diff options
Diffstat (limited to 'synapse/util')
| -rw-r--r-- | synapse/util/caches/response_cache.py | 106 | ||||
| -rw-r--r-- | synapse/util/file_consumer.py | 4 | ||||
| -rw-r--r-- | synapse/util/logcontext.py | 1 |
3 files changed, 108 insertions, 3 deletions
diff --git a/synapse/util/caches/response_cache.py b/synapse/util/caches/response_cache.py index 00af539880..7f79333e96 100644 --- a/synapse/util/caches/response_cache.py +++ b/synapse/util/caches/response_cache.py @@ -12,8 +12,15 @@ # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. +import logging + +from twisted.internet import defer from synapse.util.async import ObservableDeferred +from synapse.util.caches import metrics as cache_metrics +from synapse.util.logcontext import make_deferred_yieldable, run_in_background + +logger = logging.getLogger(__name__) class ResponseCache(object): @@ -24,20 +31,68 @@ class ResponseCache(object): used rather than trying to compute a new response. """ - def __init__(self, hs, timeout_ms=0): + def __init__(self, hs, name, timeout_ms=0): self.pending_result_cache = {} # Requests that haven't finished yet. self.clock = hs.get_clock() self.timeout_sec = timeout_ms / 1000. + self._name = name + self._metrics = cache_metrics.register_cache( + "response_cache", + size_callback=lambda: self.size(), + cache_name=name, + ) + + def size(self): + return len(self.pending_result_cache) + def get(self, key): + """Look up the given key. + + Can return either a new Deferred (which also doesn't follow the synapse + logcontext rules), or, if the request has completed, the actual + result. You will probably want to make_deferred_yieldable the result. + + If there is no entry for the key, returns None. It is worth noting that + this means there is no way to distinguish a completed result of None + from an absent cache entry. + + Args: + key (hashable): + + Returns: + twisted.internet.defer.Deferred|None|E: None if there is no entry + for this key; otherwise either a deferred result or the result + itself. + """ result = self.pending_result_cache.get(key) if result is not None: + self._metrics.inc_hits() return result.observe() else: + self._metrics.inc_misses() return None def set(self, key, deferred): + """Set the entry for the given key to the given deferred. + + *deferred* should run its callbacks in the sentinel logcontext (ie, + you should wrap normal synapse deferreds with + logcontext.run_in_background). + + Can return either a new Deferred (which also doesn't follow the synapse + logcontext rules), or, if *deferred* was already complete, the actual + result. You will probably want to make_deferred_yieldable the result. + + Args: + key (hashable): + deferred (twisted.internet.defer.Deferred[T): + + Returns: + twisted.internet.defer.Deferred[T]|T: a new deferred, or the actual + result. + """ result = ObservableDeferred(deferred, consumeErrors=True) self.pending_result_cache[key] = result @@ -53,3 +108,52 @@ class ResponseCache(object): result.addBoth(remove) return result.observe() + + def wrap(self, key, callback, *args, **kwargs): + """Wrap together a *get* and *set* call, taking care of logcontexts + + First looks up the key in the cache, and if it is present makes it + follow the synapse logcontext rules and returns it. + + Otherwise, makes a call to *callback(*args, **kwargs)*, which should + follow the synapse logcontext rules, and adds the result to the cache. + + Example usage: + + @defer.inlineCallbacks + def handle_request(request): + # etc + defer.returnValue(result) + + result = yield response_cache.wrap( + key, + handle_request, + request, + ) + + Args: + key (hashable): key to get/set in the cache + + callback (callable): function to call if the key is not found in + the cache + + *args: positional parameters to pass to the callback, if it is used + + **kwargs: named paramters to pass to the callback, if it is used + + Returns: + twisted.internet.defer.Deferred: yieldable result + """ + result = self.get(key) + if not result: + logger.info("[%s]: no cached result for [%s], calculating new one", + self._name, key) + d = run_in_background(callback, *args, **kwargs) + result = self.set(key, d) + elif not isinstance(result, defer.Deferred) or result.called: + logger.info("[%s]: using completed cached result for [%s]", + self._name, key) + else: + logger.info("[%s]: using incomplete cached result for [%s]", + self._name, key) + return make_deferred_yieldable(result) diff --git a/synapse/util/file_consumer.py b/synapse/util/file_consumer.py index 90a2608d6f..3c8a165331 100644 --- a/synapse/util/file_consumer.py +++ b/synapse/util/file_consumer.py @@ -17,7 +17,7 @@ from twisted.internet import threads, reactor from synapse.util.logcontext import make_deferred_yieldable, preserve_fn -import Queue +from six.moves import queue class BackgroundFileConsumer(object): @@ -49,7 +49,7 @@ class BackgroundFileConsumer(object): # Queue of slices of bytes to be written. When producer calls # unregister a final None is sent. - self._bytes_queue = Queue.Queue() + self._bytes_queue = queue.Queue() # Deferred that is resolved when finished writing self._finished_deferred = None diff --git a/synapse/util/logcontext.py b/synapse/util/logcontext.py index d660ec785b..d59adc236e 100644 --- a/synapse/util/logcontext.py +++ b/synapse/util/logcontext.py @@ -92,6 +92,7 @@ class LoggingContext(object): def __nonzero__(self): return False + __bool__ = __nonzero__ # python3 sentinel = Sentinel() |