These errors are harmless and are a long-standing issue that is just now
being logged, see https://github.com/element-hq/synapse/issues/19042
```
2025-10-10 15:30:00,026 - synapse.util.metrics - 330 - ERROR - notify_interested_services-0 - Metric named cache_lru_cache__matches_user_in_member_list_example.com already registered for server example.com
2025-10-10 16:30:00.167
2025-10-10 15:30:00,026 - synapse.util.metrics - 330 - ERROR - notify_interested_services-0 - Metric named cache_lru_cache_is_interested_in_room_example.com already registered for server example.com
2025-10-10 16:30:00.167
2025-10-10 15:30:00,025 - synapse.util.metrics - 330 - ERROR - notify_interested_services-0 - Metric named cache_lru_cache_is_interested_in_event_example.com already registered for server example.com
2025-10-10 16:29:15.560
2025-10-10 15:29:15,449 - synapse.util.metrics - 330 - ERROR - notify_interested_services_ephemeral-0 - Metric named cache_lru_cache__matches_user_in_member_list_example.com already registered for server example.com
2025-10-10 16:29:15.560
2025-10-10 15:29:15,449 - synapse.util.metrics - 330 - ERROR - notify_interested_services_ephemeral-0 - Metric named cache_lru_cache_is_interested_in_room_example.com already registered for server example.com
```
Prefer the utils over raw logcontext manipulation.
Spawning from adding some logcontext debug logs in
https://github.com/element-hq/synapse/pull/18966 and since we're not
logging at the `set_current_context(...)` level (see reasoning there),
this removes some usage of `set_current_context(...)`.
Spawning from adding some logcontext debug logs in
https://github.com/element-hq/synapse/pull/18966 and since we're not
logging at the `set_current_context(...)` level (see reasoning there),
this removes some usage of `set_current_context(...)`.
Specifically, `MockClock.call_later(...)` doesn't handle logcontexts
correctly. It uses the calling logcontext as the callback context
(wrong, as the logcontext could finish before the callback finishes) and
it didn't reset back to the sentinel context before handing back to the
reactor. It was like this since it was [introduced 10+ years
ago](38da9884e7).
Instead of fixing the implementation which would just be a copy of our
normal `Clock`, we can just remove `MockClock`
### Background
As part of Element's plan to support a light form of vhosting (virtual
host) (multiple instances of Synapse in the same Python process), we're
currently diving into the details and implications of running multiple
instances of Synapse in the same Python process.
"Per-tenant logging" tracked internally by
https://github.com/element-hq/synapse-small-hosts/issues/48
### Prior art
Previously, we exposed `server_name` by providing a static logging
`MetadataFilter` that injected the values:
205d9e4fc4/synapse/config/logger.py (L216)
While this can work fine for the normal case of one Synapse instance per
Python process, this configures things globally and isn't compatible
when we try to start multiple Synapse instances because each subsequent
tenant will overwrite the previous tenant.
### What does this PR do?
We remove the `MetadataFilter` and replace it by tracking the
`server_name` in the `LoggingContext` and expose it with our existing
[`LoggingContextFilter`](205d9e4fc4/synapse/logging/context.py (L584-L622))
that we already use to expose information about the `request`.
This means that the `server_name` value follows wherever we log as
expected even when we have multiple Synapse instances running in the
same process.
### A note on logcontext
Anywhere, Synapse mistakenly uses the `sentinel` logcontext to log
something, we won't know which server sent the log. We've been fixing up
`sentinel` logcontext usage as tracked by
https://github.com/element-hq/synapse/issues/18905
Any further `sentinel` logcontext usage we find in the future can be
fixed piecemeal as normal.
d2a966f922/docs/log_contexts.md (L71-L81)
### Testing strategy
1. Adjust your logging config to include `%(server_name)s` in the format
```yaml
formatters:
precise:
format: '%(asctime)s - %(server_name)s - %(name)s - %(lineno)d -
%(levelname)s - %(request)s - %(message)s'
```
1. Start Synapse: `poetry run synapse_homeserver --config-path
homeserver.yaml`
1. Make some requests (`curl
http://localhost:8008/_matrix/client/versions`, etc)
1. Open the homeserver logs and notice the `server_name` in the logs as
expected. `unknown_server_from_sentinel_context` is expected for the
`sentinel` logcontext (things outside of Synapse).
