This commit improves error handling in Flodgatt's main request-response loop, including the portions of that loop that were revised in #128.
This nearly completes the addition of more explicit error handling, but there will be a smaller part 3 to bring the handling of configuration/Postgres errors into conformity with the style here.
This squashed commit makes a fairly significant structural change to significantly reduce Flodgatt's CPU usage.
Flodgatt connects to Redis in a single (green) thread, and then creates a new thread to handle each WebSocket/SSE connection. Previously, each thread was responsible for polling the Redis thread to determine whether it had a message relevant to the connected client. I initially selected this structure both because it was simple and because it minimized memory overhead – no messages are sent to a particular thread unless they are relevant to the client connected to the thread. However, I recently ran some load tests that show this approach to have unacceptable CPU costs when 300+ clients are simultaneously connected.
Accordingly, Flodgatt now uses a different structure: the main Redis thread now announces each incoming message via a watch channel connected to every client thread, and each client thread filters out irrelevant messages. In theory, this could lead to slightly higher memory use, but tests I have run so far have not found a measurable increase. On the other hand, Flodgatt's CPU use is now an order of magnitude lower in tests I've run.
This approach does run a (very slight) risk of dropping messages under extremely heavy load: because a watch channel only stores the most recent message transmitted, if Flodgatt adds a second message before the thread can read the first message, the first message will be overwritten and never transmitted. This seems unlikely to happen in practice, and we can avoid the issue entirely by changing to a broadcast channel when we upgrade to the most recent Tokio version (see #75).
* Initial work to support structured errors
* WIP error handling and RedisConn refactor
* WIP for error handling refactor
* Finish substantive work for Redis error handling
* Apply clippy lints
* Prevent Reciever from querying postgres
Before this commit, the Receiver would query Postgres for the name
associated with a hashtag when it encountered one not in its cache.
This ensured that the Receiver never encountered a (valid) hashtag id
that it couldn't handle, but caused a extra DB query and made
independent sections of the code more entangled than they need to be.
Now, we pass the relevant tag name to the Receiver when it first
starts managing a new subscription and it adds the tag name to its
cache then.
* Improve module boundary/privacy
* Reorganize Receiver to cut RedisStream
* Fix tests for code reorganization
Note that this change includes testing some private functionality by
exposing it publicly in tests via conditional compilation. This
doesn't expose that functionality for the benchmarks, so the benchmark
tests do not currently pass without adding a few `pub use`
statements. This might be worth changing later, but benchmark tests
aren't part of our CI and it's not hard to change when we want to test
performance.
This change also cuts the benchmark tests that were benchmarking old
ways Flodgatt functioned. Those were useful for comparison purposes,
but have served their purpose – we've firmly moved away from the
older/slower approach.
* Fix Receiver for tests
* Fix panic on delete events
Previously, the code attempted to check the toot's language regardless
of event types. That caused a panic for `delete` events, which lack a
language.
* WIP implementation of Message refactor
* Major refactor
* Refactor scope managment to use enum
* Use Timeline type instead of String
* Clean up Receiver's use of Timeline
* Make debug output more readable
* Block statuses from blocking users
This commit fixes an issue where a status from A would be displayed on
B's public timelines even when A had B blocked (i.e., it would treat B
as though they were muted rather than blocked for the purpose of
public timelines).
* Fix bug with incorrect parsing of incomming timeline
* Disable outdated tests
* Bump version
* Read user and domain blocks from Postgres
This commit reads the blocks from pg and stores them in the User
struct; it does not yet actually filter the responses. It also does
not update the tests.
* Update tests
* Filter out toots involving blocked/muted users
* Add support for domain blocks
* Update test and bump version
Daniel Sockwell