114 lines
5.1 KiB
Go
114 lines
5.1 KiB
Go
// Copyright (c) 2016 Uber Technologies, Inc.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a copy
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// of this software and associated documentation files (the "Software"), to deal
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// in the Software without restriction, including without limitation the rights
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// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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// copies of the Software, and to permit persons to whom the Software is
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// furnished to do so, subject to the following conditions:
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//
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// The above copyright notice and this permission notice shall be included in
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// all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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// THE SOFTWARE.
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// Package zap provides fast, structured, leveled logging.
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//
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// For applications that log in the hot path, reflection-based serialization
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// and string formatting are prohibitively expensive - they're CPU-intensive
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// and make many small allocations. Put differently, using json.Marshal and
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// fmt.Fprintf to log tons of interface{} makes your application slow.
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//
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// Zap takes a different approach. It includes a reflection-free,
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// zero-allocation JSON encoder, and the base Logger strives to avoid
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// serialization overhead and allocations wherever possible. By building the
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// high-level SugaredLogger on that foundation, zap lets users choose when
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// they need to count every allocation and when they'd prefer a more familiar,
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// loosely typed API.
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//
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// Choosing a Logger
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//
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// In contexts where performance is nice, but not critical, use the
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// SugaredLogger. It's 4-10x faster than other structured logging packages and
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// supports both structured and printf-style logging. Like log15 and go-kit,
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// the SugaredLogger's structured logging APIs are loosely typed and accept a
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// variadic number of key-value pairs. (For more advanced use cases, they also
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// accept strongly typed fields - see the SugaredLogger.With documentation for
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// details.)
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// sugar := zap.NewExample().Sugar()
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// defer sugar.Sync()
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// sugar.Infow("failed to fetch URL",
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// "url", "http://example.com",
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// "attempt", 3,
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// "backoff", time.Second,
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// )
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// sugar.Infof("failed to fetch URL: %s", "http://example.com")
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//
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// By default, loggers are unbuffered. However, since zap's low-level APIs
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// allow buffering, calling Sync before letting your process exit is a good
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// habit.
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//
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// In the rare contexts where every microsecond and every allocation matter,
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// use the Logger. It's even faster than the SugaredLogger and allocates far
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// less, but it only supports strongly-typed, structured logging.
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// logger := zap.NewExample()
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// defer logger.Sync()
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// logger.Info("failed to fetch URL",
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// zap.String("url", "http://example.com"),
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// zap.Int("attempt", 3),
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// zap.Duration("backoff", time.Second),
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// )
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//
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// Choosing between the Logger and SugaredLogger doesn't need to be an
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// application-wide decision: converting between the two is simple and
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// inexpensive.
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// logger := zap.NewExample()
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// defer logger.Sync()
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// sugar := logger.Sugar()
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// plain := sugar.Desugar()
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//
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// Configuring Zap
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//
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// The simplest way to build a Logger is to use zap's opinionated presets:
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// NewExample, NewProduction, and NewDevelopment. These presets build a logger
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// with a single function call:
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// logger, err := zap.NewProduction()
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// if err != nil {
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// log.Fatalf("can't initialize zap logger: %v", err)
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// }
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// defer logger.Sync()
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//
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// Presets are fine for small projects, but larger projects and organizations
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// naturally require a bit more customization. For most users, zap's Config
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// struct strikes the right balance between flexibility and convenience. See
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// the package-level BasicConfiguration example for sample code.
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//
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// More unusual configurations (splitting output between files, sending logs
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// to a message queue, etc.) are possible, but require direct use of
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// go.uber.org/zap/zapcore. See the package-level AdvancedConfiguration
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// example for sample code.
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//
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// Extending Zap
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//
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// The zap package itself is a relatively thin wrapper around the interfaces
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// in go.uber.org/zap/zapcore. Extending zap to support a new encoding (e.g.,
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// BSON), a new log sink (e.g., Kafka), or something more exotic (perhaps an
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// exception aggregation service, like Sentry or Rollbar) typically requires
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// implementing the zapcore.Encoder, zapcore.WriteSyncer, or zapcore.Core
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// interfaces. See the zapcore documentation for details.
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//
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// Similarly, package authors can use the high-performance Encoder and Core
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// implementations in the zapcore package to build their own loggers.
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//
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// Frequently Asked Questions
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//
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// An FAQ covering everything from installation errors to design decisions is
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// available at https://github.com/uber-go/zap/blob/master/FAQ.md.
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package zap // import "go.uber.org/zap"
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