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
21package zap
22
23import (
24	"fmt"
25	"sort"
26	"time"
27
28	"go.uber.org/zap/zapcore"
29)
30
31// SamplingConfig sets a sampling strategy for the logger. Sampling caps the
32// global CPU and I/O load that logging puts on your process while attempting
33// to preserve a representative subset of your logs.
34//
35// If specified, the Sampler will invoke the Hook after each decision.
36//
37// Values configured here are per-second. See zapcore.NewSamplerWithOptions for
38// details.
39type SamplingConfig struct {
40	Initial    int                                           `json:"initial" yaml:"initial"`
41	Thereafter int                                           `json:"thereafter" yaml:"thereafter"`
42	Hook       func(zapcore.Entry, zapcore.SamplingDecision) `json:"-" yaml:"-"`
43}
44
45// Config offers a declarative way to construct a logger. It doesn't do
46// anything that can't be done with New, Options, and the various
47// zapcore.WriteSyncer and zapcore.Core wrappers, but it's a simpler way to
48// toggle common options.
49//
50// Note that Config intentionally supports only the most common options. More
51// unusual logging setups (logging to network connections or message queues,
52// splitting output between multiple files, etc.) are possible, but require
53// direct use of the zapcore package. For sample code, see the package-level
54// BasicConfiguration and AdvancedConfiguration examples.
55//
56// For an example showing runtime log level changes, see the documentation for
57// AtomicLevel.
58type Config struct {
59	// Level is the minimum enabled logging level. Note that this is a dynamic
60	// level, so calling Config.Level.SetLevel will atomically change the log
61	// level of all loggers descended from this config.
62	Level AtomicLevel `json:"level" yaml:"level"`
63	// Development puts the logger in development mode, which changes the
64	// behavior of DPanicLevel and takes stacktraces more liberally.
65	Development bool `json:"development" yaml:"development"`
66	// DisableCaller stops annotating logs with the calling function's file
67	// name and line number. By default, all logs are annotated.
68	DisableCaller bool `json:"disableCaller" yaml:"disableCaller"`
69	// DisableStacktrace completely disables automatic stacktrace capturing. By
70	// default, stacktraces are captured for WarnLevel and above logs in
71	// development and ErrorLevel and above in production.
72	DisableStacktrace bool `json:"disableStacktrace" yaml:"disableStacktrace"`
73	// Sampling sets a sampling policy. A nil SamplingConfig disables sampling.
74	Sampling *SamplingConfig `json:"sampling" yaml:"sampling"`
75	// Encoding sets the logger's encoding. Valid values are "json" and
76	// "console", as well as any third-party encodings registered via
77	// RegisterEncoder.
78	Encoding string `json:"encoding" yaml:"encoding"`
79	// EncoderConfig sets options for the chosen encoder. See
80	// zapcore.EncoderConfig for details.
81	EncoderConfig zapcore.EncoderConfig `json:"encoderConfig" yaml:"encoderConfig"`
82	// OutputPaths is a list of URLs or file paths to write logging output to.
83	// See Open for details.
84	OutputPaths []string `json:"outputPaths" yaml:"outputPaths"`
85	// ErrorOutputPaths is a list of URLs to write internal logger errors to.
86	// The default is standard error.
87	//
88	// Note that this setting only affects internal errors; for sample code that
89	// sends error-level logs to a different location from info- and debug-level
90	// logs, see the package-level AdvancedConfiguration example.
91	ErrorOutputPaths []string `json:"errorOutputPaths" yaml:"errorOutputPaths"`
92	// InitialFields is a collection of fields to add to the root logger.
93	InitialFields map[string]interface{} `json:"initialFields" yaml:"initialFields"`
94}
95
96// NewProductionEncoderConfig returns an opinionated EncoderConfig for
97// production environments.
98func NewProductionEncoderConfig() zapcore.EncoderConfig {
99	return zapcore.EncoderConfig{
100		TimeKey:        "ts",
101		LevelKey:       "level",
102		NameKey:        "logger",
103		CallerKey:      "caller",
104		FunctionKey:    zapcore.OmitKey,
105		MessageKey:     "msg",
106		StacktraceKey:  "stacktrace",
107		LineEnding:     zapcore.DefaultLineEnding,
108		EncodeLevel:    zapcore.LowercaseLevelEncoder,
109		EncodeTime:     zapcore.EpochTimeEncoder,
110		EncodeDuration: zapcore.SecondsDurationEncoder,
111		EncodeCaller:   zapcore.ShortCallerEncoder,
112	}
113}
114
115// NewProductionConfig is a reasonable production logging configuration.
116// Logging is enabled at InfoLevel and above.
117//
118// It uses a JSON encoder, writes to standard error, and enables sampling.
119// Stacktraces are automatically included on logs of ErrorLevel and above.