Part of https://github.com/element-hq/synapse/issues/18905
Lints for ensuring we use `Clock.call_later` instead of
`reactor.callLater`, etc are coming in
https://github.com/element-hq/synapse/pull/18944
### Testing strategy
1. Configure Synapse to log at the `DEBUG` level
1. Start Synapse: `poetry run synapse_homeserver --config-path
homeserver.yaml`
1. Wait 10 seconds for the [database profiling
loop](9cc4001778/synapse/storage/database.py (L711))
to execute
1. Notice the logcontext being used for the `Total database time` log
line
Before (`sentinel`):
```
2025-09-10 16:36:58,651 - synapse.storage.TIME - 707 - DEBUG - sentinel - Total database time: 0.646% {room_forgetter_stream_pos(2): 0.131%, reap_monthly_active_users(1): 0.083%, get_device_change_last_converted_pos(1): 0.078%}
```
After (`looping_call`):
```
2025-09-10 16:36:58,651 - synapse.storage.TIME - 707 - DEBUG - looping_call - Total database time: 0.646% {room_forgetter_stream_pos(2): 0.131%, reap_monthly_active_users(1): 0.083%, get_device_change_last_converted_pos(1): 0.078%}
```
Introduce `Clock.add_system_event_trigger(...)` to wrap system event
callback code in a logcontext, ensuring we can identify which server
generated the logs.
Background:
> Ideally, nothing from the Synapse homeserver would be logged against the `sentinel`
> logcontext as we want to know which server the logs came from. In practice, this is not
> always the case yet especially outside of request handling.
>
> Global things outside of Synapse (e.g. Twisted reactor code) should run in the
> `sentinel` logcontext. It's only when it calls into application code that a logcontext
> gets activated. This means the reactor should be started in the `sentinel` logcontext,
> and any time an awaitable yields control back to the reactor, it should reset the
> logcontext to be the `sentinel` logcontext. This is important to avoid leaking the
> current logcontext to the reactor (which would then get picked up and associated with
> the next thing the reactor does).
>
> *-- `docs/log_contexts.md`
Also adds a lint to prefer `Clock.add_system_event_trigger(...)` over
`reactor.addSystemEventTrigger(...)`
Part of https://github.com/element-hq/synapse/issues/18905
Introduce `Clock.call_when_running(...)` to wrap startup code in a
logcontext, ensuring we can identify which server generated the logs.
Background:
> Ideally, nothing from the Synapse homeserver would be logged against the `sentinel`
> logcontext as we want to know which server the logs came from. In practice, this is not
> always the case yet especially outside of request handling.
>
> Global things outside of Synapse (e.g. Twisted reactor code) should run in the
> `sentinel` logcontext. It's only when it calls into application code that a logcontext
> gets activated. This means the reactor should be started in the `sentinel` logcontext,
> and any time an awaitable yields control back to the reactor, it should reset the
> logcontext to be the `sentinel` logcontext. This is important to avoid leaking the
> current logcontext to the reactor (which would then get picked up and associated with
> the next thing the reactor does).
>
> *-- `docs/log_contexts.md`
Also adds a lint to prefer `Clock.call_when_running(...)` over
`reactor.callWhenRunning(...)`
Part of https://github.com/element-hq/synapse/issues/18905
Remove `sentinel` logcontext where we log in `setup`, `start`, and exit.
Instead of having one giant PR that removes all places we use `sentinel`
logcontext, I've decided to tackle this more piece-meal. This PR covers
the parts if you just startup Synapse and exit it with no requests or
activity going on in between.
Part of https://github.com/element-hq/synapse/issues/18905 (Remove
`sentinel` logcontext where we log in Synapse)
Prerequisite for https://github.com/element-hq/synapse/pull/18868.
Logging with the `sentinel` logcontext means we won't know which server
the log came from.
