The idea here is to set the parent span for incoming federation requests to the
*outgoing* span on the other end. That means that you can see (most of) the
full end-to-end flow when you have a process that includes federation requests.
However, in order not to lose information, we still want a link to the
`incoming-federation-request` span from the servlet, so we have to create
another span to do exactly that.
`start_active_span` was inconsistent as to whether it would activate the span
immediately, or wait for `scope.__enter__` to happen (it depended on whether
the current logcontext already had an associated scope). The inconsistency was
rather confusing if you were hoping to set up a couple of separate spans before
activating either.
Looking at the other implementations of opentracing `ScopeManager`s, the
intention is that it *should* be activated immediately, as the name
implies. Indeed, the idea is that you don't have to use the scope as a
contextmanager at all - you can just call `.close` on the result. Hence, our
cleanup has to happen in `.close` rather than `.__exit__`.
So, the main change here is to ensure that `start_active_span` does activate
the span, and that `scope.close()` does close the scope.
We also add some tests, which requires a `tracer` param so that we don't have
to rely on the global variable in unit tests.
* remove `start_active_span_from_request`
Instead, pull out a separate function, `span_context_from_request`, to extract
the parent span, which we can then pass into `start_active_span` as
normal. This seems to be clearer all round.
* Remove redundant tags from `incoming-federation-request`
These are all wrapped up inside a parent span generated in AsyncResource, so
there's no point duplicating all the tags that are set there.
* Leave request spans open until the request completes
It may take some time for the response to be encoded into JSON, and that JSON
to be streamed back to the client, and really we want that inside the top-level
span, so let's hand responsibility for closure to the SynapseRequest.
* opentracing logs for HTTP request events
* changelog
This commit fixes two bugs to do with decorators not instrumenting
`ReplicationEndpoint`'s `send_request` correctly. There are two
decorators on `send_request`: Prometheus' `Gauge.track_inprogress()`
and Synapse's `opentracing.trace`.
`Gauge.track_inprogress()` does not have any support for async
functions when used as a decorator. Since async functions behave like
regular functions that return coroutines, only the creation of the
coroutine was covered by the metric and none of the actual body of
`send_request`.
`Gauge.track_inprogress()` returns a regular, non-async function
wrapping `send_request`, which is the source of the next bug.
The `opentracing.trace` decorator would normally handle async functions
correctly, but since the wrapped `send_request` is a non-async function,
the decorator ends up suffering from the same issue as
`Gauge.track_inprogress()`: the opentracing span only measures the
creation of the coroutine and none of the actual function body.
Using `Gauge.track_inprogress()` as a context manager instead of a
decorator resolves both bugs.
* Trace event persistence
When we persist a batch of events, set the parent opentracing span to the that
from the request, so that we can trace all the way in.
* changelog
* When we force tracing, set a baggage item
... so that we can check again later.
* Link in both directions between persist_events spans
This adds quite a lot of OpenTracing decoration for database activity. Specifically it adds tracing at four different levels:
* emit a span for each "interaction" - ie, the top level database function that we tend to call "transaction", but isn't really, because it can end up as multiple transactions.
* emit a span while we hold a database connection open
* emit a span for each database transaction - actual actual transaction.
* emit a span for each database query.
I'm aware this might be quite a lot of overhead, but even just running it on a local Synapse it looks really interesting, and I hope the overhead can be offset just by turning down the sampling frequency and finding other ways of tracing requests of interest (eg, the `force_tracing_for_users` setting).
Part of #9744
Removes all redundant `# -*- coding: utf-8 -*-` lines from files, as python 3 automatically reads source code as utf-8 now.
`Signed-off-by: Jonathan de Jong <jonathan@automatia.nl>`
Running `dmypy run` will do a `mypy` check while spinning up a daemon
that makes rerunning `dmypy run` a lot faster.
`dmypy` doesn't support `follow_imports = silent` and has
`local_partial_types` enabled, so this PR enables those options and
fixes the issues that were newly raised. Note that `local_partial_types`
will be enabled by default in upcoming mypy releases.
- Update black version to the latest
- Run black auto formatting over the codebase
- Run autoformatting according to [`docs/code_style.md
`](80d6dc9783/docs/code_style.md)
- Update `code_style.md` docs around installing black to use the correct version
#8567 started a span for every background process. This is good as it means all Synapse code that gets run should be in a span (unless in the sentinel logging context), but it means we generate about 15x the number of spans as we did previously.
This PR attempts to reduce that number by a) not starting one for send commands to Redis, and b) deferring starting background processes until after we're sure they're necessary.
I don't really know how much this will help.
The CI appears to use the latest version of isort, which is a problem when isort gets a major version bump. Rather than try to pin the version, I've done the necessary to make isort5 happy with synapse.
This is primarily for allowing us to send those commands from workers, but for now simply allows us to ignore echoed RDATA/POSITION commands that we sent (we get echoes of sent commands when using redis). Currently we log a WARNING on the master process every time we receive an echoed RDATA.
Propagate opentracing contexts across workers
Also includes some Convenience modifications to opentracing for servlets, notably:
- Add boolean to skip the whitelisting check on inject
extract methods. - useful when injecting into carriers
locally. Otherwise we'd always have to include our
own servername and whitelist our servername
- start_active_span_from_request instead of header
- Add boolean to decide whether to extract context
from a request to a servlet
