This adds some opentracing annotations to ResponseCache, to make it easier to see what's going on; in particular, it adds a link back to the initial trace which is actually doing the work of generating the response.
When all entries in an `LruCache` have a size of 0 according to the
provided `size_callback`, and `drop_from_cache` is called on a cache
node, the node would be unlinked from the LRU linked list but remain in
the cache dictionary. An assertion would be later be tripped due to the
inconsistency.
Avoid unintentionally calling `__len__` and use a strict `is None`
check instead when unwrapping the weak reference.
Updating mypy past version 0.9 means that third-party stubs are no-longer distributed with typeshed. See http://mypy-lang.blogspot.com/2021/06/mypy-0900-released.html for details.
We therefore pull in stub packages in setup.py
Additionally, some modules that we were previously ignoring import failures for now have stubs. So let's use them.
The rest of this change consists of fixups to make the newer mypy + stubs pass CI.
Co-authored-by: Patrick Cloke <clokep@users.noreply.github.com>
Use `PreserveLoggingContext()` to ensure that logging contexts are not
lost when exiting a read/write lock.
When exiting a read/write lock, callbacks on a `Deferred` are triggered
as a signal to any waiting coroutines. Any waiting coroutine that
becomes runnable is likely to follow the Synapse logging context rules
and will restore its own logging context, then either run to completion
or await another `Deferred`, resetting the logging context in the
process.
The following modules now pass `disallow_untyped_defs`:
* synapse.util.caches.cached_call
* synapse.util.caches.lrucache
* synapse.util.caches.response_cache
* synapse.util.caches.stream_change_cache
* synapse.util.caches.ttlcache pass
* synapse.util.daemonize
* synapse.util.patch_inline_callbacks pass `no-untyped-defs`
* synapse.util.versionstring
Additional typing in synapse.util.metrics. Didn't get this to pass `no-untyped-defs`, think I'll need to watch #10847
Currently we use `JsonEncoder.iterencode` to write JSON responses, which ensures that we don't block the main reactor thread when encoding huge objects. The downside to this is that `iterencode` falls back to using a pure Python encoder that is *much* less efficient and can easily burn a lot of CPU for huge responses. To fix this, while still ensuring we don't block the reactor loop, we encode the JSON on a threadpool using the standard `JsonEncoder.encode` functions, which is backed by a C library.
Doing so, however, requires `respond_with_json` to have access to the reactor, which it previously didn't. There are two ways of doing this:
1. threading through the reactor object, which is a bit fiddly as e.g. `DirectServeJsonResource` doesn't currently take a reactor, but is exposed to modules and so is a PITA to change; or
2. expose the reactor in `SynapseRequest`, which requires updating a bunch of servlet types.
I went with the latter as that is just a mechanical change, and I think makes sense as a request already has a reactor associated with it (via its http channel).
Instead of wrapping the JSON into an object, this creates concrete
instances for Transaction and Edu. This allows for improved type
hints and simplified code.
Mostly this involves decorating a few Deferred declarations with extra type hints. We wrap the types in quotes to avoid runtime errors when running against older versions of Twisted that don't have generics on Deferred.
This PR adds a common configuration section for all modules (see docs). These modules are then loaded at startup by the homeserver. Modules register their hooks and web resources using the new `register_[...]_callbacks` and `register_web_resource` methods of the module API.
This is the first of two PRs which seek to address #8518. This first PR lays the groundwork by extending ResponseCache; a second PR (#10158) will update the SyncHandler to actually use it, and fix the bug.
The idea here is that we allow the callback given to ResponseCache.wrap to decide whether its result should be cached or not. We do that by (optionally) passing a ResponseCacheContext into it, which it can modify.
* Make `invalidate` and `invalidate_many` do the same thing
... so that we can do either over the invalidation replication stream, and also
because they always confused me a bit.
* Kill off `invalidate_many`
* changelog
`keylen` seems to be a thing that is frequently incorrectly set, and we don't really need it.
The only time it was used was to figure out if we had removed a subtree in `del_multi`, which we can do better by changing `TreeCache.pop` to return a different type (`TreeCacheNode`).
Commits should be independently reviewable.
Patrick Cloke