### Why
9cc4001778/docs/log_contexts.md (L71-L81)
(docs updated in https://github.com/element-hq/synapse/pull/18900)
### Testing strategy
1. Run Synapse normally and with `daemonize: true`: `poetry run
synapse_homeserver --config-path homeserver.yaml`
1. Execute some requests
1. Shutdown the server
1. Look for any bad log entries in your homeserver logs:
- `Expected logging context sentinel but found main`
- `Expected logging context main was lost`
- `Expected previous context`
- `utime went backwards!`/`stime went backwards!`
- `Called stop on logcontext POST-0 without recording a start rusage`
1. Look for any logs coming from the `sentinel` context
With these changes, you should only see the following logs (not from
Synapse) using the `sentinel` context if you start up Synapse and exit:
`homeserver.log`
```
2025-09-10 14:45:39,924 - asyncio - 64 - DEBUG - sentinel - Using selector: EpollSelector
2025-09-10 14:45:40,562 - twisted - 281 - INFO - sentinel - Received SIGINT, shutting down.
2025-09-10 14:45:40,562 - twisted - 281 - INFO - sentinel - (TCP Port 9322 Closed)
2025-09-10 14:45:40,563 - twisted - 281 - INFO - sentinel - (TCP Port 8008 Closed)
2025-09-10 14:45:40,563 - twisted - 281 - INFO - sentinel - (TCP Port 9093 Closed)
2025-09-10 14:45:40,564 - twisted - 281 - INFO - sentinel - Main loop terminated.
```
This PR reverts https://github.com/element-hq/synapse/pull/18751
### Why revert?
@reivilibre
[found](https://matrix.to/#/!vcyiEtMVHIhWXcJAfl:sw1v.org/$u9OEmMxaFYUzWHhCk1A_r50Y0aGrtKEhepF7WxWJkUA?via=matrix.org&via=node.marinchik.ink&via=element.io)
that our CI was failing in bizarre ways (thanks for stepping up to dive
into this 🙇). Examples:
- `twisted.internet.error.ProcessTerminated: A process has ended with a
probable error condition: process ended by signal 9.`
- `twisted.internet.error.ProcessTerminated: A process has ended with a
probable error condition: process ended by signal 15.`
<details>
<summary>More detailed part of the log</summary>
https://github.com/element-hq/synapse/actions/runs/16758038107/job/47500520633#step:9:6809
```
tests.util.test_wheel_timer.WheelTimerTestCase.test_single_insert_fetch
===============================================================================
Error:
Traceback (most recent call last):
File "/home/runner/.cache/pypoetry/virtualenvs/matrix-synapse-pswDeSvb-py3.9/lib/python3.9/site-packages/twisted/trial/_dist/disttrial.py", line 371, in task
await worker.run(case, result)
File "/home/runner/.cache/pypoetry/virtualenvs/matrix-synapse-pswDeSvb-py3.9/lib/python3.9/site-packages/twisted/trial/_dist/worker.py", line 305, in run
return await self.callRemote(workercommands.Run, testCase=testCaseId) # type: ignore[no-any-return]
File "/home/runner/.cache/pypoetry/virtualenvs/matrix-synapse-pswDeSvb-py3.9/lib/python3.9/site-packages/twisted/internet/defer.py", line 1187, in __iter__
yield self
File "/home/runner/.cache/pypoetry/virtualenvs/matrix-synapse-pswDeSvb-py3.9/lib/python3.9/site-packages/twisted/internet/defer.py", line 1092, in _runCallbacks
current.result = callback( # type: ignore[misc]
File "/home/runner/.cache/pypoetry/virtualenvs/matrix-synapse-pswDeSvb-py3.9/lib/python3.9/site-packages/twisted/protocols/amp.py", line 1968, in _massageError
error.trap(RemoteAmpError)
File "/home/runner/.cache/pypoetry/virtualenvs/matrix-synapse-pswDeSvb-py3.9/lib/python3.9/site-packages/twisted/python/failure.py", line 431, in trap
self.raiseException()
File "/home/runner/.cache/pypoetry/virtualenvs/matrix-synapse-pswDeSvb-py3.9/lib/python3.9/site-packages/twisted/python/failure.py", line 455, in raiseException
raise self.value.with_traceback(self.tb)
twisted.internet.error.ProcessTerminated: A process has ended with a probable error condition: process ended by signal 9.
