leave-maintenance-mode.sh

#! /usr/bin/env bash

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

USAGE='leave-maintenance-mode.sh [--debug] [-h|--help] [--add-dyno-type type=count ...] [--confirm] [app_name ...]"

  leave maintenance mode for provided apps. Will also scale all web dynos for those apps to one.
  Passing --add-dyno-type will assume direct control over which dyno types to scale up and to what number.

  ================================== OPTIONS ==================================
  --debug                     Enables xtrace option, echoing all commands as
                              they are executed.
  --help|-h                   Display this message.
  --add-dyno-type type=count  Instead of scaling the web dyno to 1 (default) we
                              can pass this option to assume direct control
                              over what dyno types to up and to what number.
                              This flag can be passed repeatedly.
  --confirm                   automatically confirm entering maintenance mode'

APPS=()
DYNO_TYPE_CONFIGS=()
DYNO_TYPES_SPECIFIED=true
CONFIRM=false
while [[ "$#" -gt 0 ]]; do
    case $1 in
        --debug) set -o xtrace; shift ;;
        -h|--help) echo "$USAGE"; exit 0; shift ;;
        --add-dyno-type)
          shift
          if [[ "$1" == *"="* ]]; then
            DYNO_TYPE_CONFIGS+=($1)
          else
            echo "Error: --add-dyno-type must specify dyno type and scale target like this web=2"
            exit 1
          fi
          shift
          ;;
        --confirm) CONFIRM=true; shift ;;
        *) APPS+=($1); shift ;;
    esac
done

disable_maintenance() {
  app=${1:?'Must pass app to disable maintenace on'}
  echo "Waiting for ${app} to be available..."
  heroku ps:wait --app ${app}
  echo "Disabling maintenance mode of ${app}"
  heroku maintenance:off --app ${app}
}

declare -a DEFAULT_APPS=("arbeitnehmerverwaltung-prod" "arbeitsentgelt-production" "freigabe-production" "rechnungsstellung-production" "sv-einordnung-production")
if [ ${#APPS[@]} -eq 0 ]; then
  APPS=${DEFAULT_APPS[@]}
fi
if [ ${#DYNO_TYPE_CONFIGS[@]} -eq 0 ]; then
  DYNO_TYPES_SPECIFIED=false
fi

if ! ${CONFIRM}; then
  read -p "Leave maintenance mode for ${APPS[*]}? (y/n)" -n 1 -r
  >&2 echo
  if [[ $REPLY =~ ^[Nn]$ ]]; then
    exit 1
  fi
fi

for app in "${APPS[@]}"; do
  if ${DYNO_TYPES_SPECIFIED}; then
    for dyno_type_config in ${DYNO_TYPE_CONFIGS[@]}; do
      heroku ps:scale ${dyno_type_config} --app ${app}
    done
  else
    if [ -f ".heroku_dyno_scales_before_for_${app}" ]; then
      echo "Using existing .heroku_dyno_scales_before_for_${app} file for scaling dynos back up..."
      cat ".heroku_dyno_scales_before_for_${app}" | xargs -I{} heroku ps:scale {} --app ${app}
    else
      heroku ps:scale web=1 --app ${app}
    fi
  fi
  
  disable_maintenance ${app} &
done

# wait for subprocesses to finish
wait $(jobs -p)