abort: true raises errors when AWS SQS is polling for messages

[rhyek]

Background

looking at #389 i have the same problems. the issue i'm having is with the described behavior, my application can't handle SIGTERM signals properly/in a timely manner (hot reload, container cycling during k8s rolling updates). using abort = true is apparently crashing my app, and there's no clear way how to handle the thrown exception correctly.

if it helps the library maintainer or anyone else, this is what i'm using currently instead:

export type Consumer = {
  start: () => void;
  stop: () => void;
};

type ConsumerOptions = {
  queueUrl: string;
  batchSize?: number;
  handleMessage: (message: Message) => void | Promise<void>;
};

export function createConsumer(options: ConsumerOptions): Consumer {
  const { handleMessage, ...input } = options;
  const client = new SQSClient();
  const command = new ReceiveMessageCommand({
    MaxNumberOfMessages: options.batchSize ?? 10,
    // https://docs.aws.amazon.com/AWSSimpleQueueService/latest/SQSDeveloperGuide/sqs-short-and-long-polling.html#sqs-long-polling
    WaitTimeSeconds: 20,
    QueueUrl: options.queueUrl,
  });
  const abortController = new AbortController();
  return {
    start: async () => {
      while (!abortController.signal.aborted) {
        let result: ReceiveMessageCommandOutput;
        try {
          result = await client.send(command, { abortSignal: abortController.signal });
        } catch (error) {
          if (error.name === 'AbortError') {
            continue;
          } else {
            throw error;
          }
        }
        if (result.Messages) {
          await Promise.all(
            result.Messages.map(async (message) => {
              try {
                await handleMessage(message);
                if (message.ReceiptHandle) {
                  await client.send(
                    new DeleteMessageCommand({
                      QueueUrl: input.queueUrl,
                      ReceiptHandle: message.ReceiptHandle,
                    })
                  );
                }
              } catch (error) {
                console.error(error);
              }
            })
          );
        }
      }
    },
    stop: () => {
      abortController.abort();
    },
  };
}

Objectives

1. handle abort signal correctly

[MarcRoemmelt]

Leaving a comment here for other people running into this issue:

The EventEmitter class in NodeJS handles the error event, in case no handler is subscribed, by throwing the error (see https://nodejs.org/api/events.html#error-events).

The solution for the issue is therefore subscribing to the error event via consumer.on('error') and handling AbortErrorwhile, e.g. throwing everything else.