Trigger on new versions

An artifact trigger runs a task automatically whenever a new version of a named artifact lands. Use it to validate every new model, retrain when a dataset is refreshed, or kick off batch inference when fresh data arrives.

A trigger is a flyte.Trigger whose automation is flyte.OnArtifact. The flyte.TriggeredArtifact sentinel marks which task input receives the new version:

        
    
import flyte
from flyte.io import File

env = flyte.TaskEnvironment(name="validation")

retrain = flyte.Trigger(
    name="retrain-on-new-model",
    automation=flyte.OnArtifact(name="customer_model"),
    inputs={"model": flyte.TriggeredArtifact, "threshold": 0.5},
    description="Validate every new customer_model version",
)


@env.task(triggers=(retrain,))
async def validate(model: File, threshold: float = 0.5) -> str:
    ...

Deploy the environment to register the trigger:

flyte deploy validation.py env

From then on, every new version of customer_model in the task’s project and domain starts a run of validate, with the new version bound to the model input. The task body sees an ordinary File or Dir and needs no artifact-specific code.

What counts as a new version

The trigger fires no matter how the version was published: a task output wrapped with flyte.artifacts.new(), an upload through flyte.remote.Artifact.create() or flyte create artifact, or a Hugging Face prefetch. This makes triggers a clean handoff point between external processes and your pipelines: a partner drops a dataset, publishes it as an artifact, and your processing task starts on its own.

By default any new version fires the trigger. Pass version= to flyte.OnArtifact to fire only when that exact version is published.

Rules

At most one input can be flyte.TriggeredArtifact.
flyte.TriggeredArtifact requires the automation to be flyte.OnArtifact.
flyte.TriggerTime cannot be combined with flyte.OnArtifact; it is for schedule triggers.

All other inputs must have values in the trigger definition or defaults on the task, the same as schedule triggers.