SIMPLEXLOG leveled logging library

Simplexlog simple wrapper for the go standard log package, that adds logging levels.

The standard log package is enough (IMHO) for many applications, but sometimes is usefull to have some logging levels. Simplexlog adds some logging levels and the ability to use different io.Writer for different level. All the standard logging flags can be used.

The logging levels are: TRACE, DEBUG, CRITICAL, ERROR, WARNING, NOTICE, INFO or ALL. Functions like Panic or Fatal are also available, their massage are redirect to CRITICAL.

Since simplexlog write to an io.Writer, you can provvide, for e.g, your custom io.Writer for writting name of function. Take a look at the examples.

Simplexlog is concurrent safe.

Installation

The package is go gettable: go get -u github.com/vpxyz/simplexlog

Example

basic usage:

package main
import (
"github.com/vpxyz/simplexlog"
)
funcmain() {
// by default use os.Stderr for error, critical, fatal and panic, and os.Stdout for othersl:=simplexlog.New()
fmt.Printf("available levels: %s\n", l.LevelNames())
// the defaul log level is Infol.Trace("Trace log")
l.Info("Info log")
l.Notice("Notice log")
l.Warning("Warning log")
l.Debug("Debug log")
l.Error("Error log")
l.Critical("Critical log")
l.SwitchTo(sl.Warning)
l.Info("This is hidden")
// if you need, you can pass around an standard log.Logger, bypassing the LogLevel settingl.CriticalLogger().Print("test")
}

custom io.Writer, this approach can be useful even with the standard log package:

package main
import (
"fmt""path/filepath""runtime""strings"
sl "github.com/vpxyz/simplexlog"
)
var (
logger*sl.Logger
)
typeLogWriterstruct{}
func (fLogWriter) Write(p []byte) (nint, errerror) {
pc, file, line, ok:=runtime.Caller(4)
if!ok {
file="?"line=0
}
fn:=runtime.FuncForPC(pc)
fmt.Printf("%s: %s, line %d, %s\n", strings.ReplaceAll(string(p), "\n", ""), filepath.Base(file), line, fn.Name())
returnlen(p), nil
}
funcdumb() {
logger.Debug("who I am ?")
}
funcmain() {
// write func name for debuggingdebugLw:=LogWriter{}
logger=sl.New(sl.SetDebug(sl.Config{Out: debugLw, Label: fmt.Sprintf("%-9s", sl.LevelDebug), Flags: sl.DefaultLogFlags}))
// logger = sl.New()logger.SwitchTo(sl.Debug)
dumb()
}

weird example:

package main
import (
sl "github.com/vpxyz/simplexlog""log""os""bytes"
)
funcmain() {
// Set different tag for any level// If you need, you can use a different io.Writer for each level witch different flags and prefix// If you want color labels, simply put colors escape sequence around label. For e.g. "\x1b[20;32m"+sl.LevelInfo+"\x1b[0m"l:=sl.New(
sl.SetDebug(sl.Config{Out: os.Stdout, Label: sl.LevelInfo+" ==> ", Flags: sl.DefaultLogFlags|log.Lshortfile}),
sl.SetTrace(sl.Config{Out: os.Stdout, Label: sl.LevelTrace+" ==> ", Flags: sl.DefaultLogFlags|log.Lshortfile}),
sl.SetInfo(sl.Config{Out: os.Stdout, Label: sl.LevelInfo+" =>", Flags: sl.DefaultLogFlags}),
sl.SetNotice(sl.Config{Out: os.Stdout, Label: fmt.Sprintf("%-10s", "["+sl.LevelNotice+"]:"), Flags: sl.DefaultLogFlags}),
sl.SetWarning(sl.Config{Out: os.Stdout, Label: " 😒 ", Flags: sl.DefaultLogFlags}),
sl.SetError(sl.Config{Out: os.Stderr, Label: " 🥲 "+" ", Flags: sl.DefaultLogFlags}),
sl.SetCritical(sl.Config{Out: os.Stderr, Label: " 😡 ", Flags: sl.DefaultLogFlags|log.Lshortfile}),
)
// enable all log levell.SwitchTo(sl.All)
l.Tracef("Trace log %s", "!!!")
l.Info("Info log")
l.Notice("Notice log")
l.Warning("Warning log")
l.Debug("Debug log")
l.Error("Error log")
l.Critical("Critical log")
// switch log levell.SwitchTo(sl.Warning)
l.Info("This is hidden")
// if you need, you can pass around an standard log.Logger, bypassing the LogLevel settingl.CriticalLogger().Print("test")
// switch logging level using logging level name (case insensitive)l.SwitchTo("error")
l.Infof("Info log %s", "🦇")
l.Noticef("Notice log")
l.Warningf("Warning log")
l.Debugf("Debug log")
l.Errorf("Error log")
l.Criticalf("Critical log")
// change the output of the Info levelvarbuf bytes.Bufferl.SetOutput(sl.Info, &buf)
// change label of Error levell.SetLabel(sl.Error, " 🐛 ")
// change flags of Info levell.SetFlags(sl.Info, sl.DefaultLogFlags|log.Lshortfile)
}