120func NewProductionConfig() Config {
121	return Config{
122		Level:       NewAtomicLevelAt(InfoLevel),
123		Development: false,
124		Sampling: &SamplingConfig{
125			Initial:    100,
126			Thereafter: 100,
127		},
128		Encoding:         "json",
129		EncoderConfig:    NewProductionEncoderConfig(),
130		OutputPaths:      []string{"stderr"},
131		ErrorOutputPaths: []string{"stderr"},
132	}
133}
134
135// NewDevelopmentEncoderConfig returns an opinionated EncoderConfig for
136// development environments.
137func NewDevelopmentEncoderConfig() zapcore.EncoderConfig {
138	return zapcore.EncoderConfig{
139		// Keys can be anything except the empty string.
140		TimeKey:        "T",
141		LevelKey:       "L",
142		NameKey:        "N",
143		CallerKey:      "C",
144		FunctionKey:    zapcore.OmitKey,
145		MessageKey:     "M",
146		StacktraceKey:  "S",
147		LineEnding:     zapcore.DefaultLineEnding,
148		EncodeLevel:    zapcore.CapitalLevelEncoder,
149		EncodeTime:     zapcore.ISO8601TimeEncoder,
150		EncodeDuration: zapcore.StringDurationEncoder,
151		EncodeCaller:   zapcore.ShortCallerEncoder,
152	}
153}
154
155// NewDevelopmentConfig is a reasonable development logging configuration.
156// Logging is enabled at DebugLevel and above.
157//
158// It enables development mode (which makes DPanicLevel logs panic), uses a
159// console encoder, writes to standard error, and disables sampling.
160// Stacktraces are automatically included on logs of WarnLevel and above.
161func NewDevelopmentConfig() Config {
162	return Config{
163		Level:            NewAtomicLevelAt(DebugLevel),
164		Development:      true,
165		Encoding:         "console",
166		EncoderConfig:    NewDevelopmentEncoderConfig(),
167		OutputPaths:      []string{"stderr"},
168		ErrorOutputPaths: []string{"stderr"},
169	}
170}
171
172// Build constructs a logger from the Config and Options.
173func (cfg Config) Build(opts ...Option) (*Logger, error) {
174	enc, err := cfg.buildEncoder()
175	if err != nil {
176		return nil, err
177	}
178
179	sink, errSink, err := cfg.openSinks()
180	if err != nil {
181		return nil, err
182	}
183
184	if cfg.Level == (AtomicLevel{}) {
185		return nil, fmt.Errorf("missing Level")
186	}
187
188	log := New(
189		zapcore.NewCore(enc, sink, cfg.Level),
190		cfg.buildOptions(errSink)...,
191	)
192	if len(opts) > 0 {
193		log = log.WithOptions(opts...)
194	}
195	return log, nil
196}
197
198func (cfg Config) buildOptions(errSink zapcore.WriteSyncer) []Option {
199	opts := []Option{ErrorOutput(errSink)}
200
201	if cfg.Development {
202		opts = append(opts, Development())
203	}
204
205	if !cfg.DisableCaller {
206		opts = append(opts, AddCaller())
207	}
208
209	stackLevel := ErrorLevel
210	if cfg.Development {
211		stackLevel = WarnLevel
212	}
213	if !cfg.DisableStacktrace {
214		opts = append(opts, AddStacktrace(stackLevel))
215	}
216
217	if scfg := cfg.Sampling; scfg != nil {
218		opts = append(opts, WrapCore(func(core zapcore.Core) zapcore.Core {
219			var samplerOpts []zapcore.SamplerOption
220			if scfg.Hook != nil {
221				samplerOpts = append(samplerOpts, zapcore.SamplerHook(scfg.Hook))
222			}
223			return zapcore.NewSamplerWithOptions(
224				core,
225				time.Second,
226				cfg.Sampling.Initial,
227				cfg.Sampling.Thereafter,
228				samplerOpts...,
229			)
230		}))
231	}
232
233	if len(cfg.InitialFields) > 0 {
234		fs := make([]Field, 0, len(cfg.InitialFields))
235		keys := make([]string, 0, len(cfg.InitialFields))
236		for k := range cfg.InitialFields {
237			keys = append(keys, k)
238		}
239		sort.Strings(keys)
240		for _, k := range keys {
241			fs = append(fs, Any(k, cfg.InitialFields[k]))
242		}
243		opts = append(opts, Fields(fs...))
244	}
245
246	return opts
247}
248
249func (cfg Config) openSinks() (zapcore.WriteSyncer, zapcore.WriteSyncer, error) {
250	sink, closeOut, err := Open(cfg.OutputPaths...)
251	if err != nil {
252		return nil, nil, err
253	}
254	errSink, _, err := Open(cfg.ErrorOutputPaths...)
255	if err != nil {
256		closeOut()
257		return nil, nil, err
258	}
259	return sink, errSink, nil
260}
261
262func (cfg Config) buildEncoder() (zapcore.Encoder, error) {
263	return newEncoder(cfg.Encoding, cfg.EncoderConfig)
264}
265