Add PVCache #13
Add PVCache #13
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Helper for the ~common case of acting on the values of a group of PVs whenever any of them change.
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I clicked Create too soon. Description updated... |
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There is the |
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Seems reasonable, but I've never needed either this or cothread.pv.PV in any of my projects so I can't comment on whether it fits their use cases. Seems like this is more general (aggregate multiple PVs into a list or dict structure), while the PV (single PV) and PV_array (multiple PVs in a numpy array) are more specific. Maybe @willrogers and @Araneidae can comment on whether these are different ideas or should be merged together into one class?
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| return self.get_nowait() | ||
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| __getitem__ = get |
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How does this work? Doesn't __getitem__ require a key?
| from . import camonitor, CANothing | ||
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| class PVCache: |
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This will need a bit of work to shoehorn typing into it. I guess something like this might work:
| class PVCache: | |
| from typing import TypeVar, List, Dict | |
| T = TypeVar("T") | |
| V = TypeVar("V", Dict[str, T], List[T]) | |
| class PVCache(Generic[V[str]]): | |
| ... | |
| def get_nowait(self) -> V[AugmentedValue]: | |
| ... |
This says if you pass a List[str] as PVs, then you will get a List[AugmentedValue] from get_nowait, and if you pass a Dict[str, str] as PVs you will get a Dict[str, AugmentedValue].
It might work, depends on what mypy supports...
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| __getitem__ = get | ||
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| async def changes(self): |
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| async def changes(self): | |
| async def changed(self): |
| async def __anext__(self): | ||
| while True: | ||
| if self._first: | ||
| # (maybe) deliver initial snapshot immediately |
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Probably needs to be an __init__ option for PVCache
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Unrelated to the code, but since I noticed your usage yesterday when I needed to enable GHA builds for my fork. fyi. It is being reported that this Action was doing nefarious things for several months this spring. |
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Yes, we had to re-roll our PyPI token because of this... |
Maybe useful in some form. I've found myself writing something like this in many CA client scripts. Meant to be used something like
camontor(). Instead ofSubscriptions, returns an object which can be iterated to yield snapshots of cache values whenever there is an update.Or with a larger number of PVs, a dictionary mode.