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Capability matrix

Which Pattern × Adapter combinations ship today, and which gaps remain.

The roadmap carries the live state. This page is the at-a-glance view.

Vocabulary

  • Pattern: user-facing class. Lock, LeaderElection, TaskLock, TTLCache, RateLimiter, CircuitBreaker, Idempotency, Retry, Bulkhead, Fallback, Timeout, Shield.
  • Adapter: concrete implementation of a Backend Protocol. RedisLockAdapter, PostgresLockAdapter, MemoryCacheAdapter, SQLiteLockAdapter, KubernetesLockAdapter, and so on.
  • Backend: the Protocol class an Adapter satisfies. LockBackend, LeaderElectionBackend, CacheBackend, RateLimiterBackend, CircuitBreakerBackend.
  • Provider: vendor configuration plus native client, shared by Adapters that talk to the same service. RedisProvider, PostgresProvider, SQLiteProvider. Memory and Kubernetes Adapters do not use a Provider.

See Backends and Adapters for the full model.

Matrix

Pattern Memory Redis Postgres SQLite Kubernetes
