[Playground] OTLP-Mapper - instana to otlp span mapper by abhilash-sivan · Pull Request #2534 · instana/nodejs

abhilash-sivan · 2026-05-04T17:37:09Z

UI: https://instana.io/s/B2R0pfHbSpaV5jXmQNDd7w

This is just a playground where we convert Instana spans to Otel spans and send them to the Otel backend.

INSTANA_OTLP_FORMAT=true SERVICE_NAME=test-nodejs-service INSTANA_DEBUG=true node index.js

finalize architecture
test: send traces via otlp port and metrics via standard port - Idenfies 2 diff apps 1. Otel and 2. Node.js. We have to add metrics mapping. Discussed/Agreed with community.
figure out: node.http.server - what is the official otel name/value so that the backend is labeling everything correctly in the UI? (prio 1)

https://instana.io/s/Ehe2Zhb7QyKyxrmQg0fK8Q The BE uses path_tpl or url values ot show in the UI, so we mapped the otel span name to the same data from Instana span.

abhilash-sivan · 2026-05-07T14:30:51Z

+  // console.log(JSON.stringify(otlpFormat));

-  const payloadAsString = JSON.stringify(otlpFormat, circularReferenceRemover());
+  const payloadAsString = JSON.stringify(data, circularReferenceRemover());


Doing the conversion from spanBuffer

abhilash-sivan · 2026-05-07T14:32:10Z

+ * @param {import('../../core').InstanaBaseSpan} span
+ * @returns {import('../../core').InstanaBaseSpan} The transformed span.
+ */
+module.exports.transform = span => {


the same transform logic, like we already do for instana internal format to backend compatible conversion

abhilash-sivan · 2026-05-07T14:32:30Z

 'use strict';

-// Gespeicherte Resource-Informationen für Metrics (wenn kein "from" Feld vorhanden)
+const { getOtlpAttributeMappings } = require('./backend_mappers/otlpMapper');


moved the file to core

abhilash-sivan · 2026-05-07T14:34:10Z

+
+      const otlpKey = sectionMappings[field] || `${dataKey}.${field}`;
+
+      // Determine value type and format


This attribute addition is optional

abhilash-sivan · 2026-05-07T14:35:04Z

+  if (normalized.length > 32) {
+    return normalized.slice(-32);
+  }
+  return normalized.padStart(32, '0');


prepending with 0s due to the length mismatch for traceId.
We currently use 16, but otel uses 32

abhilash-sivan · 2026-05-07T14:36:53Z

  spans = [];
  batchingBuckets.clear();

+  const processedSpans =


This is where the conversion is happening.

This seems to be the optimal place because if we convert early, then in some places we talk Instana format and it could raise unexpected issues. So before transmission seems simple and maintanable

Should we do this here or just after the current BE transformation,
https://github.com/instana/nodejs/pull/2534/changes?utm_source=chatgpt.com#diff-462ace70d7ac6eb4cd6f82756059c88629bfad1463fde0498d89106d7ccc8104L193

Right now we’re applying the transformation after collecting all spans. IMO it would be cleaner to do it before calling transmitSpans, so the transmit layer only deals with already-transformed spans.

TBD

Yeah, I agree. This would be a more cleaner way

// Transform internal span data format into external (backend) readable format.
span = applySpanTransformation(span);

Just after this transformation, we can call the Otel transformation.

One thing we have to consider is that currently all the spans intended for transmission — i.e., the array of spans — are converted together. If we do it in the above-mentioned area, we will have to process the spans individually.

Note: TBD — Transform each span to OTLP format immediately in addSpan and store them in OTLP format in the buffer if batching is enabled. This would require changes to the batching logic.

How do you want to organize the agent ports etc?

OTLP mode is on -> port will change.
There is something missing.

Also:
How can we skip the agent announcement cycle when connecting to an otel collector later?
Did you draw that path as well to confirm the architecture?

No, I haven’t worked much on the architecture yet. I can work on the dynamic port connections part, and I’ll also think through the agent announcement cycle and how we can skip it when connecting to an OTel collector

kirrg001 · 2026-05-11T12:10:04Z

 const agentOpts = require('./agent/opts');
 const cmdline = require('./cmdline');
-const otlpTransformer = require('./otlpTransformer');
+const otlpTransformer = require('@instana/core/src/tracing/otlpTransformer');


Could you please reset the file? I think no changes needed as part of this playground, right?

Yeah, no major changes here. Only the relevant change is removing the Otel span transforming logic from this file

kirrg001 · 2026-05-11T12:10:47Z

-    };
+    return createSafeTransform(mapper.transform);
+  },
+  get otlpTransform() {


This is not a backend mapper.
Could you please move this unit to an otlp mapper folder?
The folder will have multiple files later.

Yeah got it

kirrg001 · 2026-05-12T08:21:12Z

+  },
+
+  // resource but added for ui view, without this .. ?
+  service: {


I don't think this is right? Service is part of resource attrs?

Yeah, it is a resource; I will remove this. I wonder how the UI mappings will change because this is shown in the UI under the calls section:

Maybe this will be inherited from env var, I will check and update accordingly

kirrg001 · 2026-05-12T09:05:34Z

test: send traces via otlp port and metrics via standard port - Idenfies 2 diff apps 1. Otel and 2. Node.js

This needs to be communicated in the next WG. Traces & Metrics mapping is required.

abhilash-sivan force-pushed the chore-otel-span-mapper branch from 4490ab0 to f1c0d6f Compare May 4, 2026 18:07

abhilash-sivan changed the base branch from main to chore-otlp-playground May 7, 2026 06:42

abhilash-sivan added 3 commits May 7, 2026 18:08

chore: phase 1

378f117

chore: phase 2

c1ef77d

chore: phase 3

d261bc5

abhilash-sivan force-pushed the chore-otel-span-mapper branch from 53e1fcc to d261bc5 Compare May 7, 2026 12:45

abhilash-sivan added 5 commits May 7, 2026 18:20

chore: cleanup

17710d0

chore: rewrite

0a6ec17

chore: test

8a89eef

chore: a

c78331c

chore: new fields

bcb034e

abhilash-sivan commented May 7, 2026

View reviewed changes

chore: test

980a1c0

abhilash-sivan changed the title ~~Chore otel span mapper~~ chore: instana-otlp span mapper May 7, 2026

abhilash-sivan changed the title ~~chore: instana-otlp span mapper~~ [Playground] OTLP-Mapper - instana to otlp span mapper May 8, 2026

abhilash-sivan added 2 commits May 10, 2026 17:17

test: fixed failing test

5aebc15

chore: cleanup

8c6cc88

kirrg001 reviewed May 11, 2026

View reviewed changes

kirrg001 reviewed May 12, 2026

View reviewed changes

chore: ui corrected

c3179eb


		const otlpKey = sectionMappings[field] \|\| `${dataKey}.${field}`;

		// Determine value type and format

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abhilash-sivan commented May 4, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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kirrg001 commented May 12, 2026

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abhilash-sivan commented May 4, 2026 •

edited

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