xlog

package main

import (
	"io"
	"os"

	"github.com/actforgood/xlog"
)

func main() {
	// In this example we create a (async)logger that writes
	// logs to standard output.

	opts := xlog.NewCommonOpts()
	opts.MinLevel = xlog.FixedLevelProvider(xlog.LevelNone)
	opts.AdditionalKeyValues = []any{
		"appName", "demo",
		"env", "dev",
	}
	opts.Time = func() any { // mock time for output check
		return "2022-03-16T16:01:20Z"
	}
	opts.Source = xlog.SourceProvider(4, 1) // keep only filename for output check

	logger := xlog.NewAsyncLogger(
		os.Stdout,
		xlog.AsyncLoggerWithOptions(opts),
		xlog.AsyncLoggerWithWorkersNo(2), // since workers no > 1, we expect output to be unordered.
	)
	defer logger.Close()

	logger.Log(xlog.MessageKey, "Hello World", "year", 2022)
	logger.Debug(xlog.MessageKey, "Hello World", "year", 2022)
	logger.Info(xlog.MessageKey, "Hello World", "year", 2022)
	logger.Warn(xlog.MessageKey, "Hello World", "year", 2022)
	logger.Error(xlog.MessageKey, "Could not read file", xlog.ErrorKey, io.ErrUnexpectedEOF, "file", "/some/file")
	logger.Critical(xlog.MessageKey, "DB connection is down")

}

Output:

{"appName":"demo","date":"2022-03-16T16:01:20Z","env":"dev","msg":"Hello World","src":"/logger_async_test.go:43","year":2022}
{"appName":"demo","date":"2022-03-16T16:01:20Z","env":"dev","lvl":"DEBUG","msg":"Hello World","src":"/logger_async_test.go:44","year":2022}
{"appName":"demo","date":"2022-03-16T16:01:20Z","env":"dev","lvl":"INFO","msg":"Hello World","src":"/logger_async_test.go:45","year":2022}
{"appName":"demo","date":"2022-03-16T16:01:20Z","env":"dev","lvl":"WARN","msg":"Hello World","src":"/logger_async_test.go:46","year":2022}
{"appName":"demo","date":"2022-03-16T16:01:20Z","env":"dev","err":"unexpected EOF","file":"/some/file","lvl":"ERROR","msg":"Could not read file","src":"/logger_async_test.go:47"}
{"appName":"demo","date":"2022-03-16T16:01:20Z","env":"dev","lvl":"CRITICAL","msg":"DB connection is down","src":"/logger_async_test.go:48"}

package main

import (
	"os"

	"github.com/actforgood/xlog"
)

func main() {
	// In this example we create a (multi)logger that writes
	// logs to standard output, and to a file.

	stdOutLgrOpts := xlog.NewCommonOpts()
	stdOutLgrOpts.MinLevel = xlog.FixedLevelProvider(xlog.LevelNone)
	stdOutLgrOpts.Time = func() any { // mock time for output check
		return "2022-03-15T16:01:20Z"
	}
	stdOutLgrOpts.Source = xlog.SourceProvider(5, 1) // keep only filename for output check
	stdOutLgr := xlog.NewSyncLogger(
		os.Stdout,
		xlog.SyncLoggerWithOptions(stdOutLgrOpts),
	)

	fileLgrOpts := xlog.NewCommonOpts()
	fileLgrOpts.MinLevel = xlog.FixedLevelProvider(xlog.LevelNone)
	fileLgrOpts.Time = func() any { // mock time for output check
		return "2022-03-15T16:01:20Z"
	}
	fileLgrOpts.Source = xlog.SourceProvider(5, 1) // keep only filename for output check
	f, err := os.CreateTemp("", "x.log-*")         // you will have your well known path defined
	if err != nil {
		panic(err)
	}
	fileLgr := xlog.NewSyncLogger(
		f,
		xlog.SyncLoggerWithOptions(fileLgrOpts),
	)

	logger := xlog.NewMultiLogger(stdOutLgr, fileLgr)
	defer func() {
		_ = logger.Close()
		_ = f.Close()
		_ = os.Remove(f.Name()) // you won't remove the file
	}()

	logger.Debug("msg", "I get written to standard output and to a file")

