backstage: 🐛 Bug Report: Opentelemetry setup is not working properly when javascript is bundled.

📜 Description

The Backstage opentelemetry tutorial works in development but when the backend gets bundled it messes up the order of the code causing certain instrumentations to not be applied

👍 Expected behavior

All instrumentations from the getNodeAutoInstrumentations() metapackage should be applied after building the backend.

👎 Actual Behavior with Screenshots

Only certain instrumentations get applied, causing metrics to not be tracked.

Bellow is the bundled code which shows how the imports are being grouped together making the code for the instrumentation get pushed under all of the other imports. This is what is breaking the instrumentations. Per the documentation, the code for the sdk initialization needs to be at the top before all other imports.

'use strict';

var autoInstrumentationsNode = require('@opentelemetry/auto-instrumentations-node');
-----
other imports
-----

function _interopDefaultLegacy (e) { return e && typeof e === 'object' && 'default' in e ? e : { 'default': e }; }

function _interopNamespace(e) {
    if (e && e.__esModule) return e;
    var n = Object.create(null);
    if (e) {
        Object.keys(e).forEach(function (k) {
            if (k !== 'default') {
                var d = Object.getOwnPropertyDescriptor(e, k);
                Object.defineProperty(n, k, d.get ? d : {
                    enumerable: true,
                    get: function () { return e[k]; }
                });
            }
        });
    }
    n["default"] = e;
    return Object.freeze(n);
}

var Router__default = /*#__PURE__*/_interopDefaultLegacy(Router);
var Docker__default = /*#__PURE__*/_interopDefaultLegacy(Docker);
var esb__default = /*#__PURE__*/_interopDefaultLegacy(esb);
var winston__namespace = /*#__PURE__*/_interopNamespace(winston);
var fetch__default = /*#__PURE__*/_interopDefaultLegacy(fetch);

const sdk = new sdkNode.NodeSDK({
  metricReader: new exporterPrometheus.PrometheusExporter({}, () => {
    console.log(
      `OpenTelemetry prometheus scrape endpoint: http://localhost:${exporterPrometheus.PrometheusExporter.DEFAULT_OPTIONS.port}${exporterPrometheus.PrometheusExporter.DEFAULT_OPTIONS.endpoint}`
    );
  }),
  instrumentations: [autoInstrumentationsNode.getNodeAutoInstrumentations()]
});
sdk.start();

👟 Reproduction steps

1. Follow tutorial shown here. You might need to switch from console metrics exporter to something else, like prometheus, since the default one will spam a lot of logs https://backstage.io/docs/tutorials/setup-opentelemetry
2. Add OTEL_LOG_LEVEL=DEBUG environment variable
3. Start application in development mode and observe different instrumentations being applied. One of them is @opentelemetry/instrumentation-http
4. Build your application and create a container from the built image.
5. Add OTEL_LOG_LEVEL=DEBUG environment variable and start looking
6. Observe that the @opentelemetry/instrumentation-http instrumentation and lots of other ones are not being applied.
7. You can also check your bundled backend inside app/packages/backend/dist/*.cjs.js file which will confirm the problem with the order

📃 Provide the context for the Bug.

I played around with this a bit and I couldn’t find a solution. The fix would be to somehow inject the instrumentation code at the beginning of the bundled backend application. This is something I have tested by directly editing the bundled backend by setting the configuration at the beginning and restarting the application. After that the instrumentations get applied correctly. There is also an option to copy the instrumentation.ts file inside the Dockerfile to have it there after everything gets build. With this we can than run the node application by specifying the --require option with the path to the instrumentation. I have not managed to get this working, but it could be possible

🖥️ Your Environment

No response

👀 Have you spent some time to check if this bug has been raised before?

• I checked and didn’t find similar issue

🏢 Have you read the Code of Conduct?

• I have read the Code of Conduct

Are you willing to submit PR?

No, but I’m happy to collaborate on a PR with someone else