CassandraContainer

A single-node Apache Cassandra container.

Default image: floats to cassandra:latest — this module previously pinned cassandra:5.0.8. Guest port: 9042 (CQL native protocol) Expected repository: cassandra

Compatibility checking

with_image takes impl Into<ImageName> and keeps the image verbatim. start() then checks that image’s repository (registry host, tag, and digest stripped) against cassandra before any backend is resolved or any sandbox is created, which keeps the constructors infallible like every other module’s. A mismatch returns RightsizeError::IncompatibleImage; ImageName::parse(image) .as_compatible_substitute_for("cassandra") is the escape hatch for a verified drop-in replacement from another registry. new() goes through this same check against its own floating reference, so it can never fail in practice.

GPG_KEYS must be overridden to a tab-free value — this is not optional

cassandra:5.0.8’s baked env includes a GPG_KEYS value containing a literal TAB character (a package-signing key list built with tab-separated continuation, same shape as the DOCKER_PG_LLVM_DEPS/postgres:*-alpine case documented on PostgresContainer). msb 0.6.6’s krun VMM builder panics on any baked env value containing a control character, and it panics before the guest ever boots — reproduced directly, identical msb run invocation:

sandbox process exited (signal: 6 (SIGABRT)) before agent relay became available

with msb logs --source system showing the actual panic site:

panicked at msb_krun_vmm-0.1.25/src/builder.rs:1154: ... Err value: InvalidAscii

.with_env("GPG_KEYS", "") sidesteps it: GPG_KEYS is build-time-only in this image (used only when the image itself is built, to import signing keys), so overriding it has zero effect at container-run time. Verified directly: the identical msb run aborts with the panic above without this override and boots clean with it. Docker is unaffected either way — this override is a no-op there, not a workaround for a docker-specific problem. This module always sets it; it is not exposed as a builder override, because there is no reason a caller would ever want the tab-bearing value back.

Heap — kept small on purpose

MAX_HEAP_SIZE=512M and HEAP_NEWSIZE=128M keep the JVM’s own heap modest rather than letting it size itself off host memory, the same reasoning this crate’s other JVM modules apply via with_memory_limit alone — here the image’s own env knobs are the more direct lever.

Memory limit — 2560 MB, verified at that value

with_memory_limit(2560) is this module’s default, verified against a real boot with the heap settings above.

Readiness — Starting listening for CQL clients, observed at 58s

That line is Cassandra’s own log signal that the CQL native protocol port (9042) is accepting connections. Startup timeout is 300s: 58s was observed on a quiet local machine, and this crate’s precedent for a single heavyweight JVM server — 180s for KeycloakContainer and MySqlContainer’s loaded-CI-runner case — undershoots a server this much heavier than either, so the budget here is wider rather than reused as-is.

Verified end to end: cqlsh ran CREATE KEYSPACE → CREATE TABLE → INSERT → SELECT, and the row came back.

Complete example

use rightsize_modules::CassandraContainer;

#[tokio::test]
async fn keyspace_round_trips_via_cqlsh() -> Result<(), Box<dyn std::error::Error>> {
    let guard = CassandraContainer::new().start().await?;

    let cql = "CREATE KEYSPACE IF NOT EXISTS smoke WITH REPLICATION = \
               {'class': 'SimpleStrategy', 'replication_factor': 1}; \
               CREATE TABLE IF NOT EXISTS smoke.t (id int PRIMARY KEY, val text); \
               INSERT INTO smoke.t (id, val) VALUES (1, 'rightsize');";
    guard.exec(&["cqlsh", "-e", cql]).await?;

    let select = guard
        .exec(&["cqlsh", "-e", "SELECT val FROM smoke.t WHERE id = 1;"])
        .await?;
    assert!(select.stdout.contains("rightsize"));

    guard.stop().await?;
    Ok(())
}

(The round-trip goes through the image’s own bundled cqlsh binary via exec rather than a Cassandra driver crate — see crates/rightsize-modules/tests/cassandra_it.rs.)

Backend notes

with_memory_limit(2560) and the GPG_KEYS override are both set unconditionally by the module — see Memory and the GPG_KEYS section above. The GPG_KEYS override is required to boot at all on microsandbox; it is a harmless no-op on Docker.