xray middleware for micro fails with Error: Failed to get the current sub/segment from the context

[styfle]

I created a repository so you can reproduce the issue here:

https://github.com/styfle/aws-xray-bug

Related to #60

/cc @chrisradek

[chrisradek]

@styfle
Are you seeing this issue everytime you attempt to trace your micro app? One thing I noticed is your package.json uses [email protected], but for async support, you'd want to be using [email protected]

When I ran your example with this change, I was able to see multiple traces when calling the endpoint with GET.

[styfle]

@chrisradek Thanks for the response!

I ended up changing the code to use [email protected] but I still needed to access private APIs to get it to log HTTP Request and HTTP Response.

Here's what I ended up with.

const AWSXRay = require('aws-xray-sdk');
const { IncomingRequestData } = AWSXRay.middleware;
console.log('Patching http global');
AWSXRay.captureHTTPsGlobal(require('http'));

function trace(handler) => {
	console.log('start tracing micro');
	return async function traceAsync(req, res) {
		const namespace = AWSXRay.getNamespace();
		const segment = new AWSXRay.Segment('some-segment-name-here');
		segment.http = new IncomingRequestData(req);

		res.on('finish', function finish() {
			console.log('end tracing micro');
			segment.http.close(res);
			segment.http.status = res.statusCode || '';
			if (res.statusCode === 429) {
				segment.throttle = true;
			}
			if (res.headers && res.headers['content-length']) {
				segment.http['content_length'] = res.headers['content-length'];
			}
			segment.close();
		});

		namespace.bindEmitter(req);
		namespace.bindEmitter(res);
		const result = await namespace.runAndReturn(async function run() {
			AWSXRay.setSegment(segment);
			const handlerResponse = await handler(req, res);
			segment.close();
			return handlerResponse;
		});
		return result;
	};
}

function captureAsync(func, args) {
	const { name = 'anonymous' } = func;
	console.log('captureAsync ', name);
	return new Promise((resolve, reject) => {
		AWSXRay.captureAsyncFunc(name, async (subsegment) => {
			try {
				const p = func.apply(this, args);
				let result;
				if (p instanceof Promise) {
					result = await p;
				} else {
					result = p;
				}
				subsegment.close();
				resolve(result);
			} catch (error) {
				subsegment.close(error);
				reject(error);
			}
		});
	});
}

module.exports = { trace, captureAsync };

Even with these private APIs, I still sometimes does not log the HTTP Response 🤷‍♂️

[styfle]

@chrisradek I think I found another bug.

I can't seem to use an annotation key that contains a hyphen.

For example segment.addAnnotation('x-now-id', 'abc123') does not work but segment.addAnnotation('xNowId', 'abc123') works as expected.

Is this a known limitation or a bug?

[chrisradek]

@styfle
Annotation keys can be up to 500 alphanumeric characters. No spaces or symbols except underscores. Values can be up to 1000 unicode characters.

[styfle]

I see now.

It was silently dropping that data even with the following flags:

- AWS_XRAY_DEBUG_MODE=TRUE
- AWS_XRAY_CONTEXT_MISSING=LOG_ERROR

I would expect to see some sort of logging error when a segment does not meet this criteria.

[styfle]

For some strange reason, there is no response logged around 30% the time (even with my res.on('finish') hack above.

[styfle]

@chrisradek The experimental tag does not work with Node 11.

error [email protected]: The engine "node" is incompatible with this module. Expected version ">= 4.x <= 10.x". Got "11.10.0"

Is there a reason why the package.json specifies <= 10.x?

---

Update: Looks like it was fixed in #89

Can you publish a new experimental tag to npm?

[manchuck]

@styfle The reason for working on node <= 10.x is due to the lambda execution environment. Lambada currently executes node @ 8.10

[chrisradek]

Closing this since we started talking about multiple issues. If you are still encountering issues after installing the experimental tag of the SDK, please feel free to open a new issue.