source: code/trunk/vendor/github.com/sirupsen/logrus/entry.go@ 67

package logrus

import (
        "bytes"
        "context"
        "fmt"
        "os"
        "reflect"
        "runtime"
        "strings"
        "sync"
        "time"
)

var (

        // qualified package name, cached at first use
        logrusPackage string

        // Positions in the call stack when tracing to report the calling method
        minimumCallerDepth int

        // Used for caller information initialisation
        callerInitOnce sync.Once
)

const (
        maximumCallerDepth int = 25
        knownLogrusFrames  int = 4
)

func init() {
        // start at the bottom of the stack before the package-name cache is primed
        minimumCallerDepth = 1
}

// Defines the key when adding errors using WithError.
var ErrorKey = "error"

// An entry is the final or intermediate Logrus logging entry. It contains all
// the fields passed with WithField{,s}. It's finally logged when Trace, Debug,
// Info, Warn, Error, Fatal or Panic is called on it. These objects can be
// reused and passed around as much as you wish to avoid field duplication.
type Entry struct {
        Logger *Logger

        // Contains all the fields set by the user.
        Data Fields

        // Time at which the log entry was created
        Time time.Time

        // Level the log entry was logged at: Trace, Debug, Info, Warn, Error, Fatal or Panic
        // This field will be set on entry firing and the value will be equal to the one in Logger struct field.
        Level Level

        // Calling method, with package name
        Caller *runtime.Frame

        // Message passed to Trace, Debug, Info, Warn, Error, Fatal or Panic
        Message string

        // When formatter is called in entry.log(), a Buffer may be set to entry
        Buffer *bytes.Buffer

        // Contains the context set by the user. Useful for hook processing etc.
        Context context.Context

        // err may contain a field formatting error
        err string
}

func NewEntry(logger *Logger) *Entry {
        return &Entry{
                Logger: logger,
                // Default is three fields, plus one optional.  Give a little extra room.
                Data: make(Fields, 6),
        }
}

func (entry *Entry) Dup() *Entry {
        data := make(Fields, len(entry.Data))
        for k, v := range entry.Data {
                data[k] = v
        }
        return &Entry{Logger: entry.Logger, Data: data, Time: entry.Time, Context: entry.Context, err: entry.err}
}

// Returns the bytes representation of this entry from the formatter.
func (entry *Entry) Bytes() ([]byte, error) {
        return entry.Logger.Formatter.Format(entry)
}

// Returns the string representation from the reader and ultimately the
// formatter.
func (entry *Entry) String() (string, error) {
        serialized, err := entry.Bytes()
        if err != nil {
                return "", err
        }
        str := string(serialized)
        return str, nil
}

// Add an error as single field (using the key defined in ErrorKey) to the Entry.
func (entry *Entry) WithError(err error) *Entry {
        return entry.WithField(ErrorKey, err)
}

// Add a context to the Entry.
func (entry *Entry) WithContext(ctx context.Context) *Entry {
        dataCopy := make(Fields, len(entry.Data))
        for k, v := range entry.Data {
                dataCopy[k] = v
        }
        return &Entry{Logger: entry.Logger, Data: dataCopy, Time: entry.Time, err: entry.err, Context: ctx}
}

// Add a single field to the Entry.
func (entry *Entry) WithField(key string, value interface{}) *Entry {
        return entry.WithFields(Fields{key: value})
}

// Add a map of fields to the Entry.
func (entry *Entry) WithFields(fields Fields) *Entry {
        data := make(Fields, len(entry.Data)+len(fields))
        for k, v := range entry.Data {
                data[k] = v
        }
        fieldErr := entry.err
        for k, v := range fields {
                isErrField := false
                if t := reflect.TypeOf(v); t != nil {
                        switch {
                        case t.Kind() == reflect.Func, t.Kind() == reflect.Ptr && t.Elem().Kind() == reflect.Func:
                                isErrField = true
                        }
                }
                if isErrField {
                        tmp := fmt.Sprintf("can not add field %q", k)
                        if fieldErr != "" {
                                fieldErr = entry.err + ", " + tmp
                        } else {
                                fieldErr = tmp
                        }
                } else {
                        data[k] = v
                }
        }
        return &Entry{Logger: entry.Logger, Data: data, Time: entry.Time, err: fieldErr, Context: entry.Context}
}

