SQS trigger script template

/**

 * General Trigger Preprocessor

 *

 * ⚠️ This function runs BEFORE the main function.

 *

 * It processes raw trigger data (e.g., MQTT, HTTP, SQS) before passing it to main().

 * Common tasks:

 * - Convert binary payloads to string/JSON

 * - Extract metadata

 * - Filter messages

 * - Add timestamps/context

 *

 * The returned object determines main() parameters:

 * - {a: 1, b: 2} → main(a, b)

 * - {msg} → main(msg)

 *

 * @param event - Trigger data (e.g., MQTT, HTTP, SQS)

 * @returns Processed data for main()

 */

export async function preprocessor(

  event: {

    kind: 'sqs',

    msg: string,

    queue_url: string,

    message_id?: string,

    receipt_handle?: string,

    attributes: Record<string, string>,

    message_attributes?: Record<string, {

      string_value?: string,

      data_type: string

    }>

  },

) {

  if (event.kind === 'sqs') {

    try {

      // We assume the message is a JSON value

      const data = JSON.parse(event.msg);

      return {

        msg: event.msg,

        data,

        message_attributes: event.message_attributes

      };

    } catch (error) {

      throw new Error("Failed to parse SQS message as JSON");

    }

  }

  throw new Error(`Expected SQS trigger kind, got: ${event.kind}`);

}

/**

 * Main Function - Handles processed trigger events

 *

 * ⚠️ Called AFTER preprocessor(), with its return values.

 *

 * @param msg - Raw message content

 * @param data - Parsed JSON data

 * @param message_attributes - User-defined attributes

 */

export async function main(

  msg: string,

  data: any,

  message_attributes?: Record<string, { string_value?: string; data_type: string }>

) {

  // Implement the main function logic here

}