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"
)
func main () {
// 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.Stderr
log, err := logger.New("test", 1, os.Stdout)
if err != nil {
panic(err) // Check for error
}
// Critically log critical
log.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 anything
log.Debug("This is Debug!")
log.DebugF("Here are some numbers: %d %d %f", 10, -3, 3.14)
// Give the Warning
log.Warning("This is Warning!")
log.WarningF("This is Warning!")
// Show the error
log.Error("This is Error!")
log.ErrorF("This is Error!")
// Notice
log.Notice("This is Notice!")
log.NoticeF("%s %s", "This", "is Notice!")
// Show the info
log.Info("This is Info!")
log.InfoF("This is %s!", "Info")
log.StackAsError("Message before printing stack");
// Show warning with format
log.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 loggers
logger.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 priority
log2.SetLogLevel(DebugLevel)
// This will be printed
log2.Debug("This is debug!")
log2.SetLogLevel(WarningLevel)
// This won't be printed
log2.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.