401 lines
9.8 KiB
Go
401 lines
9.8 KiB
Go
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// Copyright 2013, Örjan Persson. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package logging
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import (
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"bytes"
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"errors"
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"fmt"
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"io"
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"os"
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"path"
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"path/filepath"
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"regexp"
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"runtime"
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"strings"
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"sync"
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"time"
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)
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// TODO see Formatter interface in fmt/print.go
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// TODO try text/template, maybe it have enough performance
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// TODO other template systems?
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// TODO make it possible to specify formats per backend?
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type fmtVerb int
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const (
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fmtVerbTime fmtVerb = iota
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fmtVerbLevel
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fmtVerbID
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fmtVerbPid
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fmtVerbProgram
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fmtVerbModule
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fmtVerbMessage
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fmtVerbLongfile
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fmtVerbShortfile
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fmtVerbLongpkg
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fmtVerbShortpkg
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fmtVerbLongfunc
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fmtVerbShortfunc
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fmtVerbCallpath
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fmtVerbLevelColor
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// Keep last, there are no match for these below.
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fmtVerbUnknown
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fmtVerbStatic
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)
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var fmtVerbs = []string{
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"time",
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"level",
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"id",
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"pid",
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"program",
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"module",
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"message",
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"longfile",
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"shortfile",
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"longpkg",
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"shortpkg",
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"longfunc",
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"shortfunc",
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"callpath",
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"color",
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}
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const rfc3339Milli = "2006-01-02T15:04:05.999Z07:00"
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var defaultVerbsLayout = []string{
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rfc3339Milli,
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"s",
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"d",
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"d",
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"s",
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"s",
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"s",
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"s",
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"s",
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"s",
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"s",
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"s",
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"s",
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"s",
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"",
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}
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var (
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pid = os.Getpid()
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program = filepath.Base(os.Args[0])
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)
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func getFmtVerbByName(name string) fmtVerb {
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for i, verb := range fmtVerbs {
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if name == verb {
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return fmtVerb(i)
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}
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}
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return fmtVerbUnknown
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}
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// Formatter is the required interface for a custom log record formatter.
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type Formatter interface {
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Format(calldepth int, r *Record, w io.Writer) error
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}
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// formatter is used by all backends unless otherwise overriden.
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var formatter struct {
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sync.RWMutex
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def Formatter
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}
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func getFormatter() Formatter {
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formatter.RLock()
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defer formatter.RUnlock()
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return formatter.def
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}
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var (
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// DefaultFormatter is the default formatter used and is only the message.
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DefaultFormatter = MustStringFormatter("%{message}")
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// GlogFormatter mimics the glog format
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GlogFormatter = MustStringFormatter("%{level:.1s}%{time:0102 15:04:05.999999} %{pid} %{shortfile}] %{message}")
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)
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// SetFormatter sets the default formatter for all new backends. A backend will
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// fetch this value once it is needed to format a record. Note that backends
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// will cache the formatter after the first point. For now, make sure to set
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// the formatter before logging.
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func SetFormatter(f Formatter) {
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formatter.Lock()
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defer formatter.Unlock()
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formatter.def = f
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}
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var formatRe = regexp.MustCompile(`%{([a-z]+)(?::(.*?[^\\]))?}`)
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type part struct {
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verb fmtVerb
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layout string
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}
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// stringFormatter contains a list of parts which explains how to build the
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// formatted string passed on to the logging backend.
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type stringFormatter struct {
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parts []part
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}
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// NewStringFormatter returns a new Formatter which outputs the log record as a
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// string based on the 'verbs' specified in the format string.
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//
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// The verbs:
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//
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// General:
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// %{id} Sequence number for log message (uint64).