tests.util.test_macaroons.MacaroonGeneratorTestCase.test_guest_access_token
-------------------------------------------------------------------------------
Ran 4325 tests in 669.321s
FAILED (skips=159, errors=62, successes=4108)
while calling from thread
Traceback (most recent call last):
File "/home/runner/.cache/pypoetry/virtualenvs/matrix-synapse-pswDeSvb-py3.9/lib/python3.9/site-packages/twisted/internet/base.py", line 1064, in runUntilCurrent
f(*a, **kw)
File "/home/runner/.cache/pypoetry/virtualenvs/matrix-synapse-pswDeSvb-py3.9/lib/python3.9/site-packages/twisted/internet/base.py", line 790, in stop
raise error.ReactorNotRunning("Can't stop reactor that isn't running.")
twisted.internet.error.ReactorNotRunning: Can't stop reactor that isn't running.
joining disttrial worker #0 failed
Traceback (most recent call last):
File "/home/runner/.cache/pypoetry/virtualenvs/matrix-synapse-pswDeSvb-py3.9/lib/python3.9/site-packages/twisted/internet/defer.py", line 1853, in _inlineCallbacks
result = context.run(
File "/home/runner/.cache/pypoetry/virtualenvs/matrix-synapse-pswDeSvb-py3.9/lib/python3.9/site-packages/twisted/python/failure.py", line 467, in throwExceptionIntoGenerator
return g.throw(self.value.with_traceback(self.tb))
File "/home/runner/.cache/pypoetry/virtualenvs/matrix-synapse-pswDeSvb-py3.9/lib/python3.9/site-packages/twisted/trial/_dist/worker.py", line 406, in exit
await endDeferred
File "/home/runner/.cache/pypoetry/virtualenvs/matrix-synapse-pswDeSvb-py3.9/lib/python3.9/site-packages/twisted/internet/defer.py", line 1187, in __iter__
yield self
twisted.internet.error.ProcessTerminated: A process has ended with a probable error condition: process ended by signal 15.
```
</details>
With more debugging (thanks @devonh for also stepping in as maintainer),
we were finding that the CI was consistently failing at
`test_exposed_to_prometheus` which was a bit of smoke because of all of
the [metrics
changes](https://github.com/element-hq/synapse/issues/18592) that were
merged recently.
Locally, although I wasn't able to reproduce the bizarre errors, I could
easily see increased memory usage (~20GB vs ~2GB) and the
`test_exposed_to_prometheus` test taking a while to complete when
running a full test run (`SYNAPSE_TEST_LOG_LEVEL=INFO poetry run trial
tests`).
<img width="1485" height="78" alt="Lots of memory usage"
src="https://github.com/user-attachments/assets/811e2a96-75e5-4a3c-966c-00dc0512cea9"
/>
After updating `test_exposed_to_prometheus` to dump the
`latest_metrics_response = generate_latest(REGISTRY)`, I could see that
it's a massive 3.2GB response. Inspecting the contents, we can see 4.1M
(4,137,123) entries for just
`synapse_background_update_status{server_name="test"} 3.0` which is a
`LaterGauge`. I don't think we have 4.1M test cases so it's also unclear
why we end up with so many samples but it does make sense that we do see
a lot of duplicates because each `HomeserverTestCase` will create a
homeserver for each test case that will `LaterGauge.register_hook(...)`
(part of the https://github.com/element-hq/synapse/pull/18751 changes).
`tests/storage/databases/main/test_metrics.py`
```python
latest_metrics_response = generate_latest(REGISTRY)
with open("/tmp/synapse-test-metrics", "wb") as f:
f.write(latest_metrics_response)
```
After reverting the https://github.com/element-hq/synapse/pull/18751
changes, running the full test suite locally doesn't result in memory
spikes and seems to run normally.
### Dev notes
Discussion in the
[`#synapse-dev:matrix.org`](https://matrix.to/#/!vcyiEtMVHIhWXcJAfl:sw1v.org/$vkMATs04yqZggVVd6Noop5nU8M2DVoTkrAWshw7u1-w?via=matrix.org&via=node.marinchik.ink&via=element.io)
room.
