Remove AWS ECS Task Definitions in bulk

clear-task-definitions.sh

#!/usr/bin/env bash

set -o errexit
set -o nounset
set -o pipefail

FAMILY_PREFIX=""

# Ensure variables are set, that we don't directly use. This works do to the nounset option.
[[ "${AWS_PROFILE:?}" ]]

declare -x AWS_PAGER=""

if [[ "${TRACE-0}" == "1" ]]; then
	set -o xtrace
fi

join_by() {
  local d=${1-} f=${2-}
  if shift 2; then
    printf %s "$f" "${@/#/$d}"
  fi
}

deregister_active() {
  mapfile  -t TASK_DEFINITIONS < <(aws ecs list-task-definitions --status "ACTIVE" --family-prefix ${FAMILY_PREFIX} --query "taskDefinitionArns[]" --output json | jq -r '.[]')

  echo "Total active: ${#TASK_DEFINITIONS[@]}"

  for DEF in "${TASK_DEFINITIONS[@]}"; do
    aws ecs deregister-task-definition --task-definition "${DEF}" --query 'taskDefinition.[taskDefinitionArn, status]' --output text
    sleep 0.2
  done
}

delete_inactive() {
  mapfile  -t TASK_DEFINITIONS < <(aws ecs list-task-definitions --status "INACTIVE" --family-prefix ${FAMILY_PREFIX} --query "taskDefinitionArns[]" --output json | jq -r '.[]')

  GROUP=10
  echo "Total inactive: ${#TASK_DEFINITIONS[@]}"
  for ((i=0; i < ${#TASK_DEFINITIONS[@]}; i+=GROUP)); do
    part=( "${TASK_DEFINITIONS[@]:i:GROUP}" )

    DEF_STRING=$(join_by ' ' "${part[@]##*/}")
    echo "Deleting '${DEF_STRING}'"
    aws ecs delete-task-definitions --task-definitions ${DEF_STRING} --query 'taskDefinitions[].[taskDefinitionArn, status]' --output text
    if [ "$i" -lt "${#TASK_DEFINITIONS[@]}" ]; then
      sleep 0.5
    fi
  done
}
FAMILIES=(example-to-delete another-to-delete)

main() {
  for fam in "${FAMILIES[@]}"; do
    echo
    echo "Family: ${fam}"
    FAMILY_PREFIX=${fam}
    deregister_active
    echo 
    delete_inactive
    sleep 2
  done
}

cd "$(dirname "$0")"
main "$@"