log

Overview ¶

Package log contains NullLogger, StdLogger and the Logger interface.

Logging ¶

Interface Logger is used all over the place and there are no other dependencies. Default Logger is a null logger. You must take care to implement a logger which is also thread safe.

Convention: Because recording a human-meaningful message is common and good practice, the first argument to every logging method is the value to the *implicit* key 'msg'. You may supply any additional context as a set of key/value pairs to the logging function.

To initialize your own logger you must somewhere set the logging object to the util/log package.

import "github.com/corestoreio/csfw/utils/log"

func init() {
	log.Set(NewMyCustomLogger())
}

Level guards exists to avoid the cost of building arguments. Get in the habit of using guards.

import "github.com/corestoreio/csfw/utils/log"

if log.IsDebug() {
	log.Debug("some message", "key1", expensive())
}

Standardizes on key-value pair argument sequence:

import "github.com/corestoreio/csfw/utils/log"

log.Debug("message from inside Fn()", "key1", value1, "key2", value2)

// instead of this
log.WithFields(logrus.Fields{"m": "pkg", "key1": value1, "key2": value2}).Debug("inside fn()")

Please consider the key-value pairs when implementing your own logger.

Recommended Loggers are https://github.com/mgutz/logxi and https://github.com/Sirupsen/logrus and https://github.com/inconshreveable/log15

Standard Logger ¶

CoreStore provides a leveled logger based on Go's standard library without any dependencies. This StdLogger obeys to the interface Logger of this package.

import "github.com/corestoreio/csfw/utils/log"

func init() {
	log.Set(log.NewStdLogger())
}

log.NewStdLogger() accepts a wide range of optional arguments. Please see the functions Std*Option().