[feat][io] Add Debezium MariaDB source connector

[david-streamlio]

Fixes #65

Motivation

Debezium ships a MariaDB source connector (io.debezium:debezium-connector-mariadb, present in the debezium-bom at our pinned version), but this repository did not wrap it. We wrapped 5 of Debezium's 12 source connectors; MariaDB was the most valuable gap:

• Debezium split the MariaDB connector out of the MySQL connector, and both now build on the shared debezium-connector-binlog base — so the existing debezium/mysql module is a near drop-in template.
• We already ship a MariaDB JDBC sink (integration test added in [improve][test] Add MariaDB JDBC sink integration test #59), so this completes the story for that database.

Modifications

New debezium/mariadb module (pulsar-io-debezium-mariadb), mirroring debezium/mysql:

• DebeziumMariaDbSource extending DebeziumSource, pinning Debezium's MariaDbConnector / MariaDbConnectorTask
• Service descriptor (META-INF/services/pulsar-io.yaml) and sample source config
• Version catalog entry, settings.gradle.kts include, and wiring into distribution/io, docker/pulsar-all, the assembly XML, and docs

Test suite

Unit tests (DebeziumMariaDbSourceConfigTest, 7 cases, no database required) cover the connector/task class contract, which is otherwise a silent misconfiguration that only surfaces at runtime:

• both keys are defaulted when absent, and accepted when explicitly set to the matching value
• a mismatched connector or task class is rejected — specifically guarding against pointing the MariaDB source at the MySQL connector, an easy mistake now that the two share a binlog base
• both class names resolve via Class.forName, proving the string literals name real classes on the runtime classpath

Integration test (DebeziumMariaDbSourceTest) runs the source against a real mariadb:11.4 server plus a PulsarContainer for Debezium's schema history, seeds two rows, and asserts the initial snapshot emits CDC records.

Verifying this change

DebeziumMariaDbSourceConfigTest > 7 tests PASSED
DebeziumMariaDbSourceTest > testMariaDbCdcEvents PASSED
BUILD SUCCESSFUL in 24s

NAR packaging verified: pulsar-io-debezium-mariadb-4.3.0-SNAPSHOT.nar builds.

Notes

• Uses the GenericContainer pattern rather than Testcontainers' MariaDBContainer: debezium-bom pins Testcontainers core to 2.x, while the specialized modules still target 1.21.x and reference shaded classes removed in 2.x (see [improve][test] Add Debezium Oracle source integration test #62).
• The integration test carries a timeOut because source.read() blocks — without it, a connector that never emits would hang until the CI job's own timeout rather than failing.
• The MariaDB 3.x JDBC driver (which arrives transitively with the connector, so the NAR has it) only registers the jdbc:mariadb: scheme and no longer handles jdbc:mysql: URLs.
• MariaDB is single-partition, so it does not hit the task.id gap described in [Bug] Debezium SQL Server source fails to start: multi-partition connector never receives task.id #61.

[Copilot]

Pull request overview

Adds a new Debezium-based MariaDB source connector module to the Pulsar connectors repository, mirroring the existing Debezium MySQL module and wiring it into build/distribution artifacts.

Changes:

• Introduces debezium/mariadb (pulsar-io-debezium-mariadb) with DebeziumMariaDbSource, service descriptor, and sample config.
• Adds unit tests validating connector/task class defaulting and mismatch rejection, plus an end-to-end Testcontainers integration test against mariadb:11.4.
• Wires the new NAR into Gradle settings, version catalog, docs, docker image build, and distribution assembly.

Reviewed changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated no comments.

Show a summary per file

File	Description
settings.gradle.kts	Includes the new debezium:pulsar-io-debezium-mariadb subproject.
gradle/libs.versions.toml	Adds the Debezium MariaDB connector artifact to the version catalog.
docs/build.gradle.kts	Ensures docs aggregation includes the new Debezium MariaDB module.
docker/pulsar-all/build.gradle.kts	Includes the MariaDB Debezium NAR in the “pulsar-all” connector set.
distribution/io/src/assemble/io.xml	Adds the MariaDB Debezium NAR to the IO distribution assembly list.
distribution/io/build.gradle.kts	Includes the MariaDB Debezium NAR in the IO distribution dependencies.
debezium/mariadb/build.gradle.kts	Defines the new module’s build, dependencies, and test dependencies.
debezium/mariadb/src/main/java/org/apache/pulsar/io/debezium/mariadb/DebeziumMariaDbSource.java	Implements the MariaDB Debezium Source wrapper by pinning connector/task classes.
debezium/mariadb/src/main/java/org/apache/pulsar/io/debezium/mariadb/package-info.java	Adds package metadata for the new module.
debezium/mariadb/src/main/resources/META-INF/services/pulsar-io.yaml	Registers the connector for discovery via Pulsar IO service loading.
debezium/mariadb/src/main/resources/debezium-mariadb-source-config.yaml	Provides a sample YAML config for running the MariaDB source.
debezium/mariadb/src/test/java/org/apache/pulsar/io/debezium/mariadb/DebeziumMariaDbSourceConfigTest.java	Unit tests validating connector/task class defaulting and validation.
debezium/mariadb/src/test/java/org/apache/pulsar/io/debezium/mariadb/DebeziumMariaDbSourceTest.java	Integration test exercising snapshot CDC against a real MariaDB container + Pulsar schema history.

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