feat(api): Add locks on direct data access for mag and temp module #4501
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- Remove backcompat wrapper tests since we have no backcompat wrapper now - Remove V1 json protocol execution since it is pointless now - Fix our test fixtures to not consider the v1/v2 split for anything that - doesn't really need it - Fix our tests to deal with the new test fixtures Upshot: tests run faster now, and also we can test apiv2 deck cal cli for the first time.
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The changes to make the magdeck get its information from the hardware look good. The locking is a bit wrong though.
What we want to do with the locking is add it at the highest atomic layer we can - at the place where you can't have any interruptions. That place is in driver send/receive. We want to make sure that the driver holds the lock from before it starts sending to after it's done receiving, including any retries in the middle. Those places aren't unfortunately all going through the same paths in the driver - for instance, magdeck recursive_write_and_return vs raw _send_command - but all those places are where they need to be.
Finally, the locks actually need to be in a place where multiple things can contend for them. That means that each driver file should have a module-scope map of module port to lock, and individual driver instances acquire the lock that corresponds to their port. The way it is now, with each module instance having its own lock, protects against multiple threads accessing a specific module:
thread-1 thread-2
td.set_temperature()
-> acquire td.set_temperature()
-> write -> acquire waits....
-> read ...
-> release acquires
returns -> write
but it doesn't protect against multiple module instances in different threads:
thread-1, td-1 thread-2, td-2
set_temperature
-> acquires lock-1 set_temperature
-> writes -> acquires lock-2
-> reads -> writes # possible collision!
which is the thing we're most concerned about, since we'll have a v1 module object and v2 module object talking to the same hardware.
Codecov Report
@@ Coverage Diff @@
## edge #4501 +/- ##
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+ Coverage 55.46% 57.4% +1.93%
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Files 909 917 +8
Lines 26743 28482 +1739
=========================================
+ Hits 14834 16350 +1516
- Misses 11909 12132 +223
Continue to review full report at Codecov.
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| if not lock_for_port: | ||
| mag_locks[port] = Lock() | ||
| lock_for_port = mag_locks.get(port) | ||
| self._lock = lock_for_port |
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Probably want to look this up from the global every time unfortunately
| @@ -46,6 +46,8 @@ | |||
| # to/from Temp-Deck | |||
| GCODE_ROUNDING_PRECISION = 3 | |||
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| mag_locks: Dict[str, object] = {} | |||
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this can be Dict[str, threading.Lock] right
| @@ -68,8 +68,10 @@ def connect(self, port=None) -> Optional[str]: | |||
| self.disconnect(port) | |||
| self._connect_to_port(port) | |||
| if temp_locks.get(port): | |||
| print("in here") | |||
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Remove the print statements in line 71 & 74
Everything else looks good to me!!
overview
Add locks on both the temperature and magnetic modules to prevent multi-access to data from the hardware.
review requests
Test Plan