}

Output:

{"date":"2022-03-15T16:01:20Z","lvl":"DEBUG","msg":"I get written to standard output and to a file","src":"/logger_multi_test.go:91"}

package main

import (
	"os"

	"github.com/actforgood/xlog"
)

func main() {
	// In this example we create a (multi)logger that writes
	// debug and info logs to standard output and
	// warning, error and critical logs to error output.

	errLgrOpts := xlog.NewCommonOpts()
	errLgrOpts.MinLevel = xlog.FixedLevelProvider(xlog.LevelWarning)
	errLgrOpts.Time = func() any { // mock time for output check
		return "2022-03-20T16:01:20Z"
	}
	errLgrOpts.Source = xlog.SourceProvider(5, 1) // keep only filename for output check
	errLgr := xlog.NewSyncLogger(
		os.Stderr,
		xlog.SyncLoggerWithOptions(errLgrOpts),
	)

	dbgLgrOpts := xlog.NewCommonOpts()
	dbgLgrOpts.MinLevel = xlog.FixedLevelProvider(xlog.LevelDebug)
	dbgLgrOpts.MaxLevel = xlog.FixedLevelProvider(xlog.LevelInfo)
	dbgLgrOpts.Time = func() any { // mock time for output check
		return "2022-03-20T16:01:20Z"
	}
	dbgLgrOpts.Source = xlog.SourceProvider(5, 1) // keep only filename for output check
	dbgLgr := xlog.NewSyncLogger(
		os.Stdout,
		xlog.SyncLoggerWithOptions(dbgLgrOpts),
	)

	logger := xlog.NewMultiLogger(errLgr, dbgLgr)
	defer logger.Close()

	logger.Debug("msg", "I get written to standard output")
	logger.Error("msg", "I get written to standard error")

}

Output:

{"date":"2022-03-20T16:01:20Z","lvl":"DEBUG","msg":"I get written to standard output","src":"/logger_multi_test.go:47"}

package main

import (
	"io"
	"os"

	"github.com/actforgood/xlog"
)

func main() {
	// In this example we create a (sync)logger that writes
	// logs to standard output.

	opts := xlog.NewCommonOpts()
	opts.MinLevel = xlog.FixedLevelProvider(xlog.LevelNone)
	opts.AdditionalKeyValues = []any{
		"appName", "demo",
		"env", "dev",
	}
	opts.Time = func() any { // mock time for output check
		return "2022-03-14T16:01:20Z"
	}
	opts.Source = xlog.SourceProvider(4, 1) // keep only filename for output check

	logger := xlog.NewSyncLogger(
		os.Stdout,
		xlog.SyncLoggerWithOptions(opts),
	)
	defer logger.Close()

	logger.Log(xlog.MessageKey, "Hello World", "year", 2022)
	logger.Debug(xlog.MessageKey, "Hello World", "year", 2022)
	logger.Info(xlog.MessageKey, "Hello World", "year", 2022)
	logger.Warn(xlog.MessageKey, "Hello World", "year", 2022)
	logger.Error(xlog.MessageKey, "Could not read file", xlog.ErrorKey, io.ErrUnexpectedEOF, "file", "/some/file")
	logger.Critical(xlog.MessageKey, "DB connection is down")

}

Output:

