Prefect

Breaking Changes
- Remove deprecated ability to use `deployment.yaml` in `prefect deploy` — https://github.com/PrefectHQ/prefect/pull/12731
- Remove deprecated ability to pass `-f/--flow` as option to `prefect deploy` — https://github.com/PrefectHQ/prefect/pull/12732
- Remove deprecated `projects` from `prefect deploy` — https://github.com/PrefectHQ/prefect/pull/12737
- Remove deprecated `--ci` option from `prefect deploy` — https://github.com/PrefectHQ/prefect/pull/12740

Enhancements
- Improve account selection in `prefect cloud login` and `workspace set` — https://github.com/PrefectHQ/prefect/pull/12717


**Full Changelog:** https://github.com/PrefectHQ/prefect/compare/2.17.0...2.18.0

See [the release notes](https://github.com/PrefectHQ/prefect/blob/1006d2d8af397f3bf00218be3783b992144b3da6/RELEASE-NOTES.md#release-2180) for more!

Fixes
- Fix events storage import — https://github.com/PrefectHQ/prefect/pull/12681
- Remove `opentelemetry` import — https://github.com/PrefectHQ/prefect/pull/12684

**All changes**: https://github.com/PrefectHQ/prefect/compare/2.17.0...2.17.1

🧮 Manage Prefect variables via the Python SDK

Prefect variables are useful for storing and reusing data and configuration between and across workflows; and previously you could only create and update variables via the Prefect UI. With this release, you can now get and set Prefect variables directly in your Python code with the new `Variable.set` and `Variable.get` methods!

For an example of reading and writing variable values in Python see the following example:

python
from prefect.variables import Variable

set a variable
variable = Variable.set(name="the_answer", value="42")

get a variable
answer = Variable.get('the_answer')
print(answer.value)
42

get a variable with a default value
answer = Variable.get('not_the_answer', default='42')
print(answer.value)
42

update a variable
answer = Variable.set(name="the_answer", value="43", overwrite=True)
print(answer.value)
43


Refer to the [docs](https://docs.prefect.io/latest/guides/variables/#accessing-variables) for more information and see the PR for implementation details: https://github.com/PrefectHQ/prefect/pull/12596

Other Enhancements 🌟
- Allow flows inside tasks
— https://github.com/PrefectHQ/prefect/pull/12559
— https://github.com/PrefectHQ/prefect/pull/12607
- Add `User-Agent` header containing the running Prefect version — https://github.com/PrefectHQ/prefect/pull/12601
- Adds deployment version to the flow run object — https://github.com/PrefectHQ/prefect/pull/12591

... and numerous 🐛 fixes!

**Full Changelog:** https://github.com/PrefectHQ/prefect/compare/2.16.9...2.17.0

See [the release notes](https://github.com/PrefectHQ/prefect/blob/main/RELEASE-NOTES.md#release-2170) for more!

This release includes a number of enhancements and in-flight feature work.

🛠✨ One such enhancement helps streamline our CLI by adding a `-jv/--job-variable` option to `prefect deploy`, on par with the option available in `prefect deployment run`.

🔄🔗 In terms of enhancing existing Prefect concepts, we've removed a constraint that prevented tasks from being called from other tasks. For example, this allows you to call tasks within tasks within a flow.

🗿 📉 We no longer create artifacts for unpersisted results, which should prevent an influx of entries to the `artifact` table. Retried flows without persisted results will now have an error message stating that the "State data is missing" rather than referencing an "unpersisted result".

See the [release notes](https://github.com/PrefectHQ/prefect/blob/main/RELEASE-NOTES.md#release-2169) for more details!

Fixes

- Disable CSRF protection by default - https://github.com/PrefectHQ/prefect/pull/12479
- Fix issue that caused UI to not be built when creating docker images - https://github.com/PrefectHQ/prefect/pull/12481

💻 Introducing `prefect shell` for observing CLI commands
You can now observe CLI commands as a Prefect flow. For example:
python
» prefect shell watch "curl http://wttr.in/Chicago?format=3"