ConnectionPool can't be used after .resize(..., reset=True) (resolves #2018)

[FrankK-1234]

Hi, can you please have a look at this pull request. It addresses the issue #2018.

What did I do to tackle the issue. First I added several test case for the resize method (in test_connection.py), as they were not available. Basically the test test_acquire_resize_reset() triggered the given issue.

In short the use of force_close_all() (used also in other cases) caused the pool to be set on _closed = True. In the acquire method this resulted in the RuntimeError('Acquire on closed pool').

I've added a parameter close_pool in force_close_all with default of True (old behaviour as used by other callers), which allows the pool to be kept open if set to False. In the resize method, reset branch I've added force_close_all(close_pool=False).

PLEASE NOTE: While testing the resize I've found 2 issues related to resizing which I think are a problem. They are addressed as well.

• Issue 1. The resize calls the setup from within connectionPool and channelPool. This method allocated resource based on the current setting of limit. This works fine for fresh pools however if it is called within the resize then with acquired/dirty resources then it would create to many resources. I fixed this by subtracting the amount of dirty resource from the limit. See connection.py:1069/1095
• Issue 2. The _shrink_down (only called by resize) did not keep in mind the dirty resources and would not correctly shrink if there were dirty resouces. Now it shrink resources and leaves the dirty one as it was before. See resource.py:220

Please have a look at the changes, Regards,

Frank

[thedrow]

Thank you for the contribution!

[spumer]

Good news!

Guys, only one question: why method setup() exists? Looks like pool can create new entry by calling .new() when it's required and limit not reached.

Due setup() calling we create "lazy" objects, then we check it "lazy" or not (in acquire()), and evaluate in prepare(). Looks like removing pre-filling pool should simplify Resource class and all related logic.