Examples

Mammoth ships examples that validate different parts of the system.

examples/postgres_webhook

Purpose:

sample CDC-shaped event
    ↓
Mammoth delivery path
    ↓
webhook receiver

Use this when you want a deterministic happy-path delivery demo without running logical replication.

examples/live_postgres_webhook

Purpose:

PostgreSQL INSERT
    ↓
logical replication
    ↓
Mammoth
    ↓
webhook receiver

Use this when you want to validate the real PostgreSQL ingestion path.

This example exercises:

• PostgreSQL logical replication
• pgoutput-client transport
• replication slot usage
• publication subscription
• webhook delivery
• idle replication behavior

examples/transaction_webhook

Purpose:

PostgreSQL transaction
    ↓
logical replication
    ↓
TransactionEnvelope
    ↓
CDC::Concurrent::ProcessorPool
    ↓
webhook receiver

Use this when you want to validate Mammoth 0.2 transaction-level delivery.

This example exercises:

• PostgreSQL logical replication
• transaction envelope preservation
• delivery.unit: transaction
• runtime.adapter: concurrent
• webhook transaction payloads
• transaction-level checkpoint boundary foundations

Run it with:

cd examples/transaction_webhook
docker compose up --build

The receiver should log a transaction.committed payload with multiple row-level events in the events array.

examples/operational_state

Purpose:

Mammoth bootstrap
    ↓
SQLite operational database
    ↓
checkpoints + dead_letters schema

Use this when you want to inspect Mammoth's local operational memory without running PostgreSQL or a webhook receiver.

Useful commands:

bundle exec ./exe/mammoth bootstrap examples/operational_state/config/mammoth.yml
bundle exec ./exe/mammoth status examples/operational_state/config/mammoth.yml
sqlite3 examples/operational_state/.sqlite3/mammoth.db ".tables"

examples/failing_webhook_retry

Purpose:

sample CDC-shaped event
    ↓
Mammoth delivery worker
    ↓
webhook returns 500
    ↓
retry exhaustion
    ↓
SQLite dead letter

Use this to validate retry and dead-letter behavior.

After running the example, inspect the SQLite database in the Docker volume.

Expected dead-letter shape:

demo-order-1|failing_webhook|insert|public|orders|2|pending|Mammoth::DeliveryError|webhook failing_webhook returned HTTP 500

If the same persistent volume is reused across multiple runs, repeated executions may append additional dead-letter records for the same sample event.

Clear the volume for a clean run:

docker compose down -v

examples/kubernetes_helm

Purpose:

Helm chart
    ↓
Kubernetes Deployment
    ↓
PVC-backed SQLite operational state

Use this to validate chart rendering, installation, and persistence wiring.

The example expects you to provide real deployment dependencies such as PostgreSQL, secrets, publications, and webhook destinations.