#!/bin/bash

# Usage: $0 {days} [--delete]
# Script searches for images pushed to ECR older than specified (default is 30 days)
# Checks if image is not running in any ECS container and then prints deletion command
# or deletes it directly.
#
# Script needs working AWSCLI config (`aws configure`) to function

DAYS=${1:-"30"}
THRESHOLD=$(date -d "$DAYS days ago" +%s)
RUNNING=`mktemp` || exit 1

echo --------------
echo Searching for running containers
aws ecs list-clusters | while read clsTag clsArn; do
	echo Found cluster $clsArn
	aws ecs list-tasks --cluster "$clsArn" --desired-status RUNNING --output text | while read tskTag tskArns; do
		echo Found taskArn $tskArns
		aws ecs describe-tasks --cluster "$clsArn" --tasks "$tskArns" --output text | while read -a tskInfo; do
			if [[ ${tskInfo[0]} == "TASKS" ]]; then
				tskDefArn=${tskInfo[9]};
				echo "Found TaskDefinitionArn $tskDefArn"
				aws ecs describe-task-definition --task-definition "$tskDefArn" | while read -a tskDefInfo; do
					if [[ ${tskDefInfo[0]} == "CONTAINERDEFINITIONS" ]]; then
						imgTag=${tskDefInfo[3]}
						echo -n "Found tagged image $imgTag"
						IFS='/:' read repoUri repoName imgTag <<< "$imgTag"
						echo " Repository:$repoName Tag:$imgTag"
						aws ecr describe-images --repository-name $repoName --image-ids "imageTag=$imgTag" | while read imgTag imgDigest _; do
							if [[ $imgTag == "IMAGEDETAILS" ]]; then
								echo Image digest: $imgDigest;
								echo $imgDigest >> $RUNNING;
							fi
						done
					fi
				done
			fi
		done
	done
done

echo --------------
echo Searching images older than `date -d "$DAYS days ago"` \($THRESHOLD\)

aws ecr describe-repositories --output text | while read repoTag repoCreated registryId repoArn repoName repoUri ; do
	echo Found repository $repoName
	aws ecr describe-images --repository-name $repoName --output text | while read imgTag imgDigest imgCreated imgSize ; do
		if [[ $imgTag = 'IMAGEDETAILS' && ($imgCreated < $THRESHOLD) ]]; then
			echo -n Found image $imgDigest
			if grep -q $imgDigest $RUNNING; then
				echo "...image is running. Skipped."
			else
				if [[ $2 == "--delete" ]]; then
					echo "...deleting!"
					aws ecr batch-delete-image --repository-name $repoName --image-ids "imageDigest=$imgDigest"
				else
					echo "...should be deleted."
					echo aws ecr batch-delete-image --repository-name $repoName --image-ids "imageDigest=$imgDigest"
				fi
			fi
		fi
	done
done

rm -f $RUNNING