Change default port if provided in new cluster

[michaelraney]

Currently, when creating a cluster, the contact points can contain the port as well. Currently this does not change the port when a new cluster is configured, causing timeout issues to peers. This especially impacting when using TLS which is using 9142 instead of 9042. If user does not set Cluster.Port connection to peers will fail. Traditionally, cassandra drivers do not support connecting to nodes on different cql ports. All nodes must have the same cql port. The result is users may end up connected only to provided seeds initial host without connecting to peers. This pull request adds port assignment to NewCluster by extracting it from the host string if provided

Previously when using the following connection, initial control connection will connect to provided host with 9142. Discovered peers will connect to 9042 the default.

cluster := gocql.NewCluster("cassandra.us-east-1.amazonaws.com:9142")

User must add the port after to fix.

cluster := gocql.NewCluster("cassandra.us-east-1.amazonaws.com:9142")
cluster.Port = 9142

This change will allow user to create connection string and the default host will be the one provided if found. Eliminating simple mistake.

cluster := gocql.NewCluster("cassandra.us-east-1.amazonaws.com:9142")

[martin-sucha]

Thanks for the pull request!

Cassandra 4.0 supports different ports per node (see 8f058c6). However, with Cassandra 4.0 and later, the ClusterConfig.Port will be ignored (instead gocql will use the port from system.peers_v2) so the change should be safe with Cassandra 4.0.

Could this change break something? What should happen if the seeds have different ports? For example shouldn't gocql.NewCluster("hostname1:9142", "hostname2") use 9042 instead of 9142? Shouldn't we try to infer the port only if all the ports are the same?

In any case, please add an entry to the AUTHORS file.