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    4. Using Queues to store data in R2

    Using Queues to store data in R2

    Example of how to use Queues to batch data and store it in an R2 bucket.

    The following Worker will catch JavaScript errors and send them to a Queue. The same Worker will receive those errors in batches and store them to a log file in an R2 bucket.

    wrangler.toml
    name = "my-worker"

    

    [[queues.producers]]
      queue = "my-queue"
      binding = "ERROR_QUEUE"

    

    [[queues.consumers]]
      queue = "my-queue"
      max_batch_size = 100
      max_batch_timeout = 30

    

    [[r2_buckets]]
      bucket_name = "my-bucket"
      binding = "ERROR_BUCKET"

    worker.ts
    type Environment = {
    	readonly ERROR_QUEUE: Queue;
    	readonly ERROR_BUCKET: R2Bucket;

    };

    

    export default {
      async fetch(req: Request, env: Environment): Promise<Response> {
        try {
          return doRequest(req);
        } catch (error) {
          await env.ERROR_QUEUE.send(error);
          return new Response(error.message, { status: 500 });
        }
      },
      async queue(batch: MessageBatch<Error>, env: Environment): Promise<void> {
        let file = '';
        for (const message of batch.messages) {
          const error = message.body;
          file += error.stack || error.message || String(error);
          file += '\r\n';
        }
        await env.ERROR_BUCKET.put(`errors/${Date.now()}.log`, file);
      },

    };

    

    function doRequest(request: Request): Promise<Response> {
      if (Math.random() > 0.5) {
        return new Response('Success!');
      }
      throw new Error('Failed!');

    }