Spice Kafka Starter

Unified documentation: spiceframework.dev/integrations/kafka.

starter-kafka provides a synchronous idempotent Kafka producer and a bounded, sequential consumer group for Spice applications. Both are ordinary Go values with explicit construction and cleanup; there is no global client, reflection, environment discovery, or network I/O during construction.

Install

go get github.com/spice-framework/starter-kafka@latest

Go 1.26.5 is required. Supported Spice core boundaries are declared in spice-compatibility.json.

Producer

publisher, cleanup, err := kafka.Open(kafka.Config{
    Brokers:       []string{"broker.example:9093"},
    ClientID:      "orders",
    Username:      config.Username,
    Password:      config.Password,
    SASLMechanism: kafka.SASLSCRAMSHA256,
    TLSConfig: &tls.Config{
        MinVersion: tls.VersionTLS12,
        RootCAs:    roots,
        ServerName: "broker.example",
    },
})

The producer is idempotent, requires all in-sync replica acknowledgements, bounds batch size and timeouts, and publishes synchronously. Close flushes with the caller's lifecycle context and is idempotent.

Consumer group

consumer, cleanup, err := kafka.OpenConsumer(kafka.ConsumerConfig{
    Transport: producerConfig,
    GroupID:   "inventory",
    Topics:    []string{"orders.placed"},
})

Run handles records sequentially. Successful deliveries and explicit rejections commit; retryable handler failures remain uncommitted and return to the caller for an explicit restart/backoff policy. Auto-commit is disabled and poll size is bounded.

Security

• TLS 1.2 or newer with certificate verification is the default.
• Authentication is independently required by default.
• PLAIN, SCRAM-SHA-256, and SCRAM-SHA-512 are explicit choices. PLAIN should only be used with verified TLS.
• Plaintext and unauthenticated operation require separate, explicit local development flags.
• Broker addresses, identities, credentials, timeouts, topics, headers, and payload boundaries are validated.
• Producer and consumer observations contain only topic/group/partition, duration, and outcome information—never message keys, headers, or payloads.

Applications own secret loading, CA roots, retry/backoff policy, and franz-go hooks used for tracing or metrics.

Broker acceptance

The repository acceptance suite runs producer authentication failure, connectivity, ordered publication, consumer-group delivery, manual commits, restart/no-redelivery, cancellation, and cleanup against Redpanda v25.1.9 at the immutable multi-platform image digest documented in docs/broker-acceptance.md.

That evidence validates the Kafka protocol path against Redpanda. Production teams must additionally run the same suite against their broker distribution, version, TLS certificates, authentication mechanism, replication policy, and failure topology before approving deployment.

Verification

make check
make compatibility
make lint
make release-rehearsal
make security
make verify
make verify-release

Release rehearsal runs the exact spice-dev tool authorized by go.mod twice from one inert plan, entirely from vendor with network and workspace resolution disabled. It requires byte-identical outputs, canonical checksums, central-renderer SPDX provenance, and no rehearsal signatures on Windows and Linux.

See docs/dependency-review.md and docs/support.md.

Releases

The repository builds deterministic source-only releases with an SPDX 2.3 SBOM, SHA-256 checksums, and Ed25519 signatures. See the exact artifact and clean-tag ceremony in docs/releasing.md. The protected central workflow is the sole release authority. It validates the candidate without credentials, renders and signs with immutable trusted code, authenticates the result with an independent verifier, and publishes only after separate protected approvals.

License

Apache License 2.0.