github.com/mrfranklin/go-log

This project is fork from inconshreveable/log15. And provides some new features:

• display time in the format of milliseconds for default
• support trace log level
• using package name with log instead of log15
• program exit when call log.Crit()
• support to print the file path and the number of line where the log is located, using log.EnablePrintFilePath()

Usage:

• print a trace level log

import "github.com/mrFranklin/go-log"

log.Trace("this is a pretty log", "key", "hello world")

output:

TRACE[01-11|19:35:53.097] this is a pretty log                     key="hello world"

• print the file path and the number of line:

func init() {
	log.EnablePrintFilePath("github.com/mrFranklin/go-log")
}

func main() {
    log.Info("this is a pretty log", "key", "hello world")
}

output:

INFO[01-22|16:14:42.847][samples/main.go:23] this is a pretty log               key="hello world"

---

log15

package log 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 and net/http packages and is an alternative to the standard library's 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

import log "github.com/inconshreveable/log15"

Examples

// 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:

srvlog := log.New(log.Ctx{"module": "app/server"})
srvlog.Warn("abnormal conn rate", log.Ctx{"rate": curRate, "low": lowRate, "high": highRate})

Regenerating the CONTRIBUTORS file

go get -u github.com/kevinburke/write_mailmap
write_mailmap > CONTRIBUTORS

License

Apache