Getting Localstack Up and Running

In continuation to the earlier post on mocks for clouds, this article does a deep dive into getting up & running with Localstack. This is a consolidation of the steps & best practices shared here, here & here. The Localstack set-up is on a Ubuntu-20.04, with Java-8x, Maven-3.8x, Docker-24.0x. 

(I) Set-up

    # Install awscli
     sudo apt-get install awscli

    # Install localstack ver 3.8
        ## Issue1: By default pip pulls in version 4.0, which gives an error:
        ## ERROR: Could not find a version that satisfies the requirement localstack-ext==4.0.0 (from localstack) 

        python3 -m pip install localstack==3.8.1

--

    # Add to /etc/hosts
    127.0.0.1    localhost.localstack.cloud
    127.0.0.1    s3.localhost.localstack.cloud

--

    # Configure AWS from cli
    aws configure
    aws configure set default.region us-east-1
    aws configure set aws_access_key_id test
    aws configure set aws_secret_access_key test

    ## Manually configure AWS
    Add to ~/.aws/config
    endpoint_url = http://localhost:4566

    ## Add mock credentials
    Add to ~/.aws/credentials
    aws_access_key_id = test
    aws_secret_access_key = test

--

    # Download docker images needed by the Lambda function
        ## Issue 2: Do this before hand, Localstack gets stuck
        ## at the download image stage unless it's already available

    ## Pull java:8.al2
    docker pull public.ecr.aws/lambda/java:8.al2

    ## Pull nodejs (required for other nodejs Lambda functions)
    docker pull public.ecr.aws/lambda/nodejs:18

    ## Check images downloaded
    docker image ls

(II) Start Localstack

    # Start locally
    localstack start

    # Start as docker (add '-d' for daemon)
       ## Issue 3: Local directory's mount should be as per sample docker-compose

    docker-compose -f docker-compose-localstack.yaml up

    # Localstack up on URL's
    http://localhost:4566
    http://localhost.localstack.cloud:4566

    # Check Localstack Health
    curl http://localhost:4566/_localstack/info
    curl http://localhost:4566/_localstack/health

(III) AWS services on Localstack from CLI

  (a) S3
    # Create bucket named "test-buck"
    aws --endpoint-url=http://localhost:4566 s3 mb s3://test-buck

    # Copy item to bucket
    aws --endpoint-url=http://localhost:4566 s3 cp a1.txt s3://test-buck

    # List bucket
    aws --endpoint-url=http://localhost:4566 s3 ls s3://test-buck

--

  (b) Sqs
    # Create queue named "test-q"
    aws --endpoint-url=http://localhost:4566 sqs create-queue --queue-name test-q

    # List queues
    aws --endpoint-url=http://localhost:4566 sqs list-queues

    # Get queue attribute
    aws --endpoint-url=http://localhost:4566 sqs get-queue-attributes --queue-url http://sqs.us-east-1.localhost.localstack.cloud:4566/000000000000/test-q --attribute-names All

--

  (c) Lambda
    aws --endpoint-url=http://localhost:4566 lambda list-functions

    # Create Java function
    aws --endpoint-url=http://localhost:4566 lambda create-function --function-name test-j-div --zip-file fileb://original-java-basic-1.0-SNAPSHOT.jar --handler example.HandlerDivide::handleRequest --runtime java8.al2 --role arn:aws:iam::000000000000:role/lambda-test

    # List functions
    aws --endpoint-url=http://localhost:4566 lambda list-functions

    # Invoke Java function
    aws --endpoint-url=http://localhost:4566 lambda invoke --function-name test-j-div --payload '[200,9]' outputJ.txt

    # Delete function
    aws --endpoint-url=http://localhost:4566 lambda delete-function --function-name test-j-div

(IV) AWS services on Localstack from Java-SDK

    # For S3 & Sqs - localstack-aws-sdk-examples, java sdk

    # For Lambda - localstack-lambda-java-sdk-v1