A simple go logger for easy logging in your programs. Allows setting custom format for messages.
go get github.com/apsdehal/go-logger
Use go get -u to update the package.
Example program demonstrates how to use the logger. See below for formatting instructions.
package main
import (
"github.com/apsdehal/go-logger""os"
)
funcmain () {
// Get the instance for logger class, "test" is the module name, 1 is used to// state if we want coloring// Third option is optional and is instance of type io.Writer, defaults to os.Stderrlog, err:=logger.New("test", 1, os.Stdout)
iferr!=nil {
panic(err) // Check for error
}
// Critically log criticallog.Critical("This is Critical!")
log.CriticalF("%+v", err)
// You can also use fmt compliant naming scheme such as log.Criticalf, log.Panicf etc// with small 'f'// Debug// Since default logging level is Info this won't print anythinglog.Debug("This is Debug!")
log.DebugF("Here are some numbers: %d %d %f", 10, -3, 3.14)
// Give the Warninglog.Warning("This is Warning!")
log.WarningF("This is Warning!")
// Show the errorlog.Error("This is Error!")
log.ErrorF("This is Error!")
// Noticelog.Notice("This is Notice!")
log.NoticeF("%s %s", "This", "is Notice!")
// Show the infolog.Info("This is Info!")
log.InfoF("This is %s!", "Info")
log.StackAsError("Message before printing stack");
// Show warning with formatlog.SetFormat("[%{module}] [%{level}] %{message}")
log.Warning("This is Warning!") // output: "[test] [WARNING] This is Warning!"// Also you can set your format as default format for all new loggerslogger.SetDefaultFormat("%{message}")
log2, _:=logger.New("pkg", 1, os.Stdout)
log2.Error("This is Error!") // output: "This is Error!"// Use log levels to set your log prioritylog2.SetLogLevel(DebugLevel)
// This will be printedlog2.Debug("This is debug!")
log2.SetLogLevel(WarningLevel)
// This won't be printedlog2.Info("This is an error!")
}By default all log messages have format that you can see above (on pic). But you can override the default format and set format that you want.
You can do it for Logger instance (after creating logger) ...
log, _:=logger.New("pkgname", 1)
log.SetFormat(format)... or for package
logger.SetDefaultFormat(format)If you do it for package, all existing loggers will print log messages with format that these used already. But all newest loggers (which will be created after changing format for package) will use your specified format.
But anyway after this, you can still set format of message for specific Logger instance.
Format of log message must contains verbs that represent some info about current log entry. Ofc, format can contain not only verbs but also something else (for example text, digits, symbols, etc)
You can use the following verbs:
%{id} - means number of current log message
%{module} - means module name (that you passed to func New())
%{time} - means current time in format "2006-01-02 15:04:05"
%{time:format} - means current time in format that you want
(supports all formats supported by go package "time")
%{level} - means level name (upper case) of log message ("ERROR", "DEBUG", etc)
%{lvl} - means first 3 letters of level name (upper case) of log message ("ERR", "DEB", etc)
%{file} - means name of file in what you wanna write log
%{filename} - means the same as %{file}
%{line} - means line number of file in what you wanna write log
%{message} - means your log message
Non-existent verbs (like %{nonex-verb} or %{}) will be replaced by an empty string.
Invalid verbs (like %{inv-verb) will be treated as plain text.
Run:
go test loggerto run test on logger.go test -bench=.for benchmarks.
Thanks goes to all go-loggers out there which I used as reference.
Following contributors have made major contributions to go-logger:
The BSD 3-Clause license, the same as the Go language.