docs/docs/pipelines/valves.md

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3	⚙️ Valves

Valves

Valves are input variables that are set per pipeline. Valves are set as a subclass of the Pipeline class, and initialized as part of the __init__ method of the Pipeline class.

When adding valves to your pipeline, include a way to ensure that valves can be reconfigured by admins in the web UI. There are a few options for this:

• Use os.getenv() to set an environment variable to use for the pipeline, and a default value to use if the environment variable isn't set. An example can be seen below:

self.valves = self.Valves(
    **{
        "LLAMAINDEX_OLLAMA_BASE_URL": os.getenv("LLAMAINDEX_OLLAMA_BASE_URL", "http://localhost:11434"),
        "LLAMAINDEX_MODEL_NAME": os.getenv("LLAMAINDEX_MODEL_NAME", "llama3"),
        "LLAMAINDEX_EMBEDDING_MODEL_NAME": os.getenv("LLAMAINDEX_EMBEDDING_MODEL_NAME", "nomic-embed-text"),
    }
)

• Set the valve to the Optional type, which will allow the pipeline to load even if no value is set for the valve.

class Pipeline:
    class Valves(BaseModel):
        target_user_roles: List[str] = ["user"]
        max_turns: Optional[int] = None

If you don't leave a way for valves to be updated in the web UI, you'll see the following error in the Pipelines server log after trying to add a pipeline to the web UI: WARNING:root:No Pipeline class found in <pipeline name>