Link a W&B run to trace function calls

Associate Weave traces with W&B runs for experiment tracking

With W&B Weave, you can trace function calls in your code and link them directly to the W&B runs in which they ran. When you trace a function with @weave.op() and call it inside a wandb.init() context, Weave automatically associates the trace with the W&B run. The Traces table shows links to any associated runs.

View a W&B run in the Traces table

Python

The following Python code shows how Weave links traced Ops to W&B runs when you run them inside a wandb.init() context. These traces appear in the Weave UI and are associated with the corresponding run.

To view a W&B run as a Weave trace:

1. In the terminal, install dependencies.

pip install wandb weave

2. Log in to W&B.

wandb login

3. In the following script, replace your-team-name/your-project-name with your W&B entity and project:

import wandb
import weave

def example_wandb(projname):
    # Split projname into entity and project
    entity, project = projname.split("/", 1)

    # Initialize Weave context for tracing
    weave.init(projname)

    # Define a traceable Op
    @weave.op()
    def say(message: str) -> str:
        return f"I said: {message}"

    # First W&B run
    with wandb.init(
        entity=entity,
        project=project,
        notes="Experiment 1",
        tags=["baseline", "paper1"],
    ) as run:
        say("Hello, world!")
        say("How are you!")
        run.log({"messages": 2})

    # Second W&B run
    with wandb.init(
        entity=entity,
        project=project,
        notes="Experiment 2",
        tags=["baseline", "paper1"],
    ) as run:
        say("Hello, world from experiment 2!")
        say("How are you!")
        run.log({"messages": 2})

if __name__ == "__main__":
    # Replace this with your actual W&B username/project
    example_wandb("your-team-name/your-project-name")

4. Run the script.

python weave_trace_with_wandb.py

5. Navigate to the W&B app and select your project.
6. In the Weave project sidebar, click Traces. The Traces table displays links to any associated runs.

You can now open any trace from the Traces table to inspect the linked W&B run and review its associated experiment context.

TypeScript

This feature is not available for the TypeScript SDK yet.