AWS XRay Tracing - Not Displaying Trace Map or SubSegments - amazon-web-services

Question

I am trying to trace a serverless express Lambda function using AWSXRay.
I have tried several different approaches to this and nothing seems to work.
If I leave out the aws-xray-sdk-express middleware, I will see all my segments in the Timeline, and see my Lambda function appearing twice in the Trace Map. If I include the express middleware, I will see the middleware segment ('Super Dooper Trace Function') in the Trace Map and just the first subsegment ('MyFirstTrace') in the Timeline (not in the Trace Map).
I am trying to get all Subsegments to appear in both the Timelines and Node Graphs
const AWSXray = require('aws-xray-sdk');
const xrayExpress = require('aws-xray-sdk-express');
const express = require('express');
const awsServerlessExpress = require('aws-serverless-express');
module.exports.handler = async (event, context) => {
const app = express();
app.use(xrayExpress.openSegment('Super Dooper Trace Function'));
app.get('/test', async (req, res) => {
const result = await doWork();
res.send(result);
});
app.use(xrayExpress.closeSegment());
const server = awsServerlessExpress.createServer(app);
return awsServerlessExpress.proxy(server, event, context, 'PROMISE').promise;
}
const doWork = async () => {
const res1 = await traceMyFunction('MyFirstTrace', 3000)
const res2 = await traceMyFunction('MySecondTrace', 3000);
const res3 = await traceMyFunction('MyThirdTrace', 2000);
return [res1, res2, res3];
}
const traceMyFunction = (name, delayMs) => {
return trace(name, async () => {
return delay(delayMs)
});
}
function trace(name, promiseFunction) {
return new Promise((resolve, reject) => {
AWSXray.captureAsyncFunc(name, (subSegment) => {
promiseFunction(subSegment)
.then((result) => {
resolve(result);
subSegment.close();
}).catch((e) => {
subSegment.close();
reject(e)
});
});
});
}
const delay = (ms) => {
return new Promise((res, rej) => {
setTimeout(() => res({ time: ms }), ms)
});
};
This is the resultant XRay Trace
And this is the Trace Raw Data
{
"Duration": 8.278,
"Id": "1-5e2f6cc3-a99e6c08f02ce0aec7ab7121",
"Segments": [
{
"Document": {
"id": "87ca46b60ded68e1",
"name": "Super Dooper Trace Function",
"start_time": 1580166338.92,
"end_time": 1580166347.198,
"http": {
"request": {
"url": "http://localhost/test",
"method": "GET",
"user_agent": "",
"client_ip": ""
},
"response": {
"status": 200
}
},
"aws": {
"xray": {
"sdk": "X-Ray for Node.js",
"sdk_version": "2.5.0",
"package": "aws-xray-sdk"
}
},
"service": {
"version": "unknown",
"runtime": "node",
"runtime_version": "v12.13.0",
"name": "unknown"
},
"trace_id": "1-5e2f6cc3-a99e6c08f02ce0aec7ab7121",
"subsegments": [
{
"id": "98e9f32273700e6e",
"name": "MyFirstTrace",
"start_time": 1580166339.078,
"end_time": 1580166342.082
}
]
},
"Id": "87ca46b60ded68e1"
}
]
}

Answer 1

Serverless Express has known incompatabilities with the current X-Ray SDK - due to the fact Lambda generates its own Segment, then the Express middleware tries to create one as well. We're planning to address this in the near future.
https://github.com/aws/aws-xray-sdk-node/issues/45
For the full explanation, see this thread: https://github.com/aws/aws-xray-sdk-node/issues/30