Gitlab CI/CD to deploy a Spring Boot application in AWS ECS with auto service restart

spring.boot.gitlab-ci.yml

image: docker:latest

variables:
  REGION: [aws region]

  REPOSITORY_URL: [your ECR repository url]
  REPOSITORY_NAME: [repository name]

  UAT_CLUSTER_NAME: [ECS Cluster name]
  UAT_SERVICE_NAME: [service name]
  UAT_TASK_DEFINTION_NAME: [task definition name]

  EXECUTION_ROLE: [ecsTaskExecutionRole]
  TASK_ROLE: [ecsTaskExecutionRole]


services:
  - docker:19.03.5-dind

before_script:
  - apk add --no-cache curl jq python py-pip
  - pip install awscli
  - $(aws ecr get-login --no-include-email --region "${REGION}")
  - IMAGE_TAG="$(echo $CI_COMMIT_SHA | head -c 8)"


stages:
  - test
  - build
  - deploy

test:
  stage: test
  script: echo "Running Test Cases"

build:
  stage: build
  script:
    - echo "Deleting old images..."
    - IMAGES_TO_DELETE=$( aws ecr list-images --region "${REGION}" --repository-name $REPOSITORY_NAME --filter tagStatus=UNTAGGED --query 'imageIds[*]' --output json )
    - echo $IMAGES_TO_DELETE
    - aws ecr batch-delete-image --region "${REGION}" --repository-name $REPOSITORY_NAME --image-ids "$IMAGES_TO_DELETE" || true
    - echo "Building image..."
    - docker build -f ./Dockerfile -t $REPOSITORY_URL:latest .
    - echo "Tagging image..."
    - docker tag $REPOSITORY_URL:latest $REPOSITORY_URL:$IMAGE_TAG
    - echo "Pushing image..."
    - $(aws ecr get-login --no-include-email --region "${REGION}")
    - docker push $REPOSITORY_URL:latest
  only:
    - master

deploy_uat:
  stage: deploy
  script:
    - echo $REPOSITORY_URL:$IMAGE_TAG
    - TASK_DEFINITION=$(aws ecs describe-task-definition --task-definition "$UAT_TASK_DEFINTION_NAME" --region "${REGION}")
    - NEW_CONTAINER_DEFINTIION=$(echo $TASK_DEFINITION | python $CI_PROJECT_DIR/update_task.py $REPOSITORY_URL:latest)
    - echo "Registering new container definition...."
    - echo "${NEW_CONTAINER_DEFINTIION}"
    - aws ecs register-task-definition --region "${REGION}" --execution-role-arn "${EXECUTION_ROLE}" --task-role-arn "${TASK_ROLE}" --cpu 256 --memory 512 --network-mode "awsvpc" --requires-compatibilities "FARGATE" --family "${UAT_TASK_DEFINTION_NAME}" --container-definitions "${NEW_CONTAINER_DEFINTIION}"
    - echo "Updating the service..."
    - aws ecs update-service --region "${REGION}" --cluster "${UAT_CLUSTER_NAME}" --service "${UAT_SERVICE_NAME}"  --task-definition "${UAT_TASK_DEFINTION_NAME}"
  only:
    - master

#Production:
#  stage: deploy
#  script:
#    - echo $REPOSITORY_URL:$IMAGE_TAG
#    - TASK_DEFINITION=$(aws ecs describe-task-definition --task-definition "$PROD_TASK_DEFINTION_NAME" --region "${REGION}")
#    - NEW_CONTAINER_DEFINTIION=$(echo $TASK_DEFINITION | python $CI_PROJECT_DIR/update_task_definition_image.py $REPOSITORY_URL:latest)
#    - echo "Registering new container definition...."
#    - echo "${NEW_CONTAINER_DEFINTIION}"
#    - aws ecs register-task-definition --region "${REGION}" --execution-role-arn "${EXECUTION_ROLE}" --task-role-arn "${TASK_ROLE}" --network-mode "awsvpc" --requires-compatibilities "EC2" --family "${PROD_TASK_DEFINTION_NAME}" --container-definitions "${NEW_CONTAINER_DEFINTIION}"
#    - echo "Updating the service..."
#    - aws ecs update-service --region "${REGION}" --cluster "${PROD_CLUSTER_NAME}" --service "${PROD_SERVICE_NAME}"  --task-definition "${PROD_TASK_DEFINTION_NAME}"
#  only:
#    - master
#  when: manual

Content of update_task.py

`import sys, json, argparse

parser = argparse.ArgumentParser('Replaces image in the task definition')
parser.add_argument('image_uri', metavar='I', type=str, nargs='+',
                   help='The new image URI')

args = parser.parse_args()

definition = json.load(sys.stdin)['taskDefinition']['containerDefinitions']
definition[0]['image'] = args.image_uri[0]

definition[0]['cpu'] =256
definition[0]['memory'] =512

print json.dumps(definition)`