### Pull Request Checklist
<!-- Please read
https://element-hq.github.io/synapse/latest/development/contributing_guide.html
before submitting your pull request -->
* [x] Pull request is based on the develop branch
* [ ] Pull request includes a [changelog
file](https://element-hq.github.io/synapse/latest/development/contributing_guide.html#changelog).
The entry should:
- Be a short description of your change which makes sense to users.
"Fixed a bug that prevented receiving messages from other servers."
instead of "Moved X method from `EventStore` to `EventWorkerStore`.".
- Use markdown where necessary, mostly for `code blocks`.
- End with either a period (.) or an exclamation mark (!).
- Start with a capital letter.
- Feel free to credit yourself, by adding a sentence "Contributed by
@github_username." or "Contributed by [Your Name]." to the end of the
entry.
* [ ] [Code
style](https://element-hq.github.io/synapse/latest/code_style.html) is
correct (run the
[linters](https://element-hq.github.io/synapse/latest/development/contributing_guide.html#run-the-linters))
Fix `LaterGauge` metrics to collect from all servers
Follow-up to https://github.com/element-hq/synapse/pull/18714
Previously, our `LaterGauge` metrics did include the `server_name` label
as expected but we were only seeing the last server being reported in
some cases. Any `LaterGauge` that we were creating multiple times was
only reporting the last instance.
This PR updates all `LaterGauge` to be created once and then we use
`LaterGauge.register_hook(...)` to add in the metric callback as before.
This works now because we store a list of callbacks instead of just one.
I noticed this problem thanks to some [tests in the Synapse Pro for
Small Hosts](https://github.com/element-hq/synapse-small-hosts/pull/173)
repo that sanity check all metrics to ensure that we can see each metric
includes data from multiple servers.
### Testing strategy
1. This is only noticeable when you run multiple Synapse instances in
the same process.
1. TODO
(see test that was added)
### Dev notes
Previous non-global `LaterGauge`:
```
synapse_federation_send_queue_xxx
synapse_federation_transaction_queue_pending_destinations
synapse_federation_transaction_queue_pending_pdus
synapse_federation_transaction_queue_pending_edus
synapse_handlers_presence_user_to_current_state_size
synapse_handlers_presence_wheel_timer_size
synapse_notifier_listeners
synapse_notifier_rooms
synapse_notifier_users
synapse_replication_tcp_resource_total_connections
synapse_replication_tcp_command_queue
synapse_background_update_status
synapse_federation_known_servers
synapse_scheduler_running_tasks
```
### Pull Request Checklist
<!-- Please read
https://element-hq.github.io/synapse/latest/development/contributing_guide.html
before submitting your pull request -->
* [x] Pull request is based on the develop branch
* [x] Pull request includes a [changelog
file](https://element-hq.github.io/synapse/latest/development/contributing_guide.html#changelog).
The entry should:
- Be a short description of your change which makes sense to users.
"Fixed a bug that prevented receiving messages from other servers."
instead of "Moved X method from `EventStore` to `EventWorkerStore`.".
- Use markdown where necessary, mostly for `code blocks`.
- End with either a period (.) or an exclamation mark (!).
- Start with a capital letter.
- Feel free to credit yourself, by adding a sentence "Contributed by
@github_username." or "Contributed by [Your Name]." to the end of the
entry.
* [x] [Code
style](https://element-hq.github.io/synapse/latest/code_style.html) is
correct (run the
[linters](https://element-hq.github.io/synapse/latest/development/contributing_guide.html#run-the-linters))
Follow-up to https://github.com/element-hq/synapse/pull/18604
Previously, our cache metrics did include the `server_name` label as
expected but we were only seeing the last server being reported. This
was caused because we would
`CACHE_METRIC_REGISTRY.register_hook(metric_name, metric.collect)` where
the `metric_name` only took into account the cache name so it would be
overwritten every time we spawn a new server.
This PR updates the register logic to include the `server_name` so we
have a hook for every cache on every server as expected.
I noticed this problem thanks to some [tests in the Synapse Pro for
Small Hosts](https://github.com/element-hq/synapse-small-hosts/pull/173)
repo that sanity check all metrics to ensure that we can see each metric
includes data from multiple servers.
Bulk refactor `Histogram` metrics to be homeserver-scoped. We also add
lints to make sure that new `Histogram` metrics don't sneak in without
using the `server_name` label (`SERVER_NAME_LABEL`).
