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lgr - simple logger with some extras

install

go get github/go-pkgz/lgr

usage

    l := lgr.New(lgr.Debug, lgr.Caller) // allow debug and caller info
    l.Logf("INFO some important err message, %v", err)
    l.Logf("DEBUG some less important err message, %v", err)

output looks like this:

2018/01/07 13:02:34.000 INFO  {svc/handler.go:101 h.MyFunc1} some important err message, can't open file`
2018/01/07 13:02:34.015 DEBUG {svc/handler.go:155 h.MyFunc2} some less important err message, file is too small`

Without lgr.Caller it will drop {caller} part

details

interfaces and default loggers

• lgr package provides a single interface lgr.L with a single method Logf(format string, args ...interface{}). Function wrapper lgr.Func allows to make lgr.L from a function directly.
• Default logger functionality can be used without lgr.New, but just lgr.Printf
• Two predefined loggers available: lgr.NoOp (do-nothing logger) and lgr.Std (passing directly to stdlib log)

options

lgr.New call accepts functional options:

• lgr.Debug - turn debug mode on. This allows messages with "DEBUG" level (filtered overwise)
• lgr.Caller - adds the caller info each message
• lgr.Out(io.Writer) - sets the output writer, default os.Stdout
• lgr.Err(io.Writer) - sets the error writer, default os.Stderr

levels

lgr.Logf recognizes prefixes like "INFO" or "[INFO]" as levels. The full list of supported levels - "DEBUG", "INFO", "WARN", "ERROR", "PANIC" and "FATAL"

• DEBUG will be filtered unless lgr.Debug option defined
• INFO and WARN don't have any special behavior attached
• ERROR sends messages to both out and err writers
• "PANIC" and "FATAL" send messages to both out and err writers. In addition sends dump of callers and runtime info to err only, and call os.Exit(1).