"os"
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"path"
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"path/filepath"
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"runtime"
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"strconv"
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"strings"
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"sync"
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"syscall"
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)
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var opts struct {
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logger *log.Logger
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tags map[string]bool
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m sync.Mutex
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}
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// make sure that all the initialization happens before the init() functions
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// are called, cf https://golang.org/ref/spec#Package_initialization
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var _ = initDebug()
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func initDebug() bool {
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initDebugLogger()
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initDebugTags()
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fmt.Fprintf(os.Stderr, "debug enabled\n")
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return true
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}
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func initDebugLogger() {
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debugfile := os.Getenv("DEBUG_LOG")
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if debugfile == "" {
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return
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}
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fmt.Fprintf(os.Stderr, "debug log file %v\n", debugfile)
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f, err := os.OpenFile(debugfile, os.O_WRONLY|os.O_APPEND, 0600)
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if err == nil {
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_, err = f.Seek(2, 0)
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if err != nil {
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fmt.Fprintf(os.Stderr, "unable to seek to the end of %v: %v\n", debugfile, err)
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os.Exit(3)
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}
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}
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if err != nil && os.IsNotExist(err) {
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f, err = os.OpenFile(debugfile, os.O_WRONLY|os.O_CREATE, 0600)
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}
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if err != nil {
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fmt.Fprintf(os.Stderr, "unable to open debug log file: %v\n", err)
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os.Exit(2)
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}
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opts.logger = log.New(f, "", log.LstdFlags)
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}
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func initDebugTags() {
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opts.tags = make(map[string]bool)
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// defaults
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opts.tags["break"] = true
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// initialize tags
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env := os.Getenv("DEBUG_TAGS")
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if len(env) == 0 {
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return
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}
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tags := []string{}
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for _, tag := range strings.Split(env, ",") {
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t := strings.TrimSpace(tag)
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val := true
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if t[0] == '-' {
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val = false
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t = t[1:]
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} else if t[0] == '+' {
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val = true
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t = t[1:]
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}
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// test pattern
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_, err := path.Match(t, "")
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if err != nil {
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fmt.Fprintf(os.Stderr, "error: invalid pattern %q: %v\n", t, err)
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os.Exit(5)
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}
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opts.tags[t] = val
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tags = append(tags, tag)
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}
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fmt.Fprintf(os.Stderr, "debug log enabled for: %v\n", tags)
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}
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// taken from https://github.com/VividCortex/trace
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func goroutineNum() int {
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b := make([]byte, 20)
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runtime.Stack(b, false)
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var num int
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fmt.Sscanf(string(b), "goroutine %d ", &num)
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return num
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}
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// taken from https://github.com/VividCortex/trace
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func getPosition() string {
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_, file, line, ok := runtime.Caller(2)
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if !ok {
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return ""
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}
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goroutine := goroutineNum()
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return fmt.Sprintf("%3d %s:%3d", goroutine, filepath.Base(file), line)
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}
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var maxTagLen = 10
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func Log(tag string, f string, args ...interface{}) {
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opts.m.Lock()
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defer opts.m.Unlock()
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if f[len(f)-1] != '\n' {
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f += "\n"
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}
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if len(tag) > maxTagLen {
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maxTagLen = len(tag)
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}
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formatStringTag := "[%" + strconv.FormatInt(int64(maxTagLen), 10) + "s]"
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formatString := fmt.Sprintf(formatStringTag+" %s %s", tag, getPosition(), f)
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dbgprint := func() {
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fmt.Fprintf(os.Stderr, formatString, args...)
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}
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if opts.logger != nil {
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opts.logger.Printf(formatString, args...)
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}
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// check if tag is enabled directly
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if v, ok := opts.tags[tag]; ok {
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if v {
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dbgprint()
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}
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return
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}
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// check for globbing
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for k, v := range opts.tags {
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if m, _ := path.Match(k, tag); m {
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if v {
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dbgprint()
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}
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return
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}
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}
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// check if tag "all" is enabled
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if v, ok := opts.tags["all"]; ok && v {
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dbgprint()
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}
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}
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