Read first:

PART 1: How I designed and deployed a scalable microservice architecture with limited resources
PART 2: Setting up CI/CD Pipeline for a Monolithic Service

In the last part we set up our pipeline for a Monolithic Architecture, but that’s not what I promised in the first part of the series.

Let’s get going…

Off to decoupling our services, so that they can live freely once again.

Well, that’s easy. Create a separate repository for each service, copy the workflow files to each of them. You are done! Ok, bye.

No, definitely not.

You can use that setup if all you have to do is run unit tests, but what about integration testing. Can’t do that on the production instance, and you are a struggling startup; you don’t have enough resources to spin up more instances just to run integration tests.

Well?

Ok, we will be putting each service in its own separate remote repository, but we will have one parent repository that refers to all the services’ repositories.

Let’s get started with git submodules…

Git Submodules are a way of adding a git repository inside a git repository. All submodules point to a commit in the remote repository.

The original intention behind git submodules was to keep a copy of a certain commit (or release) locally on which our project might depend.

You just need to run:

git submodule add <my-remote> <optional-path>

However, we need them to keep up-to-date with our services’ repository, that’s why it’s a good thing that we can make them point to a certain branch instead too.

git config -f .gitmodules submodule.<submodule-name>.branch <branch-name>

Now, you can keep all your submodules up-to-date with just one command

git submodule update --remote

Now, that git submodules are out of the way, let’s get to the actual “good” stuff.

Ok, let’s talk about the actual workflow that I follow:

Each service’s repository contains its unit test
After a commit is pushed to the service’s repository, it runs its unit tests.
If all the unit test pass, then we commit it to the parent repository.

_<submodule>/.github/workflows/test-and-push.yml_

      
        name: CI/CD Deployment
      
        on: [push]
      
        jobs:
      
          buildAndTest:
      
            name: CI Pipeline
      
            runs-on: ubuntu-latest
      
            strategy:
      
              matrix:
      
                node-version: ['12.x']
      
            steps:
      
              - uses: actions/checkout@v2
      
              # Initialize Node.js
      
              - name: Install Node.js ${{ matrix.node-version }}
      
                uses: actions/setup-node@v1
      
                with:
      
                  node-version: ${{ matrix.node-version }}
      
              # Install project dependencies and test
      
              - name: Install dependencies
      
                run: npm install
      
              - name: Run tests
      
                run: npm run test
      
           push:
      
            name: Deploy
      
            runs-on: ubuntu-latest
      
            needs: buildAndTest
      
            steps:
      
            - name: Checkout
      
              uses: actions/checkout@v2
      
            # Clone the parent repo
      
            - name: Clone Parent
      
              env:
      
                GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
      
              run: |
      
                git clone --recursive <parent-repo-remote>
      
            # Confifure username and email
      
            - name: Config username
      
              run: |
      
                git config --global user.name '<your-name>'
      
                git config --global user.email '<your-email>'
      
            # Commit and push changes
      
            - name: Commit and push
      
              env:
      
                GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
      
              run: |
      
                git add .
      
                git commit -m "Updated Tracking ${{ github.sha }}"
      
                git push origin master

view raw test-and-push.yml hosted with ❤ by GitHub

The parent repo lists the submodules where the changes were made since the last push and only deploys those services again.

<parent-repo>/.github/workflows/deploy.yml

      
        name: CI/CD Deployment
      
        on: [push]
      
        jobs:
      
            deploy:
      
                name: Deploy
      
                runs-on: ubuntu-latest
      
                strategy:
      
                    matrix:
      
                        python-version: [3.8]
      
                        node-version: ['12.x']
      
                        appname: ['my-application-codedeploy']
      
                        deploy-group: ['prod']
      
                        s3-bucket:
      
                            ['my-application-codedeploys']
      
                        s3-filename:
      
                            ['prod-aws-codedeploy-${{ github.sha }}']
      
                steps:
      
                    - name: Checkout
      
                      uses: actions/checkout@v2
      
                      with:
      
                          fetch-depth: 0
      
                          submodules: 'true'
      
                          token: ${{ secrets.PAT }} # Defining PAT to fetch private submodules
      
                    - name: Configure AWS credentials
      
                      uses: aws-actions/configure-aws-credentials@v1
      
                      with:
      
                          aws-access-key-id: ${{ secrets.AWS_ACCESS_KEY_ID }}
      
                          aws-secret-access-key: ${{ secrets.AWS_SECRET_ACCESS_KEY }}
      
                          aws-region: ${{ secrets.AWS_REGION }}
      
                    - name: AWS Deploy
      
                      env:
      
                          AWS_APP_NAME: ${{ matrix.appname }}
      
                          AWS_DEPLOY_GROUP: ${{ matrix.deploy-group }}
      
                          AWS_BUCKET_NAME: ${{ matrix.s3-bucket }}
      
                          AWS_FILENAME: ${{ matrix.s3-filename }}
      
                          GITHUB_EVENT_BEFORE: ${{ github.event.before }}
      
                          GITHUB_SHA: ${{ github.sha }}
      
                      run: |
      
                          sudo chmod +x ./scripts/deploy.sh
      
                          ./scripts/deploy.sh

view raw deploy.yml hosted with ❤ by GitHub

This way all the other services keep running without any disturbance, while one of the service is updated.

