Permalink
306 lines (272 sloc) 9.79 KB
// Copyright (c) 2016 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package zap
import (
"fmt"
"io/ioutil"
"os"
"runtime"
"strings"
"time"
"go.uber.org/zap/zapcore"
)
// A Logger provides fast, leveled, structured logging. All methods are safe
// for concurrent use.
//
// The Logger is designed for contexts in which every microsecond and every
// allocation matters, so its API intentionally favors performance and type
// safety over brevity. For most applications, the SugaredLogger strikes a
// better balance between performance and ergonomics.
type Logger struct {
core zapcore.Core
development bool
name string
errorOutput zapcore.WriteSyncer
addCaller bool
addStack zapcore.LevelEnabler
callerSkip int
}
// New constructs a new Logger from the provided zapcore.Core and Options. If
// the passed zapcore.Core is nil, it falls back to using a no-op
// implementation.
//
// This is the most flexible way to construct a Logger, but also the most
// verbose. For typical use cases, the highly-opinionated presets
// (NewProduction, NewDevelopment, and NewExample) or the Config struct are
// more convenient.
//
// For sample code, see the package-level AdvancedConfiguration example.
func New(core zapcore.Core, options ...Option) *Logger {
if core == nil {
return NewNop()
}
log := &Logger{
core: core,
errorOutput: zapcore.Lock(os.Stderr),
addStack: zapcore.FatalLevel + 1,
}
return log.WithOptions(options...)
}
// NewNop returns a no-op Logger. It never writes out logs or internal errors,
// and it never runs user-defined hooks.
//
// Using WithOptions to replace the Core or error output of a no-op Logger can
// re-enable logging.
func NewNop() *Logger {
return &Logger{
core: zapcore.NewNopCore(),
errorOutput: zapcore.AddSync(ioutil.Discard),
addStack: zapcore.FatalLevel + 1,
}
}
// NewProduction builds a sensible production Logger that writes InfoLevel and
// above logs to standard error as JSON.
//
// It's a shortcut for NewProductionConfig().Build(...Option).
func NewProduction(options ...Option) (*Logger, error) {
return NewProductionConfig().Build(options...)
}
// NewDevelopment builds a development Logger that writes DebugLevel and above
// logs to standard error in a human-friendly format.
//
// It's a shortcut for NewDevelopmentConfig().Build(...Option).
func NewDevelopment(options ...Option) (*Logger, error) {
return NewDevelopmentConfig().Build(options...)
}
// NewExample builds a Logger that's designed for use in zap's testable
// examples. It writes DebugLevel and above logs to standard out as JSON, but
// omits the timestamp and calling function to keep example output
// short and deterministic.
func NewExample(options ...Option) *Logger {
encoderCfg := zapcore.EncoderConfig{
MessageKey: "msg",
LevelKey: "level",
NameKey: "logger",
EncodeLevel: zapcore.LowercaseLevelEncoder,
EncodeTime: zapcore.ISO8601TimeEncoder,
EncodeDuration: zapcore.StringDurationEncoder,
}
core := zapcore.NewCore(zapcore.NewJSONEncoder(encoderCfg), os.Stdout, DebugLevel)
return New(core).WithOptions(options...)
}
// Sugar wraps the Logger to provide a more ergonomic, but slightly slower,
// API. Sugaring a Logger is quite inexpensive, so it's reasonable for a
// single application to use both Loggers and SugaredLoggers, converting
// between them on the boundaries of performance-sensitive code.
func (log *Logger) Sugar() *SugaredLogger {
core := log.clone()
core.callerSkip += 2
return &SugaredLogger{core}
}
// Named adds a new path segment to the logger's name. Segments are joined by
// periods. By default, Loggers are unnamed.
func (log *Logger) Named(s string) *Logger {
if s == "" {
return log
}
l := log.clone()
if log.name == "" {
l.name = s
} else {
l.name = strings.Join([]string{l.name, s}, ".")
}
return l
}
// WithOptions clones the current Logger, applies the supplied Options, and
// returns the resulting Logger. It's safe to use concurrently.
func (log *Logger) WithOptions(opts ...Option) *Logger {
c := log.clone()
for _, opt := range opts {
opt.apply(c)
}
return c
}
// With creates a child logger and adds structured context to it. Fields added
// to the child don't affect the parent, and vice versa.
func (log *Logger) With(fields ...Field) *Logger {
if len(fields) == 0 {
return log
}
l := log.clone()
l.core = l.core.With(fields)
return l
}
// Check returns a CheckedEntry if logging a message at the specified level
// is enabled. It's a completely optional optimization; in high-performance
// applications, Check can help avoid allocating a slice to hold fields.
func (log *Logger) Check(lvl zapcore.Level, msg string) *zapcore.CheckedEntry {
return log.check(lvl, msg)
}
// Debug logs a message at DebugLevel. The message includes any fields passed
// at the log site, as well as any fields accumulated on the logger.
func (log *Logger) Debug(msg string, fields ...Field) {
if ce := log.check(DebugLevel, msg); ce != nil {
ce.Write(fields...)
