localemu-examples

End-to-end working tutorials for LocalEmu, the open-source AWS emulator. Each folder is a self-contained project with real Terraform (or CloudFormation), real Lambda code, real integration tests, and a scripts/ directory you can run top to bottom. Every tutorial has been deployed, tested green, and torn down cleanly on LocalEmu.

The tutorials come in two shapes:

• Application patterns drive an end-to-end build with three scripts: deploy.sh (Terraform or CloudFormation), test.sh (pytest), and teardown.sh. A couple of edge-case patterns substitute setup.sh for deploy.sh or drop the provisioning step entirely; the per-folder README calls out the difference.
• Service demos are single-script walkthroughs: a demo.sh exercises the full scenario in one pass, and teardown.sh cleans up.

Tutorials

Application patterns (build, test, teardown)

Folder	What it builds
01-rest-api/	Five-route CRUD notes on API Gateway v2 + Lambda + DynamoDB
02-scheduled-job/	Hourly EventBridge Scheduler Lambda checking Secrets Manager rotation age
03-event-driven/	SNS fan-out with FilterPolicy to two SQS queues + two Lambdas (CloudFormation)
04-image-pipeline/	S3 upload to Lambda (Pillow thumbnail) to SNS + CloudWatch
05-batch-etl/	Step Functions Map over CSV rows with per-row Catch
06-s3-guardrail/	CloudTrail to EventBridge to Lambda auto-remediation of public S3 buckets
07-payment-ledger/	DynamoDB TransactWriteItems + Idempotency-Key + 5-way concurrent-debit race
08-llm-gateway/	Guardrailed, cached, evaluated LLM gateway (API GW + Lambda + DDB + EB + SQS + CW)
09-ci-cd/	Lambda handler unit tests against a LocalEmu service, runnable from any CI
10-microservices/	SNS + 2 SQS + 2 DynamoDB-table mini e-commerce wired up via plain aws CLI

Service demos (one-shot walkthroughs)

Folder	What it demonstrates	Required env
11-cognito-demo/	User pool + client + user lifecycle	none
12-kinesis-demo/	Stream create, PutRecord, GetRecords round-trip	none
13-opensearch-demo/	Domain create (real OpenSearch container), index, search	none
14-rds-demo/	Postgres + MySQL DB instances, psql + mysql clients, Python round-trip	RDS_DOCKER_BACKEND=1
15-ec2-demo/	RunInstances spins a real Docker container; SSH in via localemu ssh	none
16-ecs-demo/	Cluster + task definition + RunTask, real containers behind the API	none
17-eks-demo/	EKS cluster via k3d, kubectl apply, real pod deploy	none
18-transit-gateway-demo/	Three VPCs, TGW + peering, connectivity matrix verified end-to-end	none
19-iam-least-privilege/	Provably-minimum IAM policy via Sid-removal mutation testing	IAM_ENFORCEMENT=1
20-stepfunctions-saga/	Saga compensation across three failure injection points	none
21-chaos-resilience/	Load test with zero-data-loss assertion under retry pressure	none

All tutorials are tested end-to-end against both the pip install and the Docker image of LocalEmu.

Prerequisites

• Python 3.10+ with pytest, boto3, requests, Pillow (for the image-pipeline pattern)
• Terraform 1.5+
• The AWS CLI
• LocalEmu running locally on port 4566 (localemu start)

Usage

Application patterns (deploy.sh + test.sh + teardown.sh):

cd <tutorial-folder>
./scripts/deploy.sh    local   # or: aws
./scripts/test.sh      local
./scripts/teardown.sh  local

A few application patterns substitute setup.sh for deploy.sh or skip the provisioning step entirely; the per-folder README explains the deviation. The local / aws argument flips a single Terraform variable (or the --endpoint-url on CloudFormation patterns). Nothing else changes between targets.

Service demos:

cd <tutorial-folder>
./scripts/demo.sh
./scripts/teardown.sh

A handful require LocalEmu to be started with a specific env var (see the Service demos table above). The walkthrough's README.md repeats the prerequisite at the top.

License

Apache 2.0.