In case of an error, we want to see the contents of the system.clients
table to have a better understanding of what happened - whether the
row(s) are really missing or maybe they are there, but 1 digit doesn't
match or the row is half-written.
We'll therefore query for the whole table on the CQL side, and then
filter out the rows we want to later proceed with on the python side.
This way we can dump the contents of the whole system.clients table if
something goes south.
`test_proxy_protocol_port_preserved_in_system_clients` failed because it
didn't see the just created connection in system.clients immediately. The
last lines of the stacktrace are:
```
# Complete CQL handshake
await do_cql_handshake(reader, writer)
# Now query system.clients using the driver to see our connection
cql = manager.get_cql()
rows = list(cql.execute(
f"SELECT address, port FROM system.clients WHERE address = '{fake_src_addr}' ALLOW FILTERING"
))
# We should find our connection with the fake source address and port
> assert len(rows) > 0, f"Expected to find connection from {fake_src_addr} in system.clients"
E AssertionError: Expected to find connection from 203.0.113.200 in system.clients
E assert 0 > 0
E + where 0 = len([])
```
Explanation: we first await for the hand-made connection to be completed,
then, via another connection, we're querying system.clients, and we don't
get this hand-made connection in the resultset.
The solution is to replace the bare cql.execute() calls with await wait_for_results(), a helper
that polls via cql.run_async() until the expected row count is reached
(30 s timeout, 100 ms period).
Fixes: SCYLLADB-819
It was observed twice that the test times out in debug mode.
Fix by increasing the timeout.
The test never expects a timeout, so increasing it won't increase
the test duration.
Fixes#28028Closesscylladb/scylladb#28272
Test that the new configuration options work and that we can
connect to them. Use direct connections with an inline implementation
of the proxy protocol and the CQL native protocol, since we want
to maintain direct control over the source port number (for shard-aware
ports). Also test we land on the expected shard.