<parent-repo>/scripts/deploy.sh

      
        # /bin/bash
      
        # Getting all the submodules(directories)/files where changes were made
      
        temp=("$(git diff-tree --submodule=diff --name-only ${GITHUB_EVENT_BEFORE} ${GITHUB_SHA})")
      
        echo $temp
      
        # Keeping only distinct values in the array
      
        UNIQ_SUBS=($(echo "${temp[@]}" | tr ' ' '\n' | sort -u | tr '\n' ' '))
      
        for SUB in ${UNIQ_SUBS[@]}
      
        do
      
            if [ -d "$SUB" ]
      
            then
      
                cd ${SUB}
      
                if [ ! -f "appspec.yml" ]
      
                then
      
                    echo $PWD
      
                    echo "AppSpec.yml not found in ${SUB}"
      
                    continue
      
                fi
      
            else 
      
                continue
      
            fi
      
            chmod +x ../scripts/get_env.sh
      
            ../scripts/get_env.sh ${SUB}
      
            aws deploy push \
      
                --application-name ${AWS_APP_NAME} \
      
                --description "Revision for the ${SUB}-${AWS_APP_NAME}" \
      
                --no-ignore-hidden-files \
      
                --s3-location s3://${AWS_BUCKET_NAME}/${SUB}-${AWS_FILENAME}.zip \
      
                --source .
      
            aws deploy create-deployment \
      
                --application-name ${AWS_APP_NAME} \
      
                --deployment-config-name CodeDeployDefault.OneAtATime \
      
                --deployment-group-name ${SUB}-${AWS_DEPLOY_GROUP} \
      
                --file-exists-behavior OVERWRITE \
      
                --s3-location bucket=${AWS_BUCKET_NAME},key=${SUB}-${AWS_FILENAME}.zip,bundleType=zip
      
            cd ..
      
        done

view raw deploy.sh hosted with ❤ by GitHub

I also created separate Deployment Groups for each service of the name: _<service-name>-prod_, i.e. for _nodeauth_ service, I created a _nodeauth-prod_ deployment group, with rest of the configuration same as we did in the previous part.

We also do need to modify the appspec.yml and our scripts.

Since each service is a separate deployment, we need to put the appspec.yml in each service's repository.

      
        version: 0.0
      
        os: linux
      
        files:
      
            - source: /
      
              destination: /home/ubuntu/my-application/my-submodule-1
      
        hooks:
      
            BeforeInstall:
      
                - location: ./scripts/init.sh
      
                  timeout: 300
      
                  runas: root
      
            ApplicationStart:
      
                - location: ./scripts/start_app.sh
      
                  timeout: 300
      
                  runas: root
      
            ApplicationStop:
      
                - location: ./scripts/cleanup.sh
      
                  timeout: 300
      
                  runas: root

view raw appspec.yml hosted with ❤ by GitHub

Since we have decoupled all the services from each other, we no longer run them using sudo docker-compose up, each service has to be started individually.

<submodule>/scripts/start_app.sh

      
        SERVICE_NAME=${DEPLOYMENT_GROUP_NAME%-*}
      
        # Change directory into the service folder
      
        cd /home/ubuntu/tastebuds-backend/${SERVICE_NAME}/
      
        # Read env variables from .env file
      
        export $(cat .env | xargs)
      
        # Remove the previous container
      
        sudo docker stop ${SERVICE_NAME}
      
        sudo docker rm ${SERVICE_NAME}
      
        # Create a default network to connect the services
      
        sudo docker network create ${NETWORK}
      
        # Build the docker image
      
        sudo docker build -t ${SERVICE_NAME} .
      
        # Run the container
      
        if [ -z ${VOLUME} ]
      
        then 
      
            sudo docker run --rm -d -p ${PORT}:${PORT} --network ${NETWORK} --name ${SERVICE_NAME} ${SERVICE_NAME}
      
        else
      
            sudo docker run --rm -d -p ${PORT}:${PORT} -v $(pwd)/${VOLUME} --network ${NETWORK} --name ${SERVICE_NAME} ${SERVICE_NAME}
      
        fi
      
        # unset env variables
      
        unset $(grep -v '^#' .env | sed -E 's/(.*)=.*/\1/' | xargs)

view raw start_app.sh hosted with ❤ by GitHub

I wrote a bit complex script so that we can use the same set of scripts in all our services instead of writing them again and again as new services are added.
The scripts can also be added as a git submodule to all the services’ repositories, which makes it easier to maintain (but they weren’t in my setup at the moment of writing this blog).
init.sh contains code to install docker on the instance (if not already present).
cleanup.sh contains code to remove the previous unused containers.