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// %{pid} Process id (int)
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// %{time} Time when log occurred (time.Time)
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// %{level} Log level (Level)
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// %{module} Module (string)
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// %{program} Basename of os.Args[0] (string)
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// %{message} Message (string)
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// %{longfile} Full file name and line number: /a/b/c/d.go:23
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// %{shortfile} Final file name element and line number: d.go:23
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// %{callpath} Callpath like main.a.b.c...c "..." meaning recursive call
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// %{color} ANSI color based on log level
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//
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// For normal types, the output can be customized by using the 'verbs' defined
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// in the fmt package, eg. '%{id:04d}' to make the id output be '%04d' as the
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// format string.
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//
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// For time.Time, use the same layout as time.Format to change the time format
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// when output, eg "2006-01-02T15:04:05.999Z-07:00".
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//
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// For the 'color' verb, the output can be adjusted to either use bold colors,
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// i.e., '%{color:bold}' or to reset the ANSI attributes, i.e.,
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// '%{color:reset}' Note that if you use the color verb explicitly, be sure to
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// reset it or else the color state will persist past your log message. e.g.,
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// "%{color:bold}%{time:15:04:05} %{level:-8s}%{color:reset} %{message}" will
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// just colorize the time and level, leaving the message uncolored.
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//
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// Colors on Windows is unfortunately not supported right now and is currently
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// a no-op.
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//
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// There's also a couple of experimental 'verbs'. These are exposed to get
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// feedback and needs a bit of tinkering. Hence, they might change in the
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// future.
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//
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// Experimental:
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// %{longpkg} Full package path, eg. github.com/go-logging
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// %{shortpkg} Base package path, eg. go-logging
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// %{longfunc} Full function name, eg. littleEndian.PutUint32
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// %{shortfunc} Base function name, eg. PutUint32
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// %{callpath} Call function path, eg. main.a.b.c
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func NewStringFormatter(format string) (Formatter, error) {
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var fmter = &stringFormatter{}
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// Find the boundaries of all %{vars}
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matches := formatRe.FindAllStringSubmatchIndex(format, -1)
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if matches == nil {
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return nil, errors.New("logger: invalid log format: " + format)
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}
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// Collect all variables and static text for the format
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prev := 0
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for _, m := range matches {
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start, end := m[0], m[1]
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if start > prev {
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fmter.add(fmtVerbStatic, format[prev:start])
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}
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name := format[m[2]:m[3]]
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verb := getFmtVerbByName(name)
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if verb == fmtVerbUnknown {
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return nil, errors.New("logger: unknown variable: " + name)
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}
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// Handle layout customizations or use the default. If this is not for the
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// time or color formatting, we need to prefix with %.
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layout := defaultVerbsLayout[verb]
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if m[4] != -1 {
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layout = format[m[4]:m[5]]
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}
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if verb != fmtVerbTime && verb != fmtVerbLevelColor {
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layout = "%" + layout
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}
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fmter.add(verb, layout)
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prev = end
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}
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end := format[prev:]
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if end != "" {
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fmter.add(fmtVerbStatic, end)
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}
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// Make a test run to make sure we can format it correctly.
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t, err := time.Parse(time.RFC3339, "2010-02-04T21:00:57-08:00")
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if err != nil {
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panic(err)
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}
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r := &Record{
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Id: 12345,
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Time: t,
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Module: "logger",
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Args: []interface{}{"go"},
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fmt: "hello %s",
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}
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if err := fmter.Format(0, r, &bytes.Buffer{}); err != nil {
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return nil, err
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}
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return fmter, nil
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}
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// MustStringFormatter is equivalent to NewStringFormatter with a call to panic
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// on error.
