I'm using the below configuration where multiple files are in use for writing logs. However with the SetFlags options in place, I noticed that only first file adhere to the settings. Rest of the files fall back to generic option where the "code line numbers" are being printed.

Code Snippet (Initializing files and logger):

lf2, err := os.OpenFile("log/server.log", os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0660)
if err != nil {
	logger.Fatalf("Failed to open log file: %v", err)
}
defer lf2.Close()
lf3, err := os.OpenFile("log/auth.log", os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0660)
if err != nil {
	logger.Fatalf("Failed to open log file: %v", err)
}
defer lf3.Close()
glogger = logger.Init("Websockets Logger", false, false, lf)
defer glogger.Close()

Ologger = logger.Init("General Logger", false, false, lf2)
defer Ologger.Close()

userlogger = logger.Init("Authentication Logger", false, false, lf3)
defer userlogger.Close()

Code Snippet: (Initializing logger flags)
logger.SetFlags(log.LstdFlags | log.LUTC)

Fatal/Fatalf calls os.Exit immediately, which won't allow any unwritten log to be flushed to disk.

We should try to close the log files before exit.

Logger library is working as expected in Linux (Ubuntu 18.04 LTS) and in Mac os but
when I am running it in docker having alpine Linux as a base image, it is stuck at

logger.Init("foo", *verbose, true, lf)

I am using its latest version by downloading it using go get github.com/google/logger

It's blocking the entire application as the func logger.Init() is not returning.

My implementation:

func mustInitLogger() *logger.Logger {
	fmt.Printf("initializing x-microservice application log\n")
	lf, err  := os.OpenFile(logPath, os.O_CREATE|os.O_WRONLY|os.O_APPEND, 0644)
	if err != nil {
		panic(err)
	}
	fmt.Printf("log file created, initializing x-microservice logger instance\n")
	logr := logger.Init("x-microservice", true, true, lf)
	logger.SetFlags(log.LstdFlags)
	fmt.Printf("log initialization done\n")
	return logr
}

Update:

When I switched to version v1.0.1, I get this error:

unix syslog delivery error

output by default

INFO : 2018/09/26 06:00:06.607994 test.go:25: hello

how to remove date info and test.go:25 just need "hello"

Log depth is currently fixed for inferring logging file and line number, which is not very handy in the case where a helper function wants to log as the caller. For instance:

func retry(fn func() error) error {
  for attempt := 0; ; {
    if attempt > 0 {
      time.Sleep(backoff(attempt))
      logger.InfoDepth(1, fmt.Sprintf("Retry %d", attempt)) // logging from this line doesn't correct reflect the context.
    }
    err := fn()
    if err == nil {
       return nil
    }
    if !isRetryable(err) {
       return err
    }
    logger.InfoDepth(1, fmt.Sprintf("Got retryable error: %v", err)) // ditto
  }
  return nil
}

if err := retry(func() error {
  httpClient.Do(...)
}); err != nil {
  // ..
}

Currently all logs generated by the logger package are fixed with the following format:
INFO : 2018/03/08 14:40:40.643151 filename.go:100: some message...

It would be great to be able to define the flags that are passed to the log package when initializing the logger instance, in order to define the format of the logged messages.

Hello everyone,
I want write log Info, log error. I don't want write log debug. What should I do?

Thanks!

Was wandering the your source code, and saw this very minor one:

// simultaneously even if they are using the same same writers.
                                                  ^^^^

https://github.com/google/logger/blob/master/logger.go#L145

It is impossible to use any google/logger based package (e.g. https://github.com/google/go-sev-guest) when compiling to WASM, since google/logger does not provide a default setup function:

GOARCH=wasm GOOS=js go run -exec="/usr/local/go/misc/wasm/go_js_wasm_exec" ./examples/client
# github.com/google/logger
/home/sza-1/go/pkg/mod/github.com/google/[email protected]/logger.go:81:27: undefined: setup

well i saw no way to set a flag or other option to prevent ERROR messages printing in console.
I would like all logger messages to be only in a file

verbose false and system false did not help

Logger is useful for handling logging to Windows EventLog, but unfortunately the event IDs used by logger are hardcoded and not configurable by the user. It would be greatly preferable to have a way to set a unique event ID for each log message, so logs that are aggregated can be filtered effectively.

Getting:
google/logger/logger.go:81:21: undefined: setup
when running go get github.com/google/logger

go version go1.11.4 linux/amd64

When I try to run the demo in the README.md, I found a little mistake.
If I replace defer lf.Close() with

defer func() {  
    if err := lf.Close(); err != nil {  
        panic(err)
    }  
}  

I will get err msg like this: file already be closed!

Please add semantic versioning so that go mod doesnt points to an arbitrary commit in master branch.