hatchet/examples/python/durable_eviction/worker.py

from __future__ import annotations

import asyncio
from datetime import timedelta
from typing import Any

from hatchet_sdk import Context, DurableContext, EmptyModel, Hatchet, UserEventCondition
from hatchet_sdk.runnables.eviction import EvictionPolicy
from pydantic import BaseModel

hatchet = Hatchet()


EVICTION_TTL_SECONDS = 5
LONG_SLEEP_SECONDS = 15
EVENT_KEY = "durable-eviction:event"

EVICTION_POLICY = EvictionPolicy(
    ttl=timedelta(seconds=EVICTION_TTL_SECONDS),
    allow_capacity_eviction=True,
    priority=0,
)


@hatchet.task()
async def child_task(input: EmptyModel, ctx: Context) -> dict[str, Any]:
    """Simple child that sleeps long enough for the parent's TTL to fire."""
    await asyncio.sleep(LONG_SLEEP_SECONDS)
    return {"child_status": "completed"}


@hatchet.durable_task(
    execution_timeout=timedelta(minutes=5),
    eviction_policy=EVICTION_POLICY,
)
async def evictable_sleep(input: EmptyModel, ctx: DurableContext) -> dict[str, Any]:
    """Sleeps long enough for the TTL-based eviction to kick in."""
    await ctx.aio_sleep_for(timedelta(seconds=LONG_SLEEP_SECONDS))
    return {"status": "completed"}


@hatchet.durable_task(
    execution_timeout=timedelta(minutes=5),
    eviction_policy=EVICTION_POLICY,
)
async def evictable_wait_for_event(
    input: EmptyModel, ctx: DurableContext
) -> dict[str, Any]:
    """Waits for a user event -- long enough for TTL eviction to fire."""
    await ctx.aio_wait_for_event(
        EVENT_KEY,
        "true",
    )
    return {"status": "completed"}


@hatchet.durable_task(
    execution_timeout=timedelta(minutes=5),
    eviction_policy=EVICTION_POLICY,
)
async def evictable_child_spawn(
    input: EmptyModel, ctx: DurableContext
) -> dict[str, Any]:
    """Spawns a child workflow whose runtime exceeds the eviction TTL."""
    child_result = await child_task.aio_run()
    return {"child": child_result, "status": "completed"}


class BulkChildTaskInput(BaseModel):
    sleep_for: timedelta


@hatchet.task(
    input_validator=BulkChildTaskInput,
)
async def bulk_child_task(
    input: BulkChildTaskInput, ctx: Context
) -> dict[str, str | int]:
    """Simple child that sleeps long enough for the parent's TTL to fire."""
    await asyncio.sleep(input.sleep_for.total_seconds())
    return {"sleep_for": int(input.sleep_for.total_seconds()), "status": "completed"}


@hatchet.durable_task(
    execution_timeout=timedelta(minutes=5),
    eviction_policy=EVICTION_POLICY,
)
async def evictable_child_bulk_spawn(
    input: EmptyModel, ctx: DurableContext
) -> dict[str, Any]:
    child_results = await child_task.aio_run_many(
        [
            bulk_child_task.create_bulk_run_item(
                input=BulkChildTaskInput(
                    sleep_for=timedelta(seconds=(EVICTION_TTL_SECONDS + 5) * (i + 1))
                ),
                key=f"child{i}",
            )
            for i in range(3)
        ]
    )
    return {"child_results": child_results}


@hatchet.durable_task(
    execution_timeout=timedelta(minutes=5),
    eviction_policy=EVICTION_POLICY,
)
async def multiple_eviction(input: EmptyModel, ctx: DurableContext) -> dict[str, Any]:
    """Sleeps twice, expecting eviction+restore after each sleep."""
    await ctx.aio_sleep_for(timedelta(seconds=LONG_SLEEP_SECONDS))
    await ctx.aio_sleep_for(timedelta(seconds=LONG_SLEEP_SECONDS))
    return {"status": "completed"}


CAPACITY_EVICTION_POLICY = EvictionPolicy(
    ttl=None,
    allow_capacity_eviction=True,
    priority=0,
)

CAPACITY_SLEEP_SECONDS = 20


@hatchet.durable_task(
    execution_timeout=timedelta(minutes=5),
    eviction_policy=CAPACITY_EVICTION_POLICY,
)
async def capacity_evictable_sleep(
    input: EmptyModel, ctx: DurableContext
) -> dict[str, Any]:
    """No TTL -- only evictable via capacity pressure (durable_slots=1)."""
    await ctx.aio_sleep_for(timedelta(seconds=CAPACITY_SLEEP_SECONDS))
    return {"status": "completed"}


@hatchet.durable_task(
    execution_timeout=timedelta(minutes=5),
    eviction_policy=EvictionPolicy(
        ttl=None,
        allow_capacity_eviction=False,
        priority=0,
    ),
)
async def non_evictable_sleep(input: EmptyModel, ctx: DurableContext) -> dict[str, Any]:
    """Has eviction disabled -- should never be evicted."""
    await ctx.aio_sleep_for(timedelta(seconds=10))
    return {"status": "completed"}


def main() -> None:
    worker = hatchet.worker(
        "eviction-worker",
        workflows=[
            evictable_sleep,
            evictable_wait_for_event,
            evictable_child_spawn,
            evictable_child_bulk_spawn,
            multiple_eviction,
            non_evictable_sleep,
            child_task,
            bulk_child_task,
        ],
    )
    worker.start()


if __name__ == "__main__":
    main()