Golang logging: Difference between revisions
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<syntaxhighlight lang="go"> | <syntaxhighlight lang="go"> | ||
import "os" | |||
import "io/ioutil" | |||
import "log" | |||
logFmt := log.Ldate|log.Ltime|log.Llongfile | logFmt := log.Ldate|log.Ltime|log.Llongfile | ||
InfoLogger := log.New(os.Stderr, "INFO:", logFmt) | InfoLogger := log.New(os.Stderr, "INFO: ", logFmt) | ||
ErrorLogger := log.New(os.Stderr, "ERROR: ", logFmt) | |||
DebugLogger := log.New(ioutil.Discard, "DEBUG: ", logFmt) // redirects to /dev/null | |||
</syntaxhighlight> | </syntaxhighlight> | ||
</blockquote><!-- LogLevels --> | </blockquote><!-- LogLevels --> |
Revision as of 22:22, 18 June 2022
Logging is a standardized format of writing progress/debug info.
Documentation
log
https://pkg.go.dev/log logfmt flags https://pkg.go.dev/log#pkg-constants
Basics
Go creates a logger that logs to stderr by default.
If you like, you can modify it's logformat.
There are no log-levels by default.// customize default log's logformat log.SetFlags(log.Ldate|log.Ltime|log.Llongfile) // log methods similar to 'fmt.*' methods log.Println("application started") // log message log.Fatalln("application exiting") // os.Exit(1) after logged log.Panicln("application panicked") // panic() after logged
LogLevels
Go doesn't provide log-levels, but you can create separate loggers to implement this yourself.
You don't need to do this in every file, log-format flags indicating filepath will use the correct path where it is called from.import "os" import "io/ioutil" import "log" logFmt := log.Ldate|log.Ltime|log.Llongfile InfoLogger := log.New(os.Stderr, "INFO: ", logFmt) ErrorLogger := log.New(os.Stderr, "ERROR: ", logFmt) DebugLogger := log.New(ioutil.Discard, "DEBUG: ", logFmt) // redirects to /dev/null