// Overrides the time of the Entry.
func (entry *Entry) WithTime(t time.Time) *Entry {
        dataCopy := make(Fields, len(entry.Data))
        for k, v := range entry.Data {
                dataCopy[k] = v
        }
        return &Entry{Logger: entry.Logger, Data: dataCopy, Time: t, err: entry.err, Context: entry.Context}
}

// getPackageName reduces a fully qualified function name to the package name
// There really ought to be to be a better way...
func getPackageName(f string) string {
        for {
                lastPeriod := strings.LastIndex(f, ".")
                lastSlash := strings.LastIndex(f, "/")
                if lastPeriod > lastSlash {
                        f = f[:lastPeriod]
                } else {
                        break
                }
        }

        return f
}

// getCaller retrieves the name of the first non-logrus calling function
func getCaller() *runtime.Frame {
        // cache this package's fully-qualified name
        callerInitOnce.Do(func() {
                pcs := make([]uintptr, maximumCallerDepth)
                _ = runtime.Callers(0, pcs)

                // dynamic get the package name and the minimum caller depth
                for i := 0; i < maximumCallerDepth; i++ {
                        funcName := runtime.FuncForPC(pcs[i]).Name()
                        if strings.Contains(funcName, "getCaller") {
                                logrusPackage = getPackageName(funcName)
                                break
                        }
                }

                minimumCallerDepth = knownLogrusFrames
        })

        // Restrict the lookback frames to avoid runaway lookups
        pcs := make([]uintptr, maximumCallerDepth)
        depth := runtime.Callers(minimumCallerDepth, pcs)
        frames := runtime.CallersFrames(pcs[:depth])

        for f, again := frames.Next(); again; f, again = frames.Next() {
                pkg := getPackageName(f.Function)

                // If the caller isn't part of this package, we're done
                if pkg != logrusPackage {
                        return &f //nolint:scopelint
                }
        }

        // if we got here, we failed to find the caller's context
        return nil
}

func (entry Entry) HasCaller() (has bool) {
        return entry.Logger != nil &&
                entry.Logger.ReportCaller &&
                entry.Caller != nil
}

func (entry *Entry) log(level Level, msg string) {
        var buffer *bytes.Buffer

        newEntry := entry.Dup()

        if newEntry.Time.IsZero() {
                newEntry.Time = time.Now()
        }

        newEntry.Level = level
        newEntry.Message = msg

        newEntry.Logger.mu.Lock()
        reportCaller := newEntry.Logger.ReportCaller
        bufPool := newEntry.getBufferPool()
        newEntry.Logger.mu.Unlock()

        if reportCaller {
                newEntry.Caller = getCaller()
        }

        newEntry.fireHooks()
        buffer = bufPool.Get()
        defer func() {
                newEntry.Buffer = nil
                buffer.Reset()
                bufPool.Put(buffer)
        }()
        buffer.Reset()
        newEntry.Buffer = buffer

        newEntry.write()

        newEntry.Buffer = nil

        // To avoid Entry#log() returning a value that only would make sense for
        // panic() to use in Entry#Panic(), we avoid the allocation by checking
        // directly here.
        if level <= PanicLevel {
                panic(newEntry)
        }
}

func (entry *Entry) getBufferPool() (pool BufferPool) {
        if entry.Logger.BufferPool != nil {
                return entry.Logger.BufferPool
        }
        return bufferPool
}

func (entry *Entry) fireHooks() {
        var tmpHooks LevelHooks
        entry.Logger.mu.Lock()
        tmpHooks = make(LevelHooks, len(entry.Logger.Hooks))
        for k, v := range entry.Logger.Hooks {
                tmpHooks[k] = v
        }
        entry.Logger.mu.Unlock()

        err := tmpHooks.Fire(entry.Level, entry)
        if err != nil {
                fmt.Fprintf(os.Stderr, "Failed to fire hook: %v\n", err)
        }
}

func (entry *Entry) write() {
        entry.Logger.mu.Lock()
        defer entry.Logger.mu.Unlock()
        serialized, err := entry.Logger.Formatter.Format(entry)
        if err != nil {
                fmt.Fprintf(os.Stderr, "Failed to obtain reader, %v\n", err)
                return
        }
        if _, err := entry.Logger.Out.Write(serialized); err != nil {
                fmt.Fprintf(os.Stderr, "Failed to write to log, %v\n", err)
        }
}

