Troubleshooting Phoenix OTEL Integration for Flask Demo

Glen · 2025-05-29T19:07:19.504Z

Hi everyone. I'm trying to test Phoenix OTEL for a project demo. I'm currently using the following code: from phoenix.otel import register from app.config import Config # Register OpenTelemetry for Flask tracer_provider = register( project_name="agent_commercial", # Default is 'default' auto_instrument=True, # See 'Trace all calls made to a library' below endpoint=Config.PHOENIX_COLLECTOR_ENDPOINT, ) tracer = tracer_provider.get_tracer(__name__) However, I don't see the project appearing in the Phoenix UI. Is there something I might be missing? For context: It's a Flask app running locally, and I'm exposing it using ngrok for now.

Troubleshooting Phoenix OTEL Integration for Flask Demo | Arize AI Community

RunLLM
APP
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If your project is not appearing in the Phoenix UI, the most common causes are: (1) the endpoint is not set correctly, (2) the Phoenix server is not running or not accessible, (3) the project name is not being picked up, or (4) instrumentation is not initialized before your app code runs. According to the Phoenix OTEL setup docs, the endpoint should be the full OTLP HTTP endpoint (e.g., http://localhost:6006/v1/traces for local, or your ngrok URL with /v1/traces appended if using ngrok). Also, ensure that register() is called before any code that should be traced.If you are using authentication, set the PHOENIX_API_KEY or PHOENIX_CLIENT_HEADERS environment variable as described in Phoenix Authentication. Finally, confirm that your traces are being sent by checking Phoenix server logs and that your Flask app is instrumented before any requests are handled. If the project name is not set in the UI, double-check that the project_name argument is passed to register() as shown in the docs.Would you like more detail or troubleshooting steps?Sources: - Phoenix OTEL Setup - Phoenix Authentication
💡 Hint: Mention RunLLM in the thread for followups.
Anthony P.
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Let me know if RunLLMs suggestions are not helpful for you and I can dig in further
Glen
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Thanks Tony, I’ve reviewed those suggestions, but everything looks correct in the parameters I’m using for the register function. Still not seeing the project in the Phoenix UI—any other ideas?
Anthony P.
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What LLM Sdk are you using / attempting to instrument?
Anthony P.
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the project only appears after a trace from a compatible instrumented SDK is sent
Glen
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langchain
Anthony P.
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Did you install openinference-instrumentation-langchain in your environment in addition to phoenix otel?
Glen
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No, I haven’t set up that library yet.
Anthony P.
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no worries, let me know if you can get the example here setup https://docs.arize.com/phoenix/integrations/frameworks/langchain/langchain-tracing and then we can compare with your setup
Glen
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I want the tracer like decorator llm or chain in the functions
Anthony P.
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do you mean something like this? https://docs.arize.com/phoenix/tracing/how-to-tracing/setup-tracing/instrument-python#using-decorators
Glen
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Yes
Anthony P.
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the decorators allow you to trace your own code, with the data you specify. the langchain auto instrumentor will trace langchain calls automatically. it is up to you how you'd like to compose these features together, or if you'd just like to use one or the other. what did you have in mind?
Anthony P.
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my suggestion would be to run through the langchain example, and then the decorator example, pointed to different projects in Phoenix, and then compare how the spans like
Anthony P.
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and then move forward with which you like better

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