mirror of https://github.com/status-im/op-geth.git
78 lines
3.2 KiB
Markdown
78 lines
3.2 KiB
Markdown
|
|
|
|
# log15 [](https://godoc.org/github.com/inconshreveable/log15) [](https://travis-ci.org/inconshreveable/log15)
|
|
|
|
Package log15 provides an opinionated, simple toolkit for best-practice logging in Go (golang) that is both human and machine readable. It is modeled after the Go standard library's [`io`](https://golang.org/pkg/io/) and [`net/http`](https://golang.org/pkg/net/http/) packages and is an alternative to the standard library's [`log`](https://golang.org/pkg/log/) package.
|
|
|
|
## Features
|
|
- A simple, easy-to-understand API
|
|
- Promotes structured logging by encouraging use of key/value pairs
|
|
- Child loggers which inherit and add their own private context
|
|
- Lazy evaluation of expensive operations
|
|
- Simple Handler interface allowing for construction of flexible, custom logging configurations with a tiny API.
|
|
- Color terminal support
|
|
- Built-in support for logging to files, streams, syslog, and the network
|
|
- Support for forking records to multiple handlers, buffering records for output, failing over from failed handler writes, + more
|
|
|
|
## Versioning
|
|
The API of the master branch of log15 should always be considered unstable. If you want to rely on a stable API,
|
|
you must vendor the library.
|
|
|
|
## Importing
|
|
|
|
```go
|
|
import log "github.com/inconshreveable/log15"
|
|
```
|
|
|
|
## Examples
|
|
|
|
```go
|
|
// all loggers can have key/value context
|
|
srvlog := log.New("module", "app/server")
|
|
|
|
// all log messages can have key/value context
|
|
srvlog.Warn("abnormal conn rate", "rate", curRate, "low", lowRate, "high", highRate)
|
|
|
|
// child loggers with inherited context
|
|
connlog := srvlog.New("raddr", c.RemoteAddr())
|
|
connlog.Info("connection open")
|
|
|
|
// lazy evaluation
|
|
connlog.Debug("ping remote", "latency", log.Lazy{pingRemote})
|
|
|
|
// flexible configuration
|
|
srvlog.SetHandler(log.MultiHandler(
|
|
log.StreamHandler(os.Stderr, log.LogfmtFormat()),
|
|
log.LvlFilterHandler(
|
|
log.LvlError,
|
|
log.Must.FileHandler("errors.json", log.JSONFormat()))))
|
|
```
|
|
|
|
Will result in output that looks like this:
|
|
|
|
```
|
|
WARN[06-17|21:58:10] abnormal conn rate module=app/server rate=0.500 low=0.100 high=0.800
|
|
INFO[06-17|21:58:10] connection open module=app/server raddr=10.0.0.1
|
|
```
|
|
|
|
## Breaking API Changes
|
|
The following commits broke API stability. This reference is intended to help you understand the consequences of updating to a newer version
|
|
of log15.
|
|
|
|
- 57a084d014d4150152b19e4e531399a7145d1540 - Added a `Get()` method to the `Logger` interface to retrieve the current handler
|
|
- 93404652ee366648fa622b64d1e2b67d75a3094a - `Record` field `Call` changed to `stack.Call` with switch to `github.com/go-stack/stack`
|
|
- a5e7613673c73281f58e15a87d2cf0cf111e8152 - Restored `syslog.Priority` argument to the `SyslogXxx` handler constructors
|
|
|
|
## FAQ
|
|
|
|
### The varargs style is brittle and error prone! Can I have type safety please?
|
|
Yes. Use `log.Ctx`:
|
|
|
|
```go
|
|
srvlog := log.New(log.Ctx{"module": "app/server"})
|
|
srvlog.Warn("abnormal conn rate", log.Ctx{"rate": curRate, "low": lowRate, "high": highRate})
|
|
```
|
|
|
|
## License
|
|
Apache
|