awsim

A lightweight AWS service emulator written in Go. Designed for CI/CD environments where authentication-free local AWS testing is needed.

Features

• No authentication required - Perfect for CI environments
• Single binary - Easy to distribute and deploy
• Docker support - Run as a container
• Lightweight - Fast startup, minimal resource usage

Supported Services

Phase 1 (Current)

• S3 - Object storage
• SQS - Message queuing
• DynamoDB - NoSQL database
• Secrets Manager - Secret storage
• SSM Parameter Store - Configuration management

Phase 2 (Planned)

• SNS - Pub/Sub messaging
• CloudWatch Logs - Logging
• IAM - Identity management
• Lambda - Serverless functions

Phase 3 (Future)

• API Gateway
• EventBridge
• Step Functions
• Kinesis
• CloudFormation

Quick Start

Binary

# Build
make build

# Run
./bin/awsim

Docker

# Build image
make docker

# Run container
docker run -p 4566:4566 awsim:0.1.0

Usage with AWS SDK

package main

import (
    "context"
    "github.com/aws/aws-sdk-go-v2/aws"
    "github.com/aws/aws-sdk-go-v2/config"
    "github.com/aws/aws-sdk-go-v2/service/s3"
)

func main() {
    cfg, _ := config.LoadDefaultConfig(context.TODO(),
        config.WithRegion("us-east-1"),
    )

    client := s3.NewFromConfig(cfg, func(o *s3.Options) {
        o.BaseEndpoint = aws.String("http://localhost:4566")
        o.UsePathStyle = true
    })

    // Use client as normal
}

Configuration

Environment variables:

Variable	Default	Description
AWSIM_HOST	0.0.0.0	Server bind address
AWSIM_PORT	4566	Server port
AWSIM_LOG_LEVEL	info	Log level (debug, info, warn, error)
AWSIM_STORAGE	memory	Storage backend (memory, file)

Development

# Run tests
make test

# Run with coverage
make test-cover

# Lint
make lint

# Format
make fmt

License

MIT License