autoscale-do-block-storage/checkvolumesize

#!/usr/bin/env bash

# Parse options
POSITIONAL=()
while [[ $# -gt 0 ]]; do
  key="$1"

  BUFFER=10
  LOG=false

  case $key in
      --token)
        TOKEN="$2"
        shift
        shift
        ;;

      --device)
        DEVICE="$2"
        shift
        shift
        ;;

      --volume-name)
        VOLUME_NAME="$2"
        shift
        shift
        ;;

      --volume-region)
        VOLUME_REGION="$2"
        shift
        shift
        ;;

      --buffer)
        BUFFER="$2"
        shift
        shift
        ;;

      --log)
        LOG=true
        shift
        shift
        ;;

      *)
      POSITIONAL+=("$1")
        shift
        ;;
  esac
done
set -- "${POSITIONAL[@]}"

log () {
  prefix=""
  if [[ "$LOG" = true ]]; then
    prefix="$(date "+%Y-%m-%d %H:%M:%S") "
  fi
  echo $prefix$@
}

check_root () {
  if [[ $UID != 0 ]]; then
    log "This script must be run as root"
    exit 1
  fi
}

digital_ocean_api () {
  endpoint=$1
  post_data=$2

  method="GET"
  if [[ $post_data ]]; then
    method="POST"
  fi

  args=()
  args+=("--silent")
  args+=("-X" $method)
  args+=("-H" "Content-Type: application/json")
  args+=("-H" "Authorization: Bearer ${TOKEN}")
  if [[ $post_data ]]; then
    args+=("-d" $post_data)
  fi
  args+=("https://api.digitalocean.com/v2/${endpoint}")

  curl "${args[@]}"
}

bytes_to_gigabytes () {
  bytes=$1

  expr $bytes / 1024 / 1024
}

check_device_free_space () {
  device=$1

  bytes_free=$(df --output=avail $device | tail -n 1)
  bytes_to_gigabytes $bytes_free
}

main () {
  check_root

  # TODO: Check dependencies

  # TODO: Check required options are set

  # Check available volume space
  log "Checking available space on device \"${DEVICE}\" is above ${BUFFER}GB requirement..."
  volume_free_space=$(check_device_free_space $DEVICE)
  if [[ $volume_free_space -gt $BUFFER ]]; then
    log "${volume_free_space}GB available, all good!"
    return
  fi
  log "Only ${volume_free_space}GB available, volume resize required"

  # Get volume data
  log "Getting data for volume \"${VOLUME_NAME}\" in region \"${VOLUME_REGION}\"..."
  volume_json=$(digital_ocean_api "volumes?region=${VOLUME_REGION}" | jq -r --arg VOLUME_NAME "${VOLUME_NAME}" '.volumes | .[] | select(.name==$VOLUME_NAME)')
  volume_id=$(echo $volume_json | jq -r .id)
  volume_size=$(echo $volume_json | jq -r .size_gigabytes)
  log "Volume ID is \"${volume_id}\" and is currently ${volume_size}GB"

  # Increase volume size
  new_volume_size=$(expr $volume_size + $BUFFER)
  log "Increasing volume size to ${new_volume_size}GB..."
  action_json=$(digital_ocean_api "volumes/2cbebc6a-ff42-11e9-a238-0a58ac14a19d/actions" '{"type":"resize","size_gigabytes":'$new_volume_size'}')
  action_id=$(echo $action_json | jq -r '.action.id')
  log "Created action \"${action_id}\""

  # Wait for volume resize
  log "Waiting for action to complete..."
  while true; do
    resize_status=$(digital_ocean_api "actions/$action_id" | jq -r '.action.status')
    if [[ "${resize_status}" == "completed" ]]; then
      break
    fi
    sleep 1
  done
  log "Volume resize complete!"

  # Resize filesystem
  log "Resizing filesystem..."
  sudo resize2fs $device 2>&1 | while read line; do
    if [[ "${line}" != "" ]]; then
      log $line
    fi
  done
  log "Filesystem resize complete!"

  # Show new available space on completion
  new_free_space=$(check_device_free_space $DEVICE)
  log "Device \"${DEVICE}\" now has ${new_free_space}GB available"
}

main