fix: timeout context manager on Windows

[betodealmeida]

SUMMARY

We currently use a context manager to timeout queries that run in SQL Lab, eg:

with utils.timeout(seconds=timeout, error_message=timeout_msg):
    data = sql_lab.get_sql_results(...)

The context manager uses SIGALRM, which is not available in Windows, resulting in an error (see #12824).

Even though Windows is not technically supported by Superset, this is a simple fix. I introduced a new timeout context manager based on a timer. This PR changes Superset to use that context manager only when running on Windows. In theory we could replace the old one, but I thought it would be safer to introduce the new one in parallel first.

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

N/A

TEST PLAN

I installed Python under a Windows VPS and tested the context manager with this script:

# test.py
import _thread
import threading


class Timeout:
    def __init__(self, seconds: int = 1, error_message: str = "Timeout") -> None:
        self.seconds = seconds
        self.error_message = error_message
        self.timer = threading.Timer(self.seconds, _thread.interrupt_main)

    def __enter__(self) -> None:
        self.timer.start()

    def __exit__(self, type, value, traceback) -> None:
        self.timer.cancel()
        if type is KeyboardInterrupt:
            raise Exception(self.error_message)


with Timeout():
    for i in range(int(1e15)):
        pass

(I didn't use sleep() because the _thread.interrupt_main doesn't interrupt it.)

Then running it causes the main thread to be aborted after 1 second:

C:\Users\Administrator\Documents>powershell -Command "Measure-Command {python test.py}"
Traceback (most recent call last):
  File "C:\Users\Administrator\Documents\test.py", line 21, in <module>
    pass
KeyboardInterrupt

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "C:\Users\Administrator\Documents\test.py", line 21, in <module>
    pass
  File "C:\Users\Administrator\Documents\test.py", line 16, in __exit__
    raise Exception(self.error_message)
Exception: Timeout


Days              : 0
Hours             : 0
Minutes           : 0
Seconds           : 1
Milliseconds      : 463
Ticks             : 14631515
TotalDays         : 1.69346238425926E-05
TotalHours        : 0.000406430972222222
TotalMinutes      : 0.0243858583333333
TotalSeconds      : 1.4631515
TotalMilliseconds : 1463.1515




C:\Users\Administrator\Documents>

ADDITIONAL INFORMATION

• Has associated issue: Error running SQL Lab #12824
• Changes UI
• Requires DB Migration.
• Confirm DB Migration upgrade and downgrade tested.
• Introduces new feature or API
• Removes existing feature or API

[codecov-io]

Codecov Report

Merging #13041 (0b978ff) into master (2ce7982) will increase coverage by 13.93%.
The diff coverage is 57.14%.

@@             Coverage Diff             @@
##           master   #13041       +/-   ##
===========================================
+ Coverage   53.06%   66.99%   +13.93%     
===========================================
  Files         489      489               
  Lines       17314    28794    +11480     
  Branches     4482        0     -4482     
===========================================
+ Hits         9187    19291    +10104     
- Misses       8127     9503     +1376     

Flag	Coverage Δ
cypress	?
python	66.99% <57.14%> (?)

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
superset/config.py	90.64% <ø> (ø)
...s/260bf0649a77_migrate_x_dateunit_in_time_range.py	0.00% <0.00%> (ø)
superset/utils/core.py	87.55% <53.33%> (ø)
superset/charts/commands/exceptions.py	92.85% <77.77%> (ø)
superset/utils/date_parser.py	96.87% <100.00%> (ø)
...t-frontend/src/dashboard/util/setPeriodicRunner.ts
...et-frontend/src/components/ConfirmStatusChange.tsx
...perset-frontend/src/views/CRUD/welcome/Welcome.tsx
...perset-frontend/src/dashboard/util/findParentId.js
...ore/components/controls/DateFilterControl/utils.ts
... and 968 more

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[villebro]

LGTM - this has probably been the main barrier causing Superset no not be supported on Windows. Cautiously optimistic that we could start supporting this platform, too.

[villebro]

Surprised that this is a KeyboardInterrupt

[betodealmeida]

Me too!