{"appName":"demo","date":"2022-03-14T16:01:20Z","env":"dev","msg":"Hello World","src":"/logger_sync_test.go:42","year":2022}
{"appName":"demo","date":"2022-03-14T16:01:20Z","env":"dev","lvl":"DEBUG","msg":"Hello World","src":"/logger_sync_test.go:43","year":2022}
{"appName":"demo","date":"2022-03-14T16:01:20Z","env":"dev","lvl":"INFO","msg":"Hello World","src":"/logger_sync_test.go:44","year":2022}
{"appName":"demo","date":"2022-03-14T16:01:20Z","env":"dev","lvl":"WARN","msg":"Hello World","src":"/logger_sync_test.go:45","year":2022}
{"appName":"demo","date":"2022-03-14T16:01:20Z","env":"dev","err":"unexpected EOF","file":"/some/file","lvl":"ERROR","msg":"Could not read file","src":"/logger_sync_test.go:46"}
{"appName":"demo","date":"2022-03-14T16:01:20Z","env":"dev","lvl":"CRITICAL","msg":"DB connection is down","src":"/logger_sync_test.go:47"}

package main

import (
	"os"

	"github.com/actforgood/xlog"
)

func main() {
	// In this example we create a "dev", colorized levels, logger based on TextFormatter.

	opts := xlog.NewCommonOpts()
	opts.MinLevel = xlog.FixedLevelProvider(xlog.LevelNone)
	opts.Time = func() any { // mock time for output check
		return "2022-03-14T16:01:20Z"
	}
	opts.Source = xlog.SourceProvider(4, 1)   // keep only filename for output check
	opts.LevelLabels = map[xlog.Level]string{ // we nicely colorize the levels
		xlog.LevelDebug:    "\033[0;34mDEBUG\033[0m",    // blue
		xlog.LevelInfo:     "\033[0;36mINFO\033[0m",     // cyan
		xlog.LevelWarning:  "\033[0;33mWARN\033[0m",     // yellow
		xlog.LevelError:    "\033[0;31mERROR\033[0m",    // red
		xlog.LevelCritical: "\033[0;31mCRITICAL\033[0m", // red
	}
	logger := xlog.NewSyncLogger(
		os.Stdout,
		xlog.SyncLoggerWithOptions(opts),
		xlog.SyncLoggerWithFormatter(xlog.TextFormatter(opts)),
	)
	defer logger.Close()

	logger.Debug(xlog.MessageKey, "Hello World", "year", 2022)

}

Output:

2022-03-14T16:01:20Z /formatter_text_test.go:41 �[0;34mDEBUG�[0m Hello World year=2022

package main

import (
	"os"

	"github.com/actforgood/xlog"
)

func main() {
	// In this example we create a SyncLogger that writes logs
	// in logfmt format.

	opts := xlog.NewCommonOpts()
	opts.MinLevel = xlog.FixedLevelProvider(xlog.LevelDebug)
	opts.AdditionalKeyValues = []any{
		"appName", "demo",
		"env", "dev",
	}
	opts.Time = func() any { // mock time for output check
		return "2022-04-12T16:01:20Z"
	}
	opts.Source = xlog.SourceProvider(4, 1) // keep only filename for output check
	logger := xlog.NewSyncLogger(
		os.Stdout,
		xlog.SyncLoggerWithOptions(opts),
		xlog.SyncLoggerWithFormatter(xlog.LogfmtFormatter),
	)
	defer logger.Close()

	logger.Info(xlog.MessageKey, "Hello World", "year", 2022)

}

Output:

date=2022-04-12T16:01:20Z lvl=INFO src=/formatter_logfmt_test.go:43 appName=demo env=dev msg="Hello World" year=2022

// In this example we create a SyncLogger that sends logs to Sentry.