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func MustStringFormatter(format string) Formatter {
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f, err := NewStringFormatter(format)
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if err != nil {
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panic("Failed to initialized string formatter: " + err.Error())
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}
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return f
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}
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func (f *stringFormatter) add(verb fmtVerb, layout string) {
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f.parts = append(f.parts, part{verb, layout})
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}
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func (f *stringFormatter) Format(calldepth int, r *Record, output io.Writer) error {
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for _, part := range f.parts {
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if part.verb == fmtVerbStatic {
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output.Write([]byte(part.layout))
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} else if part.verb == fmtVerbTime {
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output.Write([]byte(r.Time.Format(part.layout)))
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} else if part.verb == fmtVerbLevelColor {
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doFmtVerbLevelColor(part.layout, r.Level, output)
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} else {
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var v interface{}
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switch part.verb {
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case fmtVerbLevel:
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v = r.Level
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break
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case fmtVerbID:
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v = r.Id
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break
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case fmtVerbPid:
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v = pid
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break
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case fmtVerbProgram:
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v = program
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break
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case fmtVerbModule:
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v = r.Module
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break
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case fmtVerbMessage:
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v = r.Message()
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break
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case fmtVerbLongfile, fmtVerbShortfile:
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_, file, line, ok := runtime.Caller(calldepth + 1)
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if !ok {
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file = "???"
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line = 0
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} else if part.verb == fmtVerbShortfile {
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file = filepath.Base(file)
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}
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v = fmt.Sprintf("%s:%d", file, line)
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case fmtVerbLongfunc, fmtVerbShortfunc,
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fmtVerbLongpkg, fmtVerbShortpkg:
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// TODO cache pc
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v = "???"
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if pc, _, _, ok := runtime.Caller(calldepth + 1); ok {
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if f := runtime.FuncForPC(pc); f != nil {
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v = formatFuncName(part.verb, f.Name())
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}
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}
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case fmtVerbCallpath:
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v = formatCallpath(calldepth + 1)
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default:
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panic("unhandled format part")
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}
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fmt.Fprintf(output, part.layout, v)
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}
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}
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return nil
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}
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// formatFuncName tries to extract certain part of the runtime formatted
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// function name to some pre-defined variation.
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//
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// This function is known to not work properly if the package path or name
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// contains a dot.
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func formatFuncName(v fmtVerb, f string) string {
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i := strings.LastIndex(f, "/")
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j := strings.Index(f[i+1:], ".")
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if j < 1 {
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return "???"
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}
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pkg, fun := f[:i+j+1], f[i+j+2:]
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switch v {
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case fmtVerbLongpkg:
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return pkg
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case fmtVerbShortpkg:
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return path.Base(pkg)
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case fmtVerbLongfunc:
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return fun
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case fmtVerbShortfunc:
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i = strings.LastIndex(fun, ".")
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return fun[i+1:]
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}
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panic("unexpected func formatter")
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}
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func formatCallpath(calldepth int) string {
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v := ""
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callers := make([]uintptr, 64)
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n := runtime.Callers(calldepth+2, callers)
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oldPc := callers[n-1]
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recursiveCall := false
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for i := n - 3; i >= 0; i-- {
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pc := callers[i]
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if oldPc == pc {
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recursiveCall = true
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continue
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}
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oldPc = pc
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if recursiveCall {
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recursiveCall = false
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v += ".."
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}
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if i < n-3 {
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v += "."
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}
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if f := runtime.FuncForPC(pc); f != nil {
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v += formatFuncName(fmtVerbShortfunc, f.Name())
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}
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}
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return v
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}
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// backendFormatter combines a backend with a specific formatter making it
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// possible to have different log formats for different backends.
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|
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type backendFormatter struct {
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|
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b Backend
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f Formatter
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}
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// NewBackendFormatter creates a new backend which makes all records that
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// passes through it beeing formatted by the specific formatter.
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func NewBackendFormatter(b Backend, f Formatter) Backend {
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return &backendFormatter{b, f}
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}
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// Log implements the Log function required by the Backend interface.
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func (bf *backendFormatter) Log(level Level, calldepth int, r *Record) error {
|
||
|
|
// Make a shallow copy of the record and replace any formatter
|
||
|
|
r2 := *r
|
||
|
|
r2.formatter = bf.f
|
||
|
|
return bf.b.Log(level, calldepth+1, &r2)
|
||
|
|
}
|