Part of https://github.com/element-hq/synapse/issues/18592
### Testing strategy
1. Add the `metrics` listener in your `homeserver.yaml`
```yaml
listeners:
# This is just showing how to configure metrics either way
#
# `http` `metrics` resource
- port: 9322
type: http
bind_addresses: ['127.0.0.1']
resources:
- names: [metrics]
compress: false
# `metrics` listener
- port: 9323
type: metrics
bind_addresses: ['127.0.0.1']
```
1. Start the homeserver: `poetry run synapse_homeserver --config-path
homeserver.yaml`
1. Fetch `http://localhost:9322/_synapse/metrics` and/or
`http://localhost:9323/metrics`
1. Observe response includes the TODO metrics with the `server_name`
label
### Todo
- [x] Wait for https://github.com/element-hq/synapse/pull/18656 to merge
### Dev notes
```
LoggingDatabaseConnection
make_conn
make_pool
make_fake_db_pool
```
### Pull Request Checklist
<!-- Please read
https://element-hq.github.io/synapse/latest/development/contributing_guide.html
before submitting your pull request -->
* [x] Pull request is based on the develop branch
* [x] Pull request includes a [changelog
file](https://element-hq.github.io/synapse/latest/development/contributing_guide.html#changelog).
The entry should:
- Be a short description of your change which makes sense to users.
"Fixed a bug that prevented receiving messages from other servers."
instead of "Moved X method from `EventStore` to `EventWorkerStore`.".
- Use markdown where necessary, mostly for `code blocks`.
- End with either a period (.) or an exclamation mark (!).
- Start with a capital letter.
- Feel free to credit yourself, by adding a sentence "Contributed by
@github_username." or "Contributed by [Your Name]." to the end of the
entry.
* [x] [Code
style](https://element-hq.github.io/synapse/latest/code_style.html) is
correct (run the
[linters](https://element-hq.github.io/synapse/latest/development/contributing_guide.html#run-the-linters))
Bulk refactor `Gauge` metrics to be homeserver-scoped. We also add lints
to make sure that new `Gauge` metrics don't sneak in without using the
`server_name` label (`SERVER_NAME_LABEL`).
Part of https://github.com/element-hq/synapse/issues/18592
### Testing strategy
1. Add the `metrics` listener in your `homeserver.yaml`
```yaml
listeners:
# This is just showing how to configure metrics either way
#
# `http` `metrics` resource
- port: 9322
type: http
bind_addresses: ['127.0.0.1']
resources:
- names: [metrics]
compress: false
# `metrics` listener
- port: 9323
type: metrics
bind_addresses: ['127.0.0.1']
```
1. Start the homeserver: `poetry run synapse_homeserver --config-path
homeserver.yaml`
1. Fetch `http://localhost:9322/_synapse/metrics` and/or
`http://localhost:9323/metrics`
1. Observe response includes the TODO metrics with the `server_name`
label
### Pull Request Checklist
<!-- Please read
https://element-hq.github.io/synapse/latest/development/contributing_guide.html
before submitting your pull request -->
* [x] Pull request is based on the develop branch
* [x] Pull request includes a [changelog
file](https://element-hq.github.io/synapse/latest/development/contributing_guide.html#changelog).
The entry should:
- Be a short description of your change which makes sense to users.
"Fixed a bug that prevented receiving messages from other servers."
instead of "Moved X method from `EventStore` to `EventWorkerStore`.".
- Use markdown where necessary, mostly for `code blocks`.
- End with either a period (.) or an exclamation mark (!).
- Start with a capital letter.
- Feel free to credit yourself, by adding a sentence "Contributed by
@github_username." or "Contributed by [Your Name]." to the end of the
entry.
* [x] [Code
style](https://element-hq.github.io/synapse/latest/code_style.html) is
correct (run the
[linters](https://element-hq.github.io/synapse/latest/development/contributing_guide.html#run-the-linters))
Bulk refactor `Counter` metrics to be homeserver-scoped. We also add
lints to make sure that new `Counter` metrics don't sneak in without
using the `server_name` label (`SERVER_NAME_LABEL`).
All of the "Fill in" commits are just bulk refactor.
