Link a W&B run to trace function calls

Associate Weave traces with W&B runs for experiment tracking

View a W&B run in the Traces table

With W&B Weave, you can trace function calls in your code and link them directly to the W&B runs in which they were executed. 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. Links to any associated runs are shown in the Traces table.

Python

The following Python code shows how traced Ops are linked to W&B runs when executed 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 actual W&B entity/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 https://wandb.ai and select your project.
6. In the Weave project sidebar, click Traces. Links to any associated runs are displayed in the Traces table.

TypeScript

This feature is not available for the TypeScript SDK yet.