aws xray not monitoring dynamo dax client in nodejs

Question

I recently started using dynamodb dax within my node lambda function, however with 'amazon-dax-client' framework, i cannot longer capture transparently with http requests made by the framework, like so;

const AWS = AWSXRay.captureAWS(require('aws-sdk'));
const dynamoDB = AWSXRay.captureAWSClient(new AWS.DynamoDB(defaults.db.config));

I know i could create an async capture. but i am wondering if there is a better way to do this, like in the previous way and if i someone managed to capture requests, made with dax-client in the same way as with the dynamo client from aws framework.

score 7 · Accepted Answer · answered Jul 30 '18 at 16:22

7

DAX doesn't currently support XRay, because DAX doesn't use the standard AWS SDK HTTP client (it doesn't use HTTP at all).

The team has received other requests for XRay support so it's certainly something we're considering.

answered Jul 30 '18 at 16:22

Jeff Hardy

7,632
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1

Thanks for your answer. What protocol does dax use then, if you don’t mind me asking? I was convinced that dax using elasticache under the hood. – RicardoDuarte Jul 30 '18 at 16:26
2

It's a custom protocol over regular TCP using CBOR for data encoding. It's intended to minimize both data on the wire and encoding/decoding costs. – Jeff Hardy Jul 31 '18 at 17:25
@JeffHardy Hi Jeff, has there been any progress in this space? – Matt Rowles Dec 03 '19 at 07:05
1

@MattRowles I'm no longer on the DAX team, so I'm not sure what's been done or planned. – Jeff Hardy Dec 04 '19 at 15:37
do anyone know about current status ? – NIKHIL C M Feb 25 '20 at 13:55
Atm DAX still does not have xray. – Townsheriff May 08 '22 at 09:28
Opened an issue: https://github.com/aws/aws-dax-go/issues/44 – Maria Ines Parnisari May 31 '23 at 17:05

score 0 · Answer 2 · answered May 08 '22 at 12:40

While there is no official support for XRAY from DAX team. I wrote a little snippet as a workaround.

const db = new Proxy(documentClient, {
    get: (target: any, prop: any) => {
      if (typeof target[prop] === "function") {
        return (...args: any) => {
          const segment = xray
            .getSegment()
            ?.addNewSubsegment(`DynamoDB::${prop}`);

          const request = target[prop](...args);

          const promise = request
            .promise()
            .then((response: any) => {
              segment?.close();
              return response;
            })
            .catch((err: any) => {
              segment?.close();
              return Promise.reject(err);
            });

          return {
            ...request,
            promise: () => promise,
          };
        };
      }

      return target[prop];
    },
  });

const response await = db.query(...).promise();

Tested in AWS Lambda under VPC private subnet and AWS XRAY service endpoint.

aws xray not monitoring dynamo dax client in nodejs

2 Answers2