Part of https://github.com/element-hq/synapse/issues/18592
### Testing strategy
1. Add the `metrics` listener in your `homeserver.yaml`
```yaml
listeners:
# This is just showing how to configure metrics either way
#
# `http` `metrics` resource
- port: 9322
type: http
bind_addresses: ['127.0.0.1']
resources:
- names: [metrics]
compress: false
# `metrics` listener
- port: 9323
type: metrics
bind_addresses: ['127.0.0.1']
```
1. Start the homeserver: `poetry run synapse_homeserver --config-path
homeserver.yaml`
1. Fetch `http://localhost:9322/_synapse/metrics` and/or
`http://localhost:9323/metrics`
1. Observe response includes the `synapse_user_registrations_total`,
`synapse_http_server_response_count_total`, etc metrics with the
`server_name` label
Part of https://github.com/element-hq/synapse/issues/18592
Separated out of https://github.com/element-hq/synapse/pull/18656
because it's a bigger, unique piece of the refactor
### Testing strategy
1. Add the `metrics` listener in your `homeserver.yaml`
```yaml
listeners:
# This is just showing how to configure metrics either way
#
# `http` `metrics` resource
- port: 9322
type: http
bind_addresses: ['127.0.0.1']
resources:
- names: [metrics]
compress: false
# `metrics` listener
- port: 9323
type: metrics
bind_addresses: ['127.0.0.1']
```
1. Start the homeserver: `poetry run synapse_homeserver --config-path
homeserver.yaml`
1. Fetch `http://localhost:9322/_synapse/metrics` and/or
`http://localhost:9323/metrics`
1. Observe response includes the background processs metrics
(`synapse_background_process_start_count`,
`synapse_background_process_db_txn_count_total`, etc) with the
`server_name` label
Refactor `Measure` block metrics to be homeserver-scoped (add
`server_name` label to block metrics).
Part of https://github.com/element-hq/synapse/issues/18592
### Testing strategy
#### See behavior of previous `metrics` listener
1. Add the `metrics` listener in your `homeserver.yaml`
```yaml
listeners:
- port: 9323
type: metrics
bind_addresses: ['127.0.0.1']
```
1. Start the homeserver: `poetry run synapse_homeserver --config-path
homeserver.yaml`
1. Fetch `http://localhost:9323/metrics`
1. Observe response includes the block metrics
(`synapse_util_metrics_block_count`,
`synapse_util_metrics_block_in_flight`, etc)
#### See behavior of the `http` `metrics` resource
1. Add the `metrics` resource to a new or existing `http` listeners in
your `homeserver.yaml`
```yaml
listeners:
- port: 9322
type: http
bind_addresses: ['127.0.0.1']
resources:
- names: [metrics]
compress: false
```
1. Start the homeserver: `poetry run synapse_homeserver --config-path
homeserver.yaml`
1. Fetch `http://localhost:9322/_synapse/metrics` (it's just a `GET`
request so you can even do in the browser)
1. Observe response includes the block metrics
(`synapse_util_metrics_block_count`,
`synapse_util_metrics_block_in_flight`, etc)
This implements
https://github.com/matrix-org/matrix-spec-proposals/pull/3765 which is
already merged and, therefore, can use stable identifiers.
For `/publicRooms` and `/hierarchy`, the topic is read from the
eponymous field of the `current_state_events` table. Rather than
introduce further columns in this table, I changed the insertion /
update logic to write the plain-text topic from the rich topic into the
existing field. This will not take effect for existing rooms unless
their topic is changed. However, existing rooms shouldn't have rich
topics to begin with.
Similarly, for server-side search, I changed the insertion logic of the
`event_search` table to prefer the value from the rich topic. Again,
existing events shouldn't have rich topics and, therefore, don't need to
be migrated in the table.
Spec doc: https://spec.matrix.org/v1.15/client-server-api/#mroomtopic
Part of supporting Matrix v1.15:
https://spec.matrix.org/v1.15/client-server-api/#mroomtopic
Signed-off-by: Johannes Marbach <n0-0ne+github@mailbox.org>
Co-authored-by: Eric Eastwood <erice@element.io>
This was correctly handled for the "fallback" case where the background
updates hadn't finished
---------
Co-authored-by: Eric Eastwood <erice@element.io>
This can be reviewed commit by commit.