}
}
// Info logs a message at InfoLevel. The message includes any fields passed
// at the log site, as well as any fields accumulated on the logger.
func (log *Logger) Info(msg string, fields ...Field) {
if ce := log.check(InfoLevel, msg); ce != nil {
ce.Write(fields...)
}
}
// Warn logs a message at WarnLevel. The message includes any fields passed
// at the log site, as well as any fields accumulated on the logger.
func (log *Logger) Warn(msg string, fields ...Field) {
if ce := log.check(WarnLevel, msg); ce != nil {
ce.Write(fields...)
}
}
// Error logs a message at ErrorLevel. The message includes any fields passed
// at the log site, as well as any fields accumulated on the logger.
func (log *Logger) Error(msg string, fields ...Field) {
if ce := log.check(ErrorLevel, msg); ce != nil {
ce.Write(fields...)
}
}
// DPanic logs a message at DPanicLevel. The message includes any fields
// passed at the log site, as well as any fields accumulated on the logger.
//
// If the logger is in development mode, it then panics (DPanic means
// "development panic"). This is useful for catching errors that are
// recoverable, but shouldn't ever happen.
func (log *Logger) DPanic(msg string, fields ...Field) {
if ce := log.check(DPanicLevel, msg); ce != nil {
ce.Write(fields...)
}
}
// Panic logs a message at PanicLevel. The message includes any fields passed
// at the log site, as well as any fields accumulated on the logger.
//
// The logger then panics, even if logging at PanicLevel is disabled.
func (log *Logger) Panic(msg string, fields ...Field) {
if ce := log.check(PanicLevel, msg); ce != nil {
ce.Write(fields...)
}
}
// Fatal logs a message at FatalLevel. The message includes any fields passed
// at the log site, as well as any fields accumulated on the logger.
//
// The logger then calls os.Exit(1), even if logging at FatalLevel is
// disabled.
func (log *Logger) Fatal(msg string, fields ...Field) {
if ce := log.check(FatalLevel, msg); ce != nil {
ce.Write(fields...)
}
}
// Sync calls the underlying Core's Sync method, flushing any buffered log
// entries. Applications should take care to call Sync before exiting.
func (log *Logger) Sync() error {
return log.core.Sync()
}
// Core returns the Logger's underlying zapcore.Core.
func (log *Logger) Core() zapcore.Core {
return log.core
}
func (log *Logger) clone() *Logger {
copy := *log
return &copy
}
func (log *Logger) check(lvl zapcore.Level, msg string) *zapcore.CheckedEntry {
// check must always be called directly by a method in the Logger interface
// (e.g., Check, Info, Fatal).
const callerSkipOffset = 2
// Create basic checked entry thru the core; this will be non-nil if the
// log message will actually be written somewhere.
ent := zapcore.Entry{
LoggerName: log.name,
Time: time.Now(),
Level: lvl,
Message: msg,
}
ce := log.core.Check(ent, nil)
willWrite := ce != nil
// Set up any required terminal behavior.
switch ent.Level {
case zapcore.PanicLevel:
ce = ce.Should(ent, zapcore.WriteThenPanic)
case zapcore.FatalLevel:
ce = ce.Should(ent, zapcore.WriteThenFatal)
case zapcore.DPanicLevel:
if log.development {
ce = ce.Should(ent, zapcore.WriteThenPanic)
}
}
// Only do further annotation if we're going to write this message; checked
// entries that exist only for terminal behavior don't benefit from
// annotation.
if !willWrite {
return ce
}
// Thread the error output through to the CheckedEntry.
ce.ErrorOutput = log.errorOutput
if log.addCaller {
ce.Entry.Caller = zapcore.NewEntryCaller(runtime.Caller(log.callerSkip + callerSkipOffset))
if !ce.Entry.Caller.Defined {
fmt.Fprintf(log.errorOutput, "%v Logger.check error: failed to get caller\n", time.Now().UTC())
log.errorOutput.Sync()
}
}
if log.addStack.Enabled(ce.Entry.Level) {
ce.Entry.Stack = Stack("").String
}
return ce
}