Add the ability to iterate over the list of connections in a "gentle"
manner, i.e. -- preempting the loop when required.
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Instead of lengthy blurbs, switch to single-line, machine-readable
standardized (https://spdx.dev) license identifiers. The Linux kernel
switched long ago, so there is strong precedent.
Three cases are handled: AGPL-only, Apache-only, and dual licensed.
For the latter case, I chose (AGPL-3.0-or-later and Apache-2.0),
reasoning that our changes are extensive enough to apply our license.
The changes we applied mechanically with a script, except to
licenses/README.md.
Closes#9937
There's at least one tiny race in generic_server code. The trailing
.handle_exception after the conn->process() captures this, but since the
whole continuation chain happens in the background, that this can be
released thus causing the whole lambda to execute on freed generic_server
instance. This, in turn, is not nice because captured this is used to get
a _logger from.
The fix is based on the observation that all connections pin the server
in memory until all of them (connections) are destructed. Said that, to
keep the server alive in the aforementioned lambda it's enough to make
sure the conn variable (it's lw_shared_ptr on the connection) is alive in
it. Not to generate a bunch of tiny continuations with identical set of
captures -- tail the single .then_wrapped() one and do whatever is needed
to wrap up the connection processing in it.
tests: unit(dev)
fixes: #9316
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
Message-Id: <20211115105818.11348-1-xemul@scylladb.com>
After subscription management was moved onto controller level
a bunch of code can be dropped:
- passing migration notifier beyond controller
- event_notifier's _stopped bit
- event_notifier .stop() method
- event_notifier empty constructor and destrictor
- generic_server's on_stop virtual method
Signed-off-by: Pavel Emelyanov <xemul@scylladb.com>
The cql_server and redis_server share the same ancestor of do_accepts().
Let's pull up the cql_server version of do_accept() (that has more
functionality) to generic_server::server and use it in the redis_server
too.
Pull up the cql_server process() to base class and convert redis_server
to use it.
Please note that this fixes EPIPE and connection reset issue in the
Redis server, which was fixed in the CQL server in commit 1a8630e6a
("transport: silence "broken pipe" and "connection reset by peer"
errors").
The cql_server and redis_server classes have a maybe_idle() method,
which sets the _all_connections_stopped promise if server wants to stop
and can be stopped. Pull up the duplicated code to
generic_server::server class.
This patch moves the duplicated connection::shutdown() method to to a
new generic_server::connection base class that is now inherited by
cql_server and redis_server.
