Toward the next release (v2.5.0)

[Miksus]

Hi!

I think Rocketry version 2.5 will be again a significant update in terms of what one can do with Rocketry.

Here is the feature set I aim for the release:

• Multi-launch: allow same task to run multiple times
• Event system: easy way to poll events and trigger tasks
• Logging improvement: make setting the logging easier

Multi-launch (implemented)

The multi-launch system enables running the same task multiple times. The runs are tracked in run stacks. Here is an example:

@app.task(multilaunch=True, execution="async")
async def do_things():
    ...

This task can run four times parallel. Multilaunch can also be set on session config to apply to all tasks by default.

The rocketry.conds.running was also refactored in order to be useful with multi-launch. For example, this will start four parallel runs:

from rocketry.conds import running

@app.task(running < 4, multilaunch=True, execution="async")
async def do_things():
    ...

And this will terminate if there are over 4 runs at the same time:

from rocketry.conds import running

@app.task(end_cond=running > 4, multilaunch=True, execution="async")
async def do_things():
    ...

Event system (close to be done)

The event system enables an easy way to trigger tasks based on some datetimes.

For example, an event notification example:

from datetime import datetime
from rocketry.events import event

@event()
def my_event():
    return datetime(2022, 10, 15, 23, 59)

@app.task(my_event)
def do_things():
    ...

The above will run only when it has not run after the event happened (the datetime in the event).

This also supports event carried state transfer:

from datetime import datetime
from rocketry.events import event, Event

@event()
def my_event():
    return Event(datetime=datetime(2022, 15, 23, 29, value="a value"))

@app.task(my_event)
def do_things(event=my_event):
    ...

The value of the argument event will be a value in the above example. There is also caching and the function my_event is not run when the argument's value is set (as it was already run for the condition check). Futhermore, there is a check_cond that can be customized in order to decrease the amount of function call in case it is expensive (ie. if the event is inspected from a database).

Logging improvements

The logging works well and it has been moderately documented. However, the documentation could be improved and setting up the logging could be made more natural.