Triggers

A trigger is a named, pre-bound way to run a task. It carries the inputs, env vars, queue, notifications, and other run settings that a run started through it should use. A trigger can also carry an automation that fires it on its own, such as a schedule. A trigger with no automation is fired on demand only.

        
import flyte
from datetime import datetime

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

@env.task(triggers=flyte.Trigger.hourly())
def hourly_task(trigger_time: datetime, x: int = 1) -> str:
    return f"Hourly example executed at {trigger_time.isoformat()} with x={x}"

Deploy the task with flyte deploy and the trigger starts creating runs every hour.

In Flyte 1 these were configured with a LaunchPlan (the flytekit.LaunchPlan API) and CronSchedule. Flyte 2 replaces them with flyte.Trigger and flyte.Cron.

Types of automation

The automation argument of flyte.Trigger decides what fires it. Each kind can also bind a value into one of the task’s inputs.

Kind	Automation	Fires when	Binds into inputs	Details
Scheduled	`flyte.Cron("0 9 * * *", timezone=...)`	A cron expression matches	`flyte.TriggerTime`	Schedule triggers
Scheduled	`flyte.FixedRate(60, start_time=...)`	Every N minutes	`flyte.TriggerTime`	Schedule triggers
Scheduled	`flyte.Trigger.hourly()`, `daily()`, `weekly()`, `monthly()`	Predefined cron shortcuts	`flyte.TriggerTime`	Predefined schedules
Manual	None	Only when fired from the UI or with `flyte.run(trigger)`	None	Manual triggers

Every trigger, whatever its automation, can also be fired on demand.

Support is coming for other trigger types, such as:

Webhook triggers: Hit an API endpoint to run your task.
Artifact triggers: Run a task when a specific artifact is produced.

In this section

Configure a trigger Define a flyte.Trigger on a task, bind its inputs, and attach several triggers to one task. Schedule triggers Run a task on a cron expression or a fixed interval with flyte.Cron, flyte.FixedRate, or a predefined schedule. When scheduled runs start When the first run of a cron or fixed-rate trigger happens, depending on activation and start_time. Manual triggers and firing on demand Save named launch configurations for a task with triggers that have no automation, and fire any trigger from the UI or Python. Notifications Send Slack, email, Teams, or webhook notifications when a run started by a trigger ends. Deploy and manage triggers Deploy triggers with their task, activate or deactivate them, and delete them.