I built a function in my NodeJS backend which has that purpose to retry for 10 times a request if a value on first request is equal to null. This behavior is need it because there is a worker function which uploads PDF to AWS, so the value I'm retrieving by the new function contains a PDF URL which very often on first request is null.

The goal is to check at first if we have the pdfUrl if that is not NULL so return the data.

If the pdfURLfor some reason is NULL then the function need to retry the request with a timeout of 20s and max 10 retries.

The function I tried is as follow and have several issues:

1. Seems is retrying 10 times either if the pdfUrl is not null instead of retrying only if it is null and only for max retries
2. The function after the 10 times should give back an error exception and not null
3. The function should give up and giving the error only if fails for 10 times

async function getIcfDocument(documentId, { log }) {
  log.info('Getting IcfDocument with last revision pdfUrl');
  const MAX_RETRIES = 10;
  const timeout = 20000;

  let data;
  for (let i = 0; i <= MAX_RETRIES; i += 1) {
    try {
      const { icfDocuments } = await request(
        CONSENT_SERVICE_URL,
        getICFDocumentRecipientsQuery,
        {
          documentId,
        }
      );

      if (icfDocuments.nodes[0].revision.pdfUrl) {
        log.info('Success the revision pdfUrl is present');
        data = icfDocuments;
      } else {
        log.debug(
          'Waiting to retrieve the last revision pdfUrl %s ms',
          timeout
        );
        await sleep(timeout);
        log.debug('Retrying times %s', i);
      }
    } catch (err) {
      log.error(
        'Failed to retrieve the data for document %s, Error: %s',
        documentId,
        err.message
      );
      return null;
    }
  }
  return data;
}

Will be nice to see a better way to what I have tried as I have some difficulties to make it so.

The request method above is requesting to a GQL query that why was implemented in this way

const { icfDocuments } = await request(
            CONSENT_SERVICE_URL,
            getICFDocumentRecipientsQuery,
            {
              documentId,
            }
          );

The icfDocuments is the resulting OBJ of the query which contains the urlPdfand other information. This query has to be retried if that url is null for max 10 times and 20s timeout between requests.

The query is this one as info

const getICFDocumentRecipientsQuery = gql`
  query GetICFDocumentRecipients($documentId: ID!) {
    icfDocuments(filter: { ids: [$documentId] }, pagination: { limit: 1 }) {
      nodes {
        id
        recipients {
          id
          email
          phone
          locale
        }
        revision {
          pdfUrl
        }
      }
    }
  }
`;