err := sentry.Init(sentry.ClientOptions{
	Dsn:         "https://examplePublicKey@o0.ingest.sentry.io/0",
	Environment: "dev",
	Release:     "v1.4.0",
})
if err != nil {
	panic(err)
}
sentry.ConfigureScope(func(scope *sentry.Scope) {
	scope.SetTag("appName", "demo")
})

opts := xlog.NewCommonOpts()
opts.MinLevel = xlog.FixedLevelProvider(xlog.LevelDebug)
logger := xlog.NewSyncLogger(
	io.Discard,
	xlog.SyncLoggerWithOptions(opts),
	xlog.SyncLoggerWithFormatter(xlog.SentryFormatter(
		xlog.JSONFormatter,
		sentry.CurrentHub().Clone(),
		opts,
	)),
)
defer func() {
	_ = logger.Close()
	_ = sentry.Flush(2 * time.Second)
}()

logger.Info(xlog.MessageKey, "Hello World", "year", 2022)

Output:

package main

import (
	"log/syslog"

	"github.com/actforgood/xlog"
)

func main() {
	// In this example we create a SyncLogger that logs to syslog.

	syslogWriter, err := syslog.Dial("", "", syslog.LOG_ERR, "demo")
	if err != nil {
		panic(err)
	}

	opts := xlog.NewCommonOpts()
	opts.MinLevel = xlog.FixedLevelProvider(xlog.LevelDebug)
	logger := xlog.NewSyncLogger(
		syslogWriter,
		xlog.SyncLoggerWithFormatter(xlog.SyslogFormatter(
			xlog.JSONFormatter,
			xlog.NewDefaultSyslogLevelProvider(opts),
			"",
		)),
		xlog.SyncLoggerWithOptions(opts),
	)
	defer func() {
		_ = logger.Close()
		_ = syslogWriter.Close()
	}()

	logger.Info(xlog.MessageKey, "Hello World", "year", 2022)

	// sudo tail -f /var/log/syslog
	// Apr  1 03:03:16 bogdan-Aspire-5755G demo[7572]: {"date":"2022-04-01T00:03:16.209891806Z","lvl":"INFO","msg":"Hello World","src":"/home/bogdan/work/go/xlog/formatter_decorator_syslog_test.go:45","year":2022}
}

Output:

package main

import (
	"log/syslog"

	"github.com/actforgood/xlog"
)

func main() {
	// In this example we create a SyncLogger that logs to syslog,
	// supporting all syslog levels. We can log extra syslog
	// levels with Log() method. This is just an example, based on "lvl"
	// key and Log() method.

	syslogWriter, err := syslog.Dial("", "", syslog.LOG_ERR, "demo")
	if err != nil {
		panic(err)
	}

	opts := xlog.NewCommonOpts()
	opts.MinLevel = xlog.FixedLevelProvider(xlog.LevelNone) // need LevelNone to be able to use Log().
	allSyslogLevelsMap := map[any]syslog.Priority{          // we define all levels map.
		// default xlog levels/labels
		"CRITICAL": syslog.LOG_CRIT,
		"ERROR":    syslog.LOG_ERR,
		"WARN":     syslog.LOG_WARNING,
		"INFO":     syslog.LOG_INFO,
		"DEBUG":    syslog.LOG_DEBUG,
		// define extra syslog levels which will be logged with Log()
		"EMERG":  syslog.LOG_EMERG,
		"ALERT":  syslog.LOG_EMERG,
		"NOTICE": syslog.LOG_NOTICE,
	}
	logger := xlog.NewSyncLogger(
		syslogWriter,
		xlog.SyncLoggerWithFormatter(xlog.SyslogFormatter(
			xlog.JSONFormatter,
			xlog.NewExtractFromKeySyslogLevelProvider( // we set syslog level provider
				opts.LevelKey,
				allSyslogLevelsMap,
			),
			"",
		)),
		xlog.SyncLoggerWithOptions(opts),
	)
	defer func() {
		_ = logger.Close()
		_ = syslogWriter.Close()
	}()

	// log xlog levels through dedicated APIs as usual.
	logger.Info(xlog.MessageKey, "Hello World", "year", 2022)
	// log extra syslog levels through Log().
	logger.Log("lvl", "NOTICE", xlog.MessageKey, "Hello World", "year", 2022)
}

Output: