logger

README

Golang Lambda Logger

This module provides logging functions that are compatible with AWS lambda advanced logging controls.

It supports both Text format as well as JSON format.

Features

• supports structured logging with key-value data
• automatically adds Lambda requestId to log entries
• automatically adds XRay traceId to log entries

Configuration

This module does not provide any configuration or special settings. It uses Lambda settings to configure itself.

Installation and Usage

Require the module using import logger "github.com/CuracadoGit/go-lambda-logger", then use the alias logger.xyz in your code.

This module provides functions corresponding to these log levels:

• Debug
• Info
• Error
• Warning

Example:

package main

import (
	"context"
	logger "github.com/CuracadoGit/go-lambda-logger"
	"github.com/aws/aws-lambda-go/lambdacontext"
)

func main() {
	ctx := context.TODO()

	ctx = lambdacontext.NewContext(ctx, &lambdacontext.LambdaContext{AwsRequestID: "8f507cfc-xmpl-4697-b07a-ac58fc914c95"})
	ctx = context.WithValue(ctx, "x-amzn-trace-id", "Root=1-5759e988-bd862e3fe1be46a994272793;Sampled=1")

	user := struct {
		ID    string
		Name  string
		Email string
	}{
		"user-123-abc", "User Name", "user-email@email.test",
	}

	logger.Info(ctx, "user has been created successfully", "userID", user.ID, "user_data", user)
}

Using the default Text format, this will in a result like this: 2024-11-15T10:50:09.01298877+01:00 8f507cfc-xmpl-4697-b07a-ac58fc914c95 INFO user has been created successfully {"traceId":"1-5759e988-bd862e3fe1be46a994272793","userID":"user-123-abc","user_data":{"Email":"user-email@email.test","ID":"user-123-abc","Name":"User Name"}}

When JSON formatting is enabled in your Lambda then the following output should be visible: {"timestamp":"2024-11-15T10:52:12.212202617+01:00","level":"INFO","message":"user has been created successfully","userID":"user-123-abc","user_data":{"ID":"user-123-abc","Name":"User Name","Email":"user-email@email.test"},"requestId":"8f507cfc-xmpl-4697-b07a-ac58fc914c95","traceId":"1-5759e988-bd862e3fe1be46a994272793"}

Restrictions

Currently, this module only supports the same log level as slog does. This causes a mismatch between this module anc AWS. Notably, these two levels are not supported:

• TRACE
• FATAL

Documentation

Overview

Package logger provides basis logging functions for Lambdas written in Golang.

The output is compatible with AWS structured JSON logging. All log records will include Lambda requestIDs and X-Ray traceIDs if present in the context.

Use `go get` to include the module in your code.

go get github.com/CuracadoGit/go-lambda-logger

Package logger

Index

• Variables
• func Debug(ctx context.Context, msg string, args ...any)
• func Error(ctx context.Context, msg string, args ...any)
• func Info(ctx context.Context, msg string, args ...any)
• func Warning(ctx context.Context, msg string, args ...any)
• func WithContextValues(ctx context.Context, data map[string]interface{}) context.Context

Variables

var Version = "v1"

Functions

func Debug

func Debug(ctx context.Context, msg string, args ...any)

func Error

func Error(ctx context.Context, msg string, args ...any)

func Info

func Info(ctx context.Context, msg string, args ...any)

func Warning

func Warning(ctx context.Context, msg string, args ...any)

func WithContextValues

func WithContextValues(ctx context.Context, data map[string]interface{}) context.Context

WithContextValues will add additional values to the context. These values will be added to all log entries using the context.