foae / clogger

Context aware logging library written with Go

clogger

Clogger is a context aware, structured logging library written in Go.

It has the following output formatters

1. GCP Stackdriver
2. JSON
3. Terminal (human friendly output)

It offers out of the box tracing

• OpenCensus
• OpenTelemetry

How to set up a new logger

package main

import log "github.com/foae/clogger"

func main() {
	// Create a new default logger
	logger := log.NewDefaultLogger()

	// We want the output to be human-readable 
	// – we choose a terminal encoder 
	logger.SetEncoder(&log.TerminalEncoder{})

	// For each and every EVENT, we can choose 
	// decorators or write our own.
	logger.SetEventOptions(log.WithOpenTelemetryTrace(), log.WithExampleEventOption())

	// For each and every LOG ENTRY, we can choose 
	// decorators or write our own.
	logger.SetLogEntryOptions(log.WithOpenCensusSpan())

	// Everything is configured, stored it globally for later use
	log.SetGlobal(logger)
}

How to use the library

1. Creating new Events

package main

import (
	"context"

	log "github.com/foae/clogger"
)

func handlePOST(ctx context.Context) {
	ctx, event := log.NewEvent(ctx, "Received a new POST request")
	defer event.End()

	// Attach data directly to the event
	event.Set("key", "value")
	event.SetOnErr("key", "value")
	event.SetLabel("key", "value")

	// ... TODO: add more examples, explain what each Set* is doing
}

2. Logging fields

// consider: import log "github.com/foae/clogger"
// consider: ctx exists

log.Debug(ctx, "A debug statement")
log.With("user_id", userID).Debug(ctx, "A debug statement")

Terminology

• Events
  • Set
  • SetOnErr
  • SetLabel
• Log entries
  • Fields

Work In Progress.

Current state: alpha