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Naming change `cache` -> `_Cache`

context_caching
Tyler Goodlet 2021-12-15 08:16:31 -05:00
parent 4a0252baf2
commit b210278e2f
1 changed files with 23 additions and 23 deletions
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46
tractor/trionics/_mngrs.py
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@ -112,10 +112,10 @@ async def gather_contexts(
# Further potential examples of interest:
# https://gist.github.com/njsmith/cf6fc0a97f53865f2c671659c88c1798#file-cache-py-L8
class cache:
class _Cache:
'''
Globally (processs wide) cached, task access to a
kept-alive-while-in-use async resource.
Globally (actor-processs scoped) cached, task access to
a kept-alive-while-in-use async resource.
'''
lock = trio.Lock()
@ -156,12 +156,12 @@ async def maybe_open_context(
) -> AsyncIterator[tuple[bool, T]]:
'''
Maybe open a context manager if there is not already a cached
version for the provided ``key``. Return the cached instance on
a cache hit.
Maybe open a context manager if there is not already a _Cached
version for the provided ``key``. Return the _Cached instance on
a _Cache hit.
'''
await cache.lock.acquire()
await _Cache.lock.acquire()
ctx_key = id(mngr)
@ -169,17 +169,17 @@ async def maybe_open_context(
try:
# lock feed acquisition around task racing / ``trio``'s
# scheduler protocol
value = cache.values[key]
log.info(f'Reusing cached resource for {key}')
cache.users += 1
cache.lock.release()
value = _Cache.values[key]
log.info(f'Reusing _Cached resource for {key}')
_Cache.users += 1
_Cache.lock.release()
yield True, value
except KeyError:
log.info(f'Allocating new resource for {key}')
# **critical section** that should prevent other tasks from
# checking the cache until complete otherwise the scheduler
# checking the _Cache until complete otherwise the scheduler
# may switch and by accident we create more then one feed.
# TODO: avoid pulling from ``tractor`` internals and
@ -187,28 +187,28 @@ async def maybe_open_context(
service_n = current_actor()._service_n
# TODO: does this need to be a tractor "root nursery"?
assert not cache.resources.get(ctx_key), f'Resource exists? {ctx_key}'
ln, _ = cache.resources[ctx_key] = (service_n, trio.Event())
assert not _Cache.resources.get(ctx_key), f'Resource exists? {ctx_key}'
ln, _ = _Cache.resources[ctx_key] = (service_n, trio.Event())
value = await ln.start(cache.run_ctx, mngr, key)
cache.users += 1
cache.lock.release()
value = await ln.start(_Cache.run_ctx, mngr, key)
_Cache.users += 1
_Cache.lock.release()
yield False, value
finally:
cache.users -= 1
if cache.lock.locked():
cache.lock.release()
_Cache.users -= 1
if value is not None:
# if no more consumers, teardown the client
if cache.users <= 0:
if _Cache.users <= 0:
log.info(f'De-allocating resource for {key}')
if _Cache.lock.locked():
_Cache.lock.release()
# terminate mngr nursery
entry = cache.resources.get(ctx_key)
entry = _Cache.resources.get(ctx_key)
if entry:
_, no_more_users = entry
no_more_users.set()