// Log will log a message at the level given as parameter.
// Warning: using Log at Panic or Fatal level will not respectively Panic nor Exit.
// For this behaviour Entry.Panic or Entry.Fatal should be used instead.
func (entry *Entry) Log(level Level, args ...interface{}) {
        if entry.Logger.IsLevelEnabled(level) {
                entry.log(level, fmt.Sprint(args...))
        }
}

func (entry *Entry) Trace(args ...interface{}) {
        entry.Log(TraceLevel, args...)
}

func (entry *Entry) Debug(args ...interface{}) {
        entry.Log(DebugLevel, args...)
}

func (entry *Entry) Print(args ...interface{}) {
        entry.Info(args...)
}

func (entry *Entry) Info(args ...interface{}) {
        entry.Log(InfoLevel, args...)
}

func (entry *Entry) Warn(args ...interface{}) {
        entry.Log(WarnLevel, args...)
}

func (entry *Entry) Warning(args ...interface{}) {
        entry.Warn(args...)
}

func (entry *Entry) Error(args ...interface{}) {
        entry.Log(ErrorLevel, args...)
}

func (entry *Entry) Fatal(args ...interface{}) {
        entry.Log(FatalLevel, args...)
        entry.Logger.Exit(1)
}

func (entry *Entry) Panic(args ...interface{}) {
        entry.Log(PanicLevel, args...)
}

// Entry Printf family functions

func (entry *Entry) Logf(level Level, format string, args ...interface{}) {
        if entry.Logger.IsLevelEnabled(level) {
                entry.Log(level, fmt.Sprintf(format, args...))
        }
}

func (entry *Entry) Tracef(format string, args ...interface{}) {
        entry.Logf(TraceLevel, format, args...)
}

func (entry *Entry) Debugf(format string, args ...interface{}) {
        entry.Logf(DebugLevel, format, args...)
}

func (entry *Entry) Infof(format string, args ...interface{}) {
        entry.Logf(InfoLevel, format, args...)
}

func (entry *Entry) Printf(format string, args ...interface{}) {
        entry.Infof(format, args...)
}

func (entry *Entry) Warnf(format string, args ...interface{}) {
        entry.Logf(WarnLevel, format, args...)
}

func (entry *Entry) Warningf(format string, args ...interface{}) {
        entry.Warnf(format, args...)
}

func (entry *Entry) Errorf(format string, args ...interface{}) {
        entry.Logf(ErrorLevel, format, args...)
}

func (entry *Entry) Fatalf(format string, args ...interface{}) {
        entry.Logf(FatalLevel, format, args...)
        entry.Logger.Exit(1)
}

func (entry *Entry) Panicf(format string, args ...interface{}) {
        entry.Logf(PanicLevel, format, args...)
}

// Entry Println family functions

func (entry *Entry) Logln(level Level, args ...interface{}) {
        if entry.Logger.IsLevelEnabled(level) {
                entry.Log(level, entry.sprintlnn(args...))
        }
}

func (entry *Entry) Traceln(args ...interface{}) {
        entry.Logln(TraceLevel, args...)
}

func (entry *Entry) Debugln(args ...interface{}) {
        entry.Logln(DebugLevel, args...)
}

func (entry *Entry) Infoln(args ...interface{}) {
        entry.Logln(InfoLevel, args...)
}

func (entry *Entry) Println(args ...interface{}) {
        entry.Infoln(args...)
}

func (entry *Entry) Warnln(args ...interface{}) {
        entry.Logln(WarnLevel, args...)
}

func (entry *Entry) Warningln(args ...interface{}) {
        entry.Warnln(args...)
}

func (entry *Entry) Errorln(args ...interface{}) {
        entry.Logln(ErrorLevel, args...)
}

func (entry *Entry) Fatalln(args ...interface{}) {
        entry.Logln(FatalLevel, args...)
        entry.Logger.Exit(1)
}

func (entry *Entry) Panicln(args ...interface{}) {
        entry.Logln(PanicLevel, args...)
}

// Sprintlnn => Sprint no newline. This is to get the behavior of how
// fmt.Sprintln where spaces are always added between operands, regardless of
// their type. Instead of vendoring the Sprintln implementation to spare a
// string allocation, we do the simplest thing.
func (entry *Entry) sprintlnn(args ...interface{}) string {
        msg := fmt.Sprintln(args...)
        return msg[:len(msg)-1]
}