Add QueryTypeFilter compatibility to CassandraSinkCluster

[justinweng-instaclustr]

This PR first adds a new integration test to reproduce the incompatibility problem between QueryTypeFilter and CassandraSinkCluster. This new test places a QueryTypeFilter in front of CassandraSinkCluster in the transform chain which causes the error below (ref: example failed CI test). The problem here is that QueryTypeFilter replaces the filtered request with a Frame::Dummy which doesn't have a stream_id, and passes the dummy frame to the downstream CassandraSinkCluster which then runs x.stream_id().unwrap(), leading to the error of calling Option::unwrap() on the None value.

shotover   23:46:34.417319Z PANIC panicked at shotover/src/transforms/cassandra/sink_cluster/connection.rs:30:59:
called `Option::unwrap()` on a `None` value
   0: __rustc::rust_begin_unwind
             at /rustc/4a4ef493e3a1488c6e321570238084b38948f6db/library/std/src/panicking.rs:689:5
   1: core::panicking::panic_fmt
             at /rustc/4a4ef493e3a1488c6e321570238084b38948f6db/library/core/src/panicking.rs:80:14
   2: core::panicking::panic
             at /rustc/4a4ef493e3a1488c6e321570238084b38948f6db/library/core/src/panicking.rs:150:5
   3: core::option::unwrap_failed
             at /rustc/4a4ef493e3a1488c6e321570238084b38948f6db/library/core/src/option.rs:2199:5
   4: core::option::Option<T>::unwrap
             at /rustc/4a4ef493e3a1488c6e321570238084b38948f6db/library/core/src/option.rs:1016:21
      shotover::transforms::cassandra::sink_cluster::connection::CassandraConnection::send::{{closure}}
             at /home/runner/work/shotover-proxy/shotover-proxy/shotover/src/transforms/cassandra/sink_cluster/connection.rs:30:59

To resolve this incompatibility issue, extra logic for handling dummy message is added to [‎shotover/src/transforms/cassandra/sink_cluster/connection.rs and ‎shotover/src/transforms/cassandra/sink_cluster/mod.rs, allowing the new integration test to pass.

Additionally, the Cassandra error type for filtered responses is changed from ErrorType::Server to ErrorType::Invalid because the Datastax C++ driver defuncts the connection on Server errors which breaks subsequent queries (other drivers handle server errors more gracefully and are fine).

Specifically, the C++ driver produced this warning (WARN datastax::internal::core::RequestExecution::on_error_response: Received server error 'Message was filtered out by shotover' from host 127.0.0.1. Defuncting the connection...) in the integration test, which then led to the error thread 'cassandra_int_tests::cluster_single_rack_v4_query_type_filter::case_1_cpp' (5539) panicked at test-helpers/src/connection/cassandra/connection/cpp.rs:164:25: Unexpected cassandra_cpp error: Cassandra error LIB_NO_HOSTS_AVAILABLE: All hosts in current policy attempted and were either unavailable or failed because the driver regarded nodes as down after defuncting the connection. Example CI run here.

A filtered query is a rejection instead of a server bug and so Invalid is more appropriate than Server error here. A new protocol-agonistic MessageErrorType enum is hence introduced to support passing the error type from the common QueryTypeFilter to the protocol-specific response mapper.

[codspeed-hq]

Merging this PR will not alter performance

✅ 36 untouched benchmarks
⏩ 2 skipped benchmarks¹

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_{Comparing justinweng-instaclustr:1922-cassandrasinkcluster-querytypefilter-compatibility (6386101) with main (836af57)}

Footnotes

1. 2 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩

[Copilot]

Pull request overview

This PR fixes an incompatibility between QueryTypeFilter (which replaces filtered requests with Frame::Dummy) and CassandraSinkCluster (which previously assumed all requests had a Cassandra stream_id). It also introduces protocol-agnostic error classification so filtered Cassandra responses map to ErrorType::Invalid (avoiding defunct connections in the Datastax C++ driver), and adds an integration test reproducing the original failure.

Changes:

• Add MessageErrorType and thread it through error-response construction so transforms can classify errors as Internal vs Rejected (Cassandra maps to Server vs Invalid).
• Update CassandraSinkCluster / connection tracking to tolerate dummy messages instead of panicking on missing stream_id.
• Add a Cassandra cluster integration test and config that places QueryTypeFilter in front of CassandraSinkCluster.

Reviewed changes

Copilot reviewed 11 out of 11 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
shotover/src/transforms/tee.rs	Updates Tee’s mismatch error construction to pass MessageErrorType.
shotover/src/transforms/null.rs	Updates NullSink error construction to pass MessageErrorType.
shotover/src/transforms/filter.rs	Updates QueryTypeFilter to classify filtered requests as Rejected.
shotover/src/transforms/cassandra/sink_cluster/rewrite.rs	Updates internal Cassandra rewrite error construction to pass MessageErrorType.
shotover/src/transforms/cassandra/sink_cluster/mod.rs	Avoids version detection using dummy frames; generates dummy responses for dummy requests during routing.
shotover/src/transforms/cassandra/sink_cluster/connection.rs	Stops unwrapping stream_id for requests; skips missing stream_ids.
shotover/src/source_task.rs	Updates internal “bug” error responses to use MessageErrorType::Internal.
shotover/src/message/mod.rs	Introduces MessageErrorType and adds it to to_error_response / from_*_to_error_response APIs with protocol mappings.
shotover/src/frame/cassandra.rs	Allows Cassandra error responses to specify ErrorType instead of hardcoding Server.
shotover-proxy/tests/test-configs/cassandra/cluster-v4/topology-query-type-filter.yaml	New test config chaining QueryTypeFilter -> CassandraSinkCluster.
shotover-proxy/tests/cassandra_int_tests/mod.rs	New integration test validating filtered writes return ErrorType::Invalid and subsequent queries still succeed.

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[yallen-ic]

LGTM