diff options
Diffstat (limited to 'vendor/go.uber.org/zap/README.md')
| -rw-r--r-- | vendor/go.uber.org/zap/README.md | 136 |
1 files changed, 136 insertions, 0 deletions
diff --git a/vendor/go.uber.org/zap/README.md b/vendor/go.uber.org/zap/README.md new file mode 100644 index 00000000..f4fd1cb4 --- /dev/null +++ b/vendor/go.uber.org/zap/README.md @@ -0,0 +1,136 @@ +# :zap: zap [![GoDoc][doc-img]][doc] [![Build Status][ci-img]][ci] [![Coverage Status][cov-img]][cov] + +Blazing fast, structured, leveled logging in Go. + +## Installation + +`go get -u go.uber.org/zap` + +Note that zap only supports the two most recent minor versions of Go. + +## Quick Start + +In contexts where performance is nice, but not critical, use the +`SugaredLogger`. It's 4-10x faster than other structured logging +packages and includes both structured and `printf`-style APIs. + +```go +logger, _ := zap.NewProduction() +defer logger.Sync() // flushes buffer, if any +sugar := logger.Sugar() +sugar.Infow("failed to fetch URL", + // Structured context as loosely typed key-value pairs. + "url", url, + "attempt", 3, + "backoff", time.Second, +) +sugar.Infof("Failed to fetch URL: %s", url) +``` + +When performance and type safety are critical, use the `Logger`. It's even +faster than the `SugaredLogger` and allocates far less, but it only supports +structured logging. + +```go +logger, _ := zap.NewProduction() +defer logger.Sync() +logger.Info("failed to fetch URL", + // Structured context as strongly typed Field values. + zap.String("url", url), + zap.Int("attempt", 3), + zap.Duration("backoff", time.Second), +) +``` + +See the [documentation][doc] and [FAQ](FAQ.md) for more details. + +## Performance + +For applications that log in the hot path, reflection-based serialization and +string formatting are prohibitively expensive — they're CPU-intensive +and make many small allocations. Put differently, using `encoding/json` and +`fmt.Fprintf` to log tons of `interface{}`s makes your application slow. + +Zap takes a different approach. It includes a reflection-free, zero-allocation +JSON encoder, and the base `Logger` strives to avoid serialization overhead +and allocations wherever possible. By building the high-level `SugaredLogger` +on that foundation, zap lets users *choose* when they need to count every +allocation and when they'd prefer a more familiar, loosely typed API. + +As measured by its own [benchmarking suite][], not only is zap more performant +than comparable structured logging packages — it's also faster than the +standard library. Like all benchmarks, take these with a grain of salt.<sup +id="anchor-versions">[1](#footnote-versions)</sup> + +Log a message and 10 fields: + +| Package | Time | Objects Allocated | +| :--- | :---: | :---: | +| :zap: zap | 3131 ns/op | 5 allocs/op | +| :zap: zap (sugared) | 4173 ns/op | 21 allocs/op | +| zerolog | 16154 ns/op | 90 allocs/op | +| lion | 16341 ns/op | 111 allocs/op | +| go-kit | 17049 ns/op | 126 allocs/op | +| logrus | 23662 ns/op | 142 allocs/op | +| log15 | 36351 ns/op | 149 allocs/op | +| apex/log | 42530 ns/op | 126 allocs/op | + +Log a message with a logger that already has 10 fields of context: + +| Package | Time | Objects Allocated | +| :--- | :---: | :---: | +| :zap: zap | 380 ns/op | 0 allocs/op | +| :zap: zap (sugared) | 564 ns/op | 2 allocs/op | +| zerolog | 321 ns/op | 0 allocs/op | +| lion | 7092 ns/op | 39 allocs/op | +| go-kit | 20226 ns/op | 115 allocs/op | +| logrus | 22312 ns/op | 130 allocs/op | +| log15 | 28788 ns/op | 79 allocs/op | +| apex/log | 42063 ns/op | 115 allocs/op | + +Log a static string, without any context or `printf`-style templating: + +| Package | Time | Objects Allocated | +| :--- | :---: | :---: | +| :zap: zap | 361 ns/op | 0 allocs/op | +| :zap: zap (sugared) | 534 ns/op | 2 allocs/op | +| zerolog | 323 ns/op | 0 allocs/op | +| standard library | 575 ns/op | 2 allocs/op | +| go-kit | 922 ns/op | 13 allocs/op | +| lion | 1413 ns/op | 10 allocs/op | +| logrus | 2291 ns/op | 27 allocs/op | +| apex/log | 3690 ns/op | 11 allocs/op | +| log15 | 5954 ns/op | 26 allocs/op | + +## Development Status: Stable + +All APIs are finalized, and no breaking changes will be made in the 1.x series +of releases. Users of semver-aware dependency management systems should pin +zap to `^1`. + +## Contributing + +We encourage and support an active, healthy community of contributors — +including you! Details are in the [contribution guide](CONTRIBUTING.md) and +the [code of conduct](CODE_OF_CONDUCT.md). The zap maintainers keep an eye on +issues and pull requests, but you can also report any negative conduct to +oss-conduct@uber.com. That email list is a private, safe space; even the zap +maintainers don't have access, so don't hesitate to hold us to a high +standard. + +<hr> + +Released under the [MIT License](LICENSE.txt). + +<sup id="footnote-versions">1</sup> In particular, keep in mind that we may be +benchmarking against slightly older versions of other packages. Versions are +pinned in zap's [glide.lock][] file. [↩](#anchor-versions) + +[doc-img]: https://godoc.org/go.uber.org/zap?status.svg +[doc]: https://godoc.org/go.uber.org/zap +[ci-img]: https://travis-ci.org/uber-go/zap.svg?branch=master +[ci]: https://travis-ci.org/uber-go/zap +[cov-img]: https://codecov.io/gh/uber-go/zap/branch/master/graph/badge.svg +[cov]: https://codecov.io/gh/uber-go/zap +[benchmarking suite]: https://github.com/uber-go/zap/tree/master/benchmarks +[glide.lock]: https://github.com/uber-go/zap/blob/master/glide.lock |