This enables the `flake8-logging` and `flake8-logging-format` rules in
Ruff, as well as logging exception stack traces in a few places where it
makes sense
- https://docs.astral.sh/ruff/rules/#flake8-logging-log
- https://docs.astral.sh/ruff/rules/#flake8-logging-format-g
### Linting to avoid pre-formatting log messages
See [`adamchainz/flake8-logging` -> *LOG011 avoid pre-formatting log
messages*](152db2f167/README.rst (log011-avoid-pre-formatting-log-messages))
Practically, this means prefer placeholders (`%s`) over f-strings for
logging.
This is because placeholders are passed as args to loggers, so they can
do special handling of them.
For example, Sentry will record the args separately in their logging
integration:
c15b390dfe/sentry_sdk/integrations/logging.py (L280-L284)
One theoretical small perf benefit is that log levels that aren't
enabled won't get formatted, so it doesn't unnecessarily create
formatted strings
This is particularly a problem in a state reset scenario where the membership
might change without a corresponding event.
This PR is targeting a scenario where a state reset happens which causes
room membership to change. Previously, the cache would just hold onto
stale data and now we properly bust the cache in this scenario.
We have a few tests for these scenarios which you can see are now fixed
because we can remove the `FIXME` where we were previously manually
busting the cache in the test itself.
This is a general Synapse thing so by it's nature it helps out Sliding
Sync.
Fix https://github.com/element-hq/synapse/issues/17368
Prerequisite for https://github.com/element-hq/synapse/issues/17929
---
Match when are busting `_curr_state_delta_stream_cache`
`defer.returnValue` was only needed in Python 2; in Python 3, a simple
`return` is fine.
`twisted.internet.defer.returnValue` is deprecated as of Twisted 24.7.0.
Most uses of `returnValue` in synapse were removed a while back; this
cleans up some remaining bits.
Currently, when a new scheduled task is added and its scheduled time has
already passed, we set it to ACTIVE. This is problematic, because it
means it will jump the queue ahead of all other SCHEDULED tasks;
furthermore, if the Synapse process gets restarted, it will jump ahead
of any ACTIVE tasks which have been started but are taking a while to
run.
Instead, we leave it set to SCHEDULED, but kick off a call to
`_launch_scheduled_tasks`, which will decide if we actually have
capacity to start a new task, and start the newly-added task if so.
When entries insert in the end of timer queue, then unnecessary entry
inserted (with duplicated key).
This can lead to some timeouts expired early and consume memory.
The main change here is to add a helper function
`gather_optional_coroutines`, which works in a similar way as
`yieldable_gather_results` but takes a set of coroutines rather than a
function
There is a bug with the `StreamChangeCache` where it would incorrectly
return that all entities had changed if asked for entities changed
*since* the earliest stream position.
Note that for streams we use the inequalities: `$min_stream_id <
stream_id <= $max_stream_id`, i.e. when we ask the stream change cache
for all things that have changed since `$stream_id` we don't care for
events that happened *at* `$stream_id`.
Specifically: `_earliest_known_stream_pos` is the position at which we
know that we'll have entries for all changes since that point, we can
use the cache for any stream IDs that equal
`_earliest_known_stream_pos`.
`_earliest_known_stream_pos` is set in three places:
- On startup we set it either to:
- the current maximum stream ID, with not prefilled values; or
- the minimum of the latest N values we pulled from the DB
- When we evict items from the bottom, we set it to the stream ID of the
evicted items.
This was changed in https://github.com/matrix-org/synapse/pull/14435,
but I think we were overly conservative there.
---------
Co-authored-by: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>
I thought ruff check would also format, but it doesn't.
This runs ruff format in CI and dev scripts. The first commit is just a
run of `ruff format .` in the root directory.
Follow on from #17558
Basically, we want to reduce the number of threads we want to use at a
time, i.e. reduce the number of threads that are paused/blocked. We do
this by returning from the thread when the consumer pauses the producer,
rather than pausing in the thread.
---------
Co-authored-by: Andrew Morgan <1342360+anoadragon453@users.noreply.github.com>
