fclone.sh - rclone wrapper with extra functionality

fclone.sh

#!/bin/bash
# fclone.sh v0.4.0
#
# Wrapper around rclone with extra functionality:
#
# - Flag `--drive-service-account-file-path` to take a random service account file from that folder
# - Flag `--drive-service-account-file-path` can also take a URL for a service account credentials.
# - `remote:{ID}` syntax to use the folder with that ID in the remote, instead of full path.
#
# Usage:
# ./fclone.sh --drive-service-account-file-path=accounts copy source:{ID-1} target:{ID-2}
# ./fclone.sh --drive-service-account-file-path="https://example.com/accounts/today.json" copy source:{ID-1} target:{ID-2}

fclone() {
  local service_account_file=""
  local service_account_file_path=""
  local service_account_credentials=""

  local args

  while (($#)); do
    case "$1" in
      # `--drive-service-account-file-path path`
      --drive-service-account-file-path)
        if [ "$2" ]; then
          service_account_file_path="$2"
          shift
        fi
        ;;
      # `--drive-service-account-file-path=path`
      --drive-service-account-file-path=?*)
        service_account_file_path="${1#*=}" # Delete everything up to "=" and assign the remainder.
        ;;
      # Empty `--drive-service-account-file-path=`
      --drive-service-account-file-path=)
        ;;
      # End of all options convention.
      --)
        shift
        break
        ;;
      # Remote in format remote:{folder-id}
      *:{*})
        name="${1%:*}"
        NAME=$(echo ${name/-/_} | tr '[:lower:]' '[:upper:]')
        root_folder_id="${1#*:}"
        # Removes open curly bracket
        root_folder_id=${root_folder_id#*{}
        # Removes closing curly bracket
        root_folder_id=${root_folder_id%\}}
        export "RCLONE_CONFIG_${NAME}_ROOT_FOLDER_ID"=$root_folder_id
        args+=("${name}:")
        ;;
      # Default case: store into the args.
      *)
        args+=("$1")
        ;;
    esac

    shift
  done

  # Figures out a SA to use.
  if [ -n "${service_account_file_path}" ]; then
    case "${service_account_file_path}" in
      # If a URL, gets the SA from it into credentials JSON.
      http*)
        service_account_credentials=$(curl -s "${service_account_file_path}")
        args+=("--drive-service-account-credentials=${service_account_credentials}")
        ;;
      # Otherwise a file, picks a random SA that has not been used today.
      *)
        service_account_file=$(find "${service_account_file_path}"/*.json -mtime +1 | sort -R | tail -1)
        args+=("--drive-service-account-file=${service_account_file}")
        ;;
    esac
  fi

  OPTARR=("${args[@]}")
  set -- "${OPTARR[@]}"

  # Removes the first element from `$@` if it is an empty string.
  [ -z "$1" ] && shift
  rclone "$@"

  # Update the modified time on the service account file so it won't be reused today.
  if [ -n "${service_account_file}" ]; then
    touch "${service_account_file}"
  fi
}

fclone "$@"