PrefectHQ/prefect 3.0.0rc2 on GitHub

We're excited to announce the release candidate of Prefect 3.0. It's the most flexible, powerful, fastest version of Prefect yet. Prefect 3.0 includes several exciting new features. Install it by running pip install prefect==3.0.0rc2 and check out the docs here.

Run tasks independently of flows

You can now run and serve tasks outside of flows and inside of other tasks.

from prefect import task

@task
def my_background_task(name: str):
    print(f"Hello, {name}!")

if __name__ == "__main__":
    my_background_task.delay("ford")

Transactional semantics

Use rollback and commit hooks to facilitate idempotent python code.

from prefect import flow, task
from prefect.transactions import transaction
@task
def first_task():
    print('first')

@first_task.on_rollback
def roll(txn):
    print('rolling back')

@task
def second_task():
    raise RuntimeError("oopsie")

@flow
def txn_flow():
    with transaction():
        first_task()
        second_task()
if __name__ == "__main__":
    txn_flow()

Open source Events and Automations

Trigger actions, such as sending notifications, pausing schedules, starting flow runs and more in response to Prefect events.

More flexible variables and new artifact types

Variables can now be any JSON compatible type including dicts, lists, and integers. Progress and Image artifacts make it easy to add visual annotations to your flow run graph.

Faster and richer CLI

Improved CLI speed and several added commands and conveniences.

Updated navigation, styling, and interaction design

The new Runs page displays both flow and task run information, and an improved sidebar and switcher makes navigating Prefect simpler than ever.

Changes since `3.0.0rc1`

Enhancements

Adds deferred kwarg to Task.map to executed mapped tasks on a task server by @desertaxle in #13756
Add pydantic version to cli version command by @pleek91 in #13715
conditionally log retryable errors by @jakekaplan in #13773
Update Variable.set return value + docs by @jakekaplan in #13557
Add new flow runs pagination endpoint by @pleek91 in #13808
Updates PrefectDistributedFuture to use an event websocket to determine task completion by @desertaxle in #13763
Enhancement: Artifacts documentation by @dylanbhughes in #13724
Migrate prefect-kubernetes to pydantic 2 by @zzstoatzz in #13687
Add endpoint for bulk task run counts for flow runs by @pleek91 in #13759
Copy pared down prefect-redis to integrations by @bunchesofdonald in #13758
Cache key policies by @cicdw in #13791
Refactor task run engine by @jlowin in #13793
Cache Policy Upgrades by @cicdw in #13821
Put AwsCredentials first to match default factory by @bunchesofdonald in #13819

Fixes

Fix load_flow_argument_from_entrypoint to work with async flows by @elisalimli in #13716
Add handling for positional only and keyword only arguments when parsing a function signature from source code by @desertaxle in #13774
Load assignments when safeloading a namespace by @desertaxle in #13775
Coerce work pool env values to str by @zzstoatzz in #13782
Support retry_delay_seconds in task engine by @zzstoatzz in #13815
Rename RedisFilesystem to RedisStorageContainer to match naming semantics of other filesystem classes by @bunchesofdonald in #13771

Documentation

Fixes over 500 broken links in docs by @discdiver in #13734
Remove agents concept page and refs for 3.0 by @serinamarie in #13631
WIP 3.0rc docs new IA (on Mintlify) by @LarryUllman in #13783
Fixes a doc build from an admonition change and note managed execution not in beta. by @discdiver in #13789
Update version instruction install docs page by @discdiver in #13795
Move integration package docs out of versioning by @discdiver in #13760
Update button text at top of page by @discdiver in #13797
Update get-started/install page by @LarryUllman in #13822
Porting over task guide, mdx bugfixes by @WillRaphaelson in #13754

New Contributors

@elisalimli made their first contribution in #13716
@LarryUllman made their first contribution in #13783

Full Changelog: 3.0.0rc1...3.0.0rc2

PrefectHQ/prefect 3.0.0rc2 Release 3.0.0rc2 on GitHub