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 zap
22 23 import (
24 "fmt"
25 26 "go.uber.org/zap/zapcore"
27 )
28 29 // An Option configures a Logger.
30 type Option interface {
31 apply(*Logger)
32 }
33 34 // optionFunc wraps a func so it satisfies the Option interface.
35 type optionFunc func(*Logger)
36 37 func (f optionFunc) apply(log *Logger) {
38 f(log)
39 }
40 41 // WrapCore wraps or replaces the Logger's underlying zapcore.Core.
42 func WrapCore(f func(zapcore.Core) zapcore.Core) Option {
43 return optionFunc(func(log *Logger) {
44 log.core = f(log.core)
45 })
46 }
47 48 // Hooks registers functions which will be called each time the Logger writes
49 // out an Entry. Repeated use of Hooks is additive.
50 //
51 // Hooks are useful for simple side effects, like capturing metrics for the
52 // number of emitted logs. More complex side effects, including anything that
53 // requires access to the Entry's structured fields, should be implemented as
54 // a zapcore.Core instead. See zapcore.RegisterHooks for details.
55 func Hooks(hooks ...func(zapcore.Entry) error) Option {
56 return optionFunc(func(log *Logger) {
57 log.core = zapcore.RegisterHooks(log.core, hooks...)
58 })
59 }
60 61 // Fields adds fields to the Logger.
62 func Fields(fs ...Field) Option {
63 return optionFunc(func(log *Logger) {
64 log.core = log.core.With(fs)
65 })
66 }
67 68 // ErrorOutput sets the destination for errors generated by the Logger. Note
69 // that this option only affects internal errors; for sample code that sends
70 // error-level logs to a different location from info- and debug-level logs,
71 // see the package-level AdvancedConfiguration example.
72 //
73 // The supplied WriteSyncer must be safe for concurrent use. The Open and
74 // zapcore.Lock functions are the simplest ways to protect files with a mutex.
75 func ErrorOutput(w zapcore.WriteSyncer) Option {
76 return optionFunc(func(log *Logger) {
77 log.errorOutput = w
78 })
79 }
80 81 // Development puts the logger in development mode, which makes DPanic-level
82 // logs panic instead of simply logging an error.
83 func Development() Option {
84 return optionFunc(func(log *Logger) {
85 log.development = true
86 })
87 }
88 89 // AddCaller configures the Logger to annotate each message with the filename,
90 // line number, and function name of zap's caller. See also WithCaller.
91 func AddCaller() Option {
92 return WithCaller(true)
93 }
94 95 // WithCaller configures the Logger to annotate each message with the filename,
96 // line number, and function name of zap's caller, or not, depending on the
97 // value of enabled. This is a generalized form of AddCaller.
98 func WithCaller(enabled bool) Option {
99 return optionFunc(func(log *Logger) {
100 log.addCaller = enabled
101 })
102 }
103 104 // AddCallerSkip increases the number of callers skipped by caller annotation
105 // (as enabled by the AddCaller option). When building wrappers around the
106 // Logger and SugaredLogger, supplying this Option prevents zap from always
107 // reporting the wrapper code as the caller.
108 func AddCallerSkip(skip int) Option {
109 return optionFunc(func(log *Logger) {
110 log.callerSkip += skip
111 })
112 }
113 114 // AddStacktrace configures the Logger to record a stack trace for all messages at
115 // or above a given level.
116 func AddStacktrace(lvl zapcore.LevelEnabler) Option {
117 return optionFunc(func(log *Logger) {
118 log.addStack = lvl
119 })
120 }
121 122 // IncreaseLevel increase the level of the logger. It has no effect if
123 // the passed in level tries to decrease the level of the logger.
124 func IncreaseLevel(lvl zapcore.LevelEnabler) Option {
125 return optionFunc(func(log *Logger) {
126 core, err := zapcore.NewIncreaseLevelCore(log.core, lvl)
127 if err != nil {
128 fmt.Fprintf(log.errorOutput, "failed to IncreaseLevel: %v\n", err)
129 } else {
130 log.core = core
131 }
132 })
133 }
134 135 // WithPanicHook sets a CheckWriteHook to run on Panic/DPanic logs.
136 // Zap will call this hook after writing a log statement with a Panic/DPanic level.
137 //
138 // For example, the following builds a logger that will exit the current
139 // goroutine after writing a Panic/DPanic log message, but it will not start a panic.
140 //
141 // zap.New(core, zap.WithPanicHook(zapcore.WriteThenGoexit))
142 //
143 // This is useful for testing Panic/DPanic log output.
144 func WithPanicHook(hook zapcore.CheckWriteHook) Option {
145 return optionFunc(func(log *Logger) {
146 log.onPanic = hook
147 })
148 }
149 150 // OnFatal sets the action to take on fatal logs.
151 //
152 // Deprecated: Use [WithFatalHook] instead.
153 func OnFatal(action zapcore.CheckWriteAction) Option {
154 return WithFatalHook(action)
155 }
156 157 // WithFatalHook sets a CheckWriteHook to run on fatal logs.
158 // Zap will call this hook after writing a log statement with a Fatal level.
159 //
160 // For example, the following builds a logger that will exit the current
161 // goroutine after writing a fatal log message, but it will not exit the
162 // program.
163 //
164 // zap.New(core, zap.WithFatalHook(zapcore.WriteThenGoexit))
165 //
166 // It is important that the provided CheckWriteHook stops the control flow at
167 // the current statement to meet expectations of callers of the logger.
168 // We recommend calling os.Exit or runtime.Goexit inside custom hooks at
169 // minimum.
170 func WithFatalHook(hook zapcore.CheckWriteHook) Option {
171 return optionFunc(func(log *Logger) {
172 log.onFatal = hook
173 })
174 }
175 176 // WithClock specifies the clock used by the logger to determine the current
177 // time for logged entries. Defaults to the system clock with time.Now.
178 func WithClock(clock zapcore.Clock) Option {
179 return optionFunc(func(log *Logger) {
180 log.clock = clock
181 })
182 }
183