[WIP] ECS register task definition script (update images with specific :tag)

script.sh

#!/usr/bin/env bash

export VERBOSE=false
export DRYRUN=false
export HELP=false
export AWS_REGION=
export AWS_PROFILE=
export AWS_DEBUG=

# declare -x DESIRED_COUNT=false

function usage() {
  cat <<EOM
usage: script.sh [options] <command> [parameters]

AVAILABLE COMMANDS
  script.sh register-task <family> [--tag tag]
EOM
  exit 3
}


function aws_ecs() {
  aws ecs --profile $AWS_PROFILE --region $AWS_REGION $AWS_DEBUG $@
}

function get_latest_task_definition() {
  declare TASK_DEF_ARNS=$(aws_ecs "list-task-definitions --family-prefix $1 --sort DESC")
  declare TASK_DEF_ARN=$(echo $TASK_DEF_ARNS | jq -r '.taskDefinitionArns[0]')

  aws_ecs "describe-task-definition --task-definition $TASK_DEF_ARN"
}

function replace_images_with_tag() {
  declare ORIGINAL=$(cat -)
  declare RESULT=$ORIGINAL
  declare TAG="$1"
  declare -a NAMES="${@:2}"

  for name in ${NAMES[@]}; do
    declare image=$(echo $ORIGINAL | jq -r ".[] | select(.name == \"$name\") .image")

    if [ "$image" == "" ]; then
      echo "Image \"$name\" not found in container definition"
      exit 201
    fi

    declare new_image=$(echo $image | sed -e "s/^\([^:]\+\)\(.*\)$/\1:$TAG/")
    RESULT=$(echo $RESULT | jq "(.[] | select(.name == \"$name\") | .image) |= \"$new_image\"")
  done

  echo $RESULT
}

function register_task_command() {
  declare -i ARGC=0
  declare -a ARGV=()

  declare -x TAG=latest

  while [[ $# -gt 0 ]]
  do
    case "$1" in
      --tag)
        TAG="$2"
        shift
        ;;
      *)
        ((++ARGC))
        ARGV=("${ARGV[@]}" "$1")
        ;;
    esac
    shift
  done

  if [ $ARGC -lt 2 -o $HELP == true ]; then
    usage
    exit 200
  fi

  declare FAMILY="${ARGV[0]}" && ARGV=("${ARGV[@]:1}")
  declare -a NAMES=${ARGV[@]}

  declare TASK_DEF=$(get_latest_task_definition $FAMILY)
  declare CONTAINER_DEF=$(echo "$TASK_DEF" | jq '.taskDefinition.containerDefinitions')
  declare NEW_CONTAINER_DEF=$(echo $CONTAINER_DEF | replace_images_with_tag $TAG $NAMES)

  if [ $DRYRUN == true ]; then
    echo $NEW_CONTAINER_DEF | jq '.'
    exit 0
  fi

  aws_ecs "register-task-definition --family $FAMILY --container-definitions $(echo $NEW_CONTAINER_DEF | jq -c '.')"
}

function deploy() {
  echo "deploying"

  while [[ $# -gt 0 ]]
  do
    case "$1" in
      -d|--desired-count)
        DESIRED_COUNT="$2"
        shift
        ;;
      *)
        ((++ARGC))
        ARGV=("${ARGV[@]}" "$1")
        ;;
    esac
    shift
  done

  echo ${ARGV[@]:0};
  echo $DESIRED_COUNT;
}

function revert() {
  echo "reverting"
  REVERT_COUNT=1

  while [[ $# -gt 0 ]]
  do
    case "$1" in
      --count)
        REVERT_COUNT="$2"
        shift
        ;;
      *)
        ((++ARGC))
        ARGV=("${ARGV[@]}" "$1")
        ;;
    esac
    shift
  done

  echo ${ARGV[@]:0};
  echo $DESIRED_COUNT;
}

function main() {
  declare -i ARGC=0
  declare -a ARGV=()
  declare COMMAND

  if [ $# -gt 0 ]; then
    COMMAND="$1" && shift
  fi

  case "$COMMAND" in
    register-task)
      register_task_command $@
      ;;
    deploy)
      deploy $@
      ;;
    revert)
      revert $@
      ;;
    test)
      test_command $@
      ;;
    *)
      usage
      exit 101
      ;;
  esac
}

if [ "$BASH_SOURCE" == "$0" ]; then
  declare -i ARGC=0
  declare -a ARGV=()

  set -o errexit
  set -o pipefail
  set -u
  set -e

  while [[ $# -gt 0 ]]
  do
    case "$1" in
      --profile)
        AWS_PROFILE="$2"
        shift
        ;;
      --region)
        AWS_REGION="$2"
        shift
        ;;
      --verbose)
        VERBOSE=true
        AWS_DEBUG="--debug"
        ;;
      --dry-run)
        DRYRUN=true
        ;;
      --help)
        HELP=true
        ;;
      *)
        ((++ARGC))
        ARGV=("${ARGV[@]}" "$1")
        ;;
    esac
    shift
  done

  if [ $VERBOSE == true ]; then
    set -x
  fi

  main ${ARGV[@]:0}

  exit 0
fi