67b24859bc
~~~
generic_server: convert connection tracking to seastar::gate
If we call server::stop() right after "server" construction, it hangs:
With the server never listening (never accepting connections and never
serving connections), nothing ever calls server::maybe_stop().
Consequently,
co_await _all_connections_stopped.get_future();
at the end of server::stop() deadlocks.
Such a server::stop() call does occur in controller::do_start_server()
[transport/controller.cc], when
- cserver->start() (sharded<cql_server>::start()) constructs a
"server"-derived object,
- start_listening_on_tcp_sockets() throws an exception before reaching
listen_on_all_shards() (for example because it fails to set up client
encryption -- certificate file is inaccessible etc.),
- the "deferred_action"
cserver->stop().get();
is invoked during cleanup.
(The cserver->stop() call exposing the connection tracking problem dates
back to commit ae4d5a60ca ("transport::controller: Shut down distributed
object on startup exception", 2020-11-25), and it's been triggerable
through the above code path since commit 6b178f9a4a
("transport/controller: split configuring sockets into separate
functions", 2024-02-05).)
Tracking live connections and connection acceptances seems like a good fit
for "seastar::gate", so rewrite the tracking with that. "seastar::gate"
can be closed (and the returned future can be waited for) without anyone
ever having entered the gate.
NOTE: this change makes it quite clear that neither server::stop() nor
server::shutdown() must be called multiple times. The permitted sequences
are:
- server::shutdown() + server::stop()
- or just server::stop().
Fixes #10305
Signed-off-by: Laszlo Ersek <laszlo.ersek@scylladb.com>
~~~
Fixes #10305.
I think we might want to backport this -- it fixes a hang-on-misconfiguration which affects `scylla-6.1.0-0.20240804.abbf0b24a60c.x86_64` minimally. Basically every release that contains commit ae4d5a60ca has a theoretical chance for the hang, and every release that contains commit 6b178f9a4a has a practical chance for the hang.
Focusing on the more practical symptom (i.e., releases containing commit 6b178f9a4a), `git tag --contains 6b178f9a4a90` gives us (ignoring candidates and release candidates):
- scylla-6.0.0
- scylla-6.0.1
- scylla-6.0.2
- scylla-6.1.0
Closes scylladb/scylladb#20212
* github.com:scylladb/scylladb:
generic_server: make server::stop() idempotent
generic_server: coroutinize server::shutdown()
generic_server: make server::shutdown() idempotent
test/generic_server: add test case
configure, cmake: sort the lists of boost unit tests
generic_server: convert connection tracking to seastar::gate
Scylla in-source tests.
For details on how to run the tests, see docs/dev/testing.md
Shared C++ utils, libraries are in lib/, for Python - pylib/
alternator - Python tests which connect to a single server and use the DynamoDB API unit, boost, raft - unit tests in C++ cql-pytest - Python tests which connect to a single server and use CQL topology* - tests that set up clusters and add/remove nodes cql - approval tests that use CQL and pre-recorded output rest_api - tests for Scylla REST API Port 9000 scylla-gdb - tests for scylla-gdb.py helper script nodetool - tests for C++ implementation of nodetool
If you can use an existing folder, consider adding your test to it. New folders should be used for new large categories/subsystems, or when the test environment is significantly different from some existing suite, e.g. you plan to start scylladb with different configuration, and you intend to add many tests and would like them to reuse an existing Scylla cluster (clusters can be reused for tests within the same folder).
To add a new folder, create a new directory, and then
copy & edit its suite.ini.