Error message when using Bun as the engine

[lostbean]

What happened?

Steps to Reproduce

Follow the any basic example of using Phoenix but Bun as the engine.

Actual Result

The logs are send and received by the Phoenix service but an error message is logged in the client for every request.

Expected Result

Keep sending the logs but no error messages in the client side.

Additional Details

Switch the JS engine to Node.js makes the system work normally with any error message.

OpenTelemetry Setup Code

import { LangChainInstrumentation } from "@arizeai/openinference-instrumentation-langchain";
import { SEMRESATTRS_PROJECT_NAME } from "@arizeai/openinference-semantic-conventions";
import * as CallbackManagerModule from "@langchain/core/callbacks/manager";
import { diag, DiagConsoleLogger, DiagLogLevel } from "@opentelemetry/api";
import { OTLPTraceExporter } from "@opentelemetry/exporter-trace-otlp-proto";
import { Resource } from "@opentelemetry/resources";
// import { ConsoleSpanExporter } from "@opentelemetry/sdk-trace-base";
import {
  NodeTracerProvider,
  SimpleSpanProcessor,
} from "@opentelemetry/sdk-trace-node";
import { ATTR_SERVICE_NAME } from "@opentelemetry/semantic-conventions";

export function setupTracing() {
  // For troubleshooting, set the log level to DiagLogLevel.DEBUG
  diag.setLogger(new DiagConsoleLogger(), DiagLogLevel.INFO);

  const provider = new NodeTracerProvider({
    resource: new Resource({
      [ATTR_SERVICE_NAME]: "user-load-agent",
      [SEMRESATTRS_PROJECT_NAME]: "user-load-agent",
    }),
  });

  const otlpExporter = new OTLPTraceExporter({
    timeoutMillis: 50000,
  });

  // provider.addSpanProcessor(new SimpleSpanProcessor(new ConsoleSpanExporter()));
  provider.addSpanProcessor(new SimpleSpanProcessor(otlpExporter));

  const lcInstrumentation = new LangChainInstrumentation();
  // LangChain must be manually instrumented as it doesn't have a traditional module structure
  lcInstrumentation.manuallyInstrument(CallbackManagerModule);

  provider.register();

  // eslint-disable-next-line no-console
  console.log("👀 OpenInference initialized");

  return {
    forceFlush: async () => {
      otlpExporter.forceFlush();
      provider.forceFlush();
    },
  };
}

package.json

{
  "name": "myapp",
  "private": true,
  "version": "1.0.0",
  "type": "module",
  "module": "src/client.ts",
  "scripts": {
    "build": "tsc",
    "start": "bun run dist/client.js",
    "dev": "bun run --watch src/client.ts"
  },
  "engines": {
    "bun": "1.1.37"
  },
  "dependencies": {
    "@anthropic-ai/sdk": "^0.32.1",
    "@arizeai/openinference-instrumentation-langchain": "^0.2.0",
    "@opentelemetry/exporter-trace-otlp-http": "^0.49.1",
    "@opentelemetry/exporter-trace-otlp-proto": "^0.56.0",
    "@opentelemetry/sdk-trace-base": "^1.22.0",
    "@opentelemetry/sdk-trace-node": "^1.22.0",
    "dotenv": "^16.4.5",
    "express": "^4.21.1",
    "langchain": "^0.3.5",
    "typescript": "^5.6.3",
    "uuid": "^11.0.3",
    "ws": "^8.18.0"
  },
  "devDependencies": {
    "@types/bun": "latest",
    "@types/express": "^5.0.0",
    "@types/ws": "^8.5.13",
    "typescript": "^5.6.3"
  },
  "peerDependencies": {
    "prettier": "^3.3.3",
    "eslint": "^8"
  },
  "prettier": {}
}

Relevant log output

{"message":"Request timed out","originalLine":"59","originalColumn":"25","line":"87","column":"24","sourceURL":"/code/node_modules/@opentelemetry/exporter-trace-otlp-proto/node_modules/@opentelemetry/otlp-exporter-base/build/src/transport/http-transport-utils.js","stack":"Error: Request timed out\n    at <anonymous> (/code/node_modules/@opentelemetry/exporter-trace-otlp-proto/node_modules/@opentelemetry/otlp-exporter-base/build/src/transport/http-transport-utils.js:87:24)\n    at emit (node:events:183:48)\n    at emitCloseNT (node:http:191:21)\n    at <anonymous> (node:http:1074:18)\n    at <anonymous> (native:19:28)\n    at processTicksAndRejections (native:7:39)","name":"Error"}

Operating System and Version

macOS 15.1

Runtime and Version

bun 1.1.31, Node.js v20.17.0

[pichlermarc]

Hi @lostbean - thanks for reaching out.

Please note that bun is currently not supported by this project. If you can provide a fix that still passes the tests for Node.js we're happy to accept that fix.

[pichlermarc]

link to reproducer: https://github.com/pichlermarc/repro-5260
Two observations:

• the timeout happens immediately on export
• the export never arrives on the collector

@lostbean - in the issue you opened it says that "logs" arrive in Phoenix - are you trying to say that the trace export fails but you can see the traces that were exported? Or are you referring to something else? 🤔

[lostbean]

@pichlermarc what I meant is that all the messages are actually being delivered and registered in Phoenix (I can explore all the telemetry there). Even though it all seems to be working fine, I'm constantly getting the Request timed out messages logged in my terminal on every batch being send by opentelemetry.

[MarcRoemmelt]

I can confirm this in Bun 1.2.7

The error message is printed but logs, traces, and metrics are correctly exported.

[jahands]

Are we sure this is a bug in opentelemetry? Maybe Bun itself needs to fix it's behavior to be consistent with Node?

[pichlermarc]

Are we sure this is a bug in opentelemetry? Maybe Bun itself needs to fix it's behavior to be consistent with Node?

@jahands yes, it's also my assumption (I mentioned it here but forgot to add a comment on this issue).