That’s it. You are finally done. You’ve got your own weird-ass setup to test and deploy a Microservice Architecture at zero cost. You can also keep the previous docker-compose.yml to maintain a local development setup.

The single instance’s cost is covered under AWS free-tier.

disclaimer: Yes, there is probably a better way of doing this. I hope there is.

ShauryaAg

Contact

	name: CI/CD Deployment

	on: [push]

	jobs:
	buildAndTest:
	name: CI Pipeline
	runs-on: ubuntu-latest
	strategy:
	matrix:
	node-version: ['12.x']

	steps:
	- uses: actions/checkout@v2

	# Initialize Node.js
	- name: Install Node.js ${{ matrix.node-version }}
	uses: actions/setup-node@v1
	with:
	node-version: ${{ matrix.node-version }}

	# Install project dependencies and test
	- name: Install dependencies
	run: npm install
	- name: Run tests
	run: npm run test

	push:
	name: Deploy
	runs-on: ubuntu-latest

	needs: buildAndTest
	steps:
	- name: Checkout
	uses: actions/checkout@v2

	# Clone the parent repo
	- name: Clone Parent
	env:
	GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
	run: \|
	git clone --recursive <parent-repo-remote>

	# Confifure username and email
	- name: Config username
	run: \|
	git config --global user.name '<your-name>'
	git config --global user.email '<your-email>'

	# Commit and push changes
	- name: Commit and push
	env:
	GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
	run: \|
	git add .
	git commit -m "Updated Tracking ${{ github.sha }}"
	git push origin master

	# /bin/bash

	# Getting all the submodules(directories)/files where changes were made
	temp=("$(git diff-tree --submodule=diff --name-only ${GITHUB_EVENT_BEFORE} ${GITHUB_SHA})")

	echo $temp

	# Keeping only distinct values in the array
	UNIQ_SUBS=($(echo "${temp[@]}" \| tr ' ' '\n' \| sort -u \| tr '\n' ' '))

	for SUB in ${UNIQ_SUBS[@]}
	do
	if [ -d "$SUB" ]
	then
	cd ${SUB}
	if [ ! -f "appspec.yml" ]
	then
	echo $PWD
	echo "AppSpec.yml not found in ${SUB}"
	continue
	fi
	else
	continue
	fi

	chmod +x ../scripts/get_env.sh
	../scripts/get_env.sh ${SUB}

	aws deploy push \
	--application-name ${AWS_APP_NAME} \
	--description "Revision for the ${SUB}-${AWS_APP_NAME}" \
	--no-ignore-hidden-files \
	--s3-location s3://${AWS_BUCKET_NAME}/${SUB}-${AWS_FILENAME}.zip \
	--source .

	aws deploy create-deployment \
	--application-name ${AWS_APP_NAME} \
	--deployment-config-name CodeDeployDefault.OneAtATime \
	--deployment-group-name ${SUB}-${AWS_DEPLOY_GROUP} \
	--file-exists-behavior OVERWRITE \
	--s3-location bucket=${AWS_BUCKET_NAME},key=${SUB}-${AWS_FILENAME}.zip,bundleType=zip

	cd ..

	done

	version: 0.0
	os: linux
	files:
	- source: /
	destination: /home/ubuntu/my-application/my-submodule-1
	hooks:
	BeforeInstall:
	- location: ./scripts/init.sh
	timeout: 300
	runas: root
	ApplicationStart:
	- location: ./scripts/start_app.sh
	timeout: 300
	runas: root
	ApplicationStop:
	- location: ./scripts/cleanup.sh
	timeout: 300
	runas: root

	SERVICE_NAME=${DEPLOYMENT_GROUP_NAME%-*}

	# Change directory into the service folder
	cd /home/ubuntu/tastebuds-backend/${SERVICE_NAME}/

	# Read env variables from .env file
	export $(cat .env \| xargs)

	# Remove the previous container
	sudo docker stop ${SERVICE_NAME}
	sudo docker rm ${SERVICE_NAME}

	# Create a default network to connect the services
	sudo docker network create ${NETWORK}

	# Build the docker image
	sudo docker build -t ${SERVICE_NAME} .

	# Run the container
	if [ -z ${VOLUME} ]
	then
	sudo docker run --rm -d -p ${PORT}:${PORT} --network ${NETWORK} --name ${SERVICE_NAME} ${SERVICE_NAME}
	else
	sudo docker run --rm -d -p ${PORT}:${PORT} -v $(pwd)/${VOLUME} --network ${NETWORK} --name ${SERVICE_NAME} ${SERVICE_NAME}
	fi

	# unset env variables
	unset $(grep -v '^#' .env \| sed -E 's/(.)=./\1/' \| xargs)