Unfortunately we need to pull tracing-opentelemetry from git because
there hasn't been a release including the dependency bump on the other
opentelemetry crates.
tokio::spawn is a span boundary, the spawned future has no parent span.
For short futures, we simply inherit the current span with
`.in_current_span()`.
For long running futures containing a sleeping infinite loop, we don't
actually want a span on the entire task or even the entire loop body,
both would result in very long spans. Instead, we put the outermost span
(created using #[tracing::instrument] or .instrument()) around the
actual work happening after the sleep, which results in a new root span
being created after every sleep.
Previously, `Content-Disposition` was always set to `inline`, even for
HTML, which means that XSS could be easily acheived by uploading
malicious HTML and getting someone to click on the Matrix HTTP API link
for that piece of media. Now, we have an allowlist of safe values for
`Content-Type` that use `inline` while everything else defaults to
`attachment`, including HTML and SVG, which prevents XSS.
We also set the `Content-Security-Policy` header because why not.
A `set_header_or_panic` function is introduced to do what it says in
case Ruma begins providing better or worse values for the relevant
headers in the future. The safest way to handle such a case is simply
to panic.
This cache can serve invalid responses, and has an extremely low hit
rate.
It serves invalid responses because because it's only keyed off
the `since` parameter, but many of the other request parameters also
affect the response or it's side effects. This will become worse once we
implement filtering, because there will be a wider space of parameters
with different responses. This problem is fixable, but not worth it
because of the low hit rate.
The low hit rate is because normal clients will always issue the next
sync request with `since` set to the `prev_batch` value of the previous
response. The only time we expect to see multiple requests with the same
`since` is when the response is empty, but we don't cache empty
responses.
This was confirmed experimentally by logging cache hits and misses over
15 minutes with a wide variety of clients. This test was run on
matrix.computer.surgery, which has only a few active users, but a
large volume of sync traffic from many rooms. Over the test period, we
had 3 hits and 5309 misses. All hits occurred in the first minute, so I
suspect that they had something to do with client recovery from an
offline state. The clients that were connected during the test are:
- element web
- schildichat web
- iamb
- gomuks
- nheko
- fractal
- fluffychat web
- fluffychat android
- cinny web
- element android
- element X android
Fixes: #2
This change is fully automated, except the `rustfmt.toml` changes and
a few clippy directives to allow specific functions with too many lines
because they are longer now.
I would've preferred to factor these out into their own functions, but
unfortunately the inner type of the `FuturesUnordered` is unnameable.
`Box` or TAIT would help, but the former has a performance cost and the
latter doesn't exist on stable yet.
Doing this will allow `rustfmt` to collapse lines more efficiently.
Specifically, a lot of these lines fail to wrap to 80 columns without
these changes.
This makes it possible to deploy Grapevine while using a database
originally created by Conduit, including leaving the admin bot user's
localpart the same as before.
Functions using `services()` are allowed to pointlessly take `self`
because the existence of `services()` is a crime and the solution is
making the types store references to their dependencies and then going
through `self`, so just allowing the lint saves us from modifying some
code only to switch it back later. Much later. Getting rid of
`services()` will probably be an ordeal.
