AWS ECS Deployment script for updating existing service from creating new revision of existing task definition

ecs-deploy.sh

#!/bin/bash

helpFunction() {
  echo ""
  echo "Pass AWS credentials through environment variables"
  echo ""
  echo "Usage: $0 -r aws-region -c my-cluster -s my-ecs-service -i my-image-id -t my-image-tag"
  echo -e "\t-r AWS Region"
  echo -e "\t-c AWS ECS Cluster name"
  echo -e "\t-s AWS ECS Service name"
  echo -e "\t-i Docker image ID"
  echo -e "\t-t Docker image tag"
  exit 1 # Exit script after printing help
}

while getopts "r:c:s:i:t:" opt; do
  case "$opt" in
  r) AWS_REGION="$OPTARG" ;;
  c) CLUSTER="$OPTARG" ;;
  s) SERVICE="$OPTARG" ;;
  i) IMAGE="$OPTARG" ;;
  t) TAG="$OPTARG" ;;
  ?) helpFunction ;; # Print helpFunction in case parameter is non-existent
  esac
done

# Print helpFunction in case parameters are empty
if [ -z "$AWS_REGION" ] || [ -z "$CLUSTER" ] || [ -z "$SERVICE" ] || [ -z "$IMAGE" ] || [ -z "$TAG" ]; then
  echo "Some or all of the parameters are empty"
  helpFunction
fi

# Populate variable with service description
SRV_DESCR=$(aws ecs describe-services --region "${AWS_REGION}" \
  --cluster "${CLUSTER}" \
  --services "${SERVICE}")

# Get current task definition arn from service description
CURR_TASK_DEF_ARN=$(echo "$SRV_DESCR" | jq -r ".services[0].taskDefinition")

# Get current task definition json
CURR_TASK_DEF_JSON=$(aws ecs describe-task-definition \
  --region "${AWS_REGION}" \
  --task-definition "$CURR_TASK_DEF_ARN")

# Get family from current task definition
TASK_DEF_FAMILY=$(echo "$CURR_TASK_DEF_JSON" | jq -r '.taskDefinition.family')

echo "Generating a new task definition JSON..."
echo "$CURR_TASK_DEF_JSON" \
  | jq -r '.taskDefinition' \
  | jq -r '{ "family", "containerDefinitions", "volumes", "placementConstraints"}' \
  | jq -r '.containerDefinitions[0].image='\""${IMAGE}":"${TAG}"\" > ./task_definition.json

echo "Creating a new revision of task definition..."
NEW_TASK_DEF=$(aws ecs register-task-definition \
  --region "${AWS_REGION}" \
  --cli-input-json file://task_definition.json \
  | jq -r '.taskDefinition' \
  | jq -r '{ "taskDefinitionArn", "revision" }')

# Populate variables
NEW_TASK_DEF_ARN=$(echo "$NEW_TASK_DEF" | jq -r '.taskDefinitionArn')
NEW_TASK_DEF_REV=$(echo "$NEW_TASK_DEF" | jq -r '.revision')

echo "Updating service with new revision of task definition..."
UPDATED_SERVICE=$(aws ecs update-service \
  --region "${AWS_REGION}" \
  --cluster "${CLUSTER}" \
  --service "${SERVICE}" \
  --task-definition "${TASK_DEF_FAMILY}":"${NEW_TASK_DEF_REV}")

echo "Deployments:"
echo "$UPDATED_SERVICE" | jq -r ".service.deployments"

# Checking deployment status
for ATTEMPT in {1..20}; do
  DEPLOYMENT_COMPLETE=$(aws ecs describe-services \
    --region "${AWS_REGION}" \
    --services "${SERVICE}" \
    --cluster "${CLUSTER}" \
    | jq -r --arg arn "${NEW_TASK_DEF_ARN}" '.services[0].deployments
    | .[]| select(.taskDefinition == $arn)
    | (.desiredCount == .runningCount and .status == "PRIMARY")')

  echo "Checking deployment status..."
  echo "Complete: $DEPLOYMENT_COMPLETE"

  if [ "$DEPLOYMENT_COMPLETE" == "true" ]; then
    break
  elif [[ "$ATTEMPT" -ne "20" && "$DEPLOYMENT_COMPLETE" == "false" ]]; then
    echo "Sleeping..."
    sleep 30
    continue
  else
    echo "Deployment failed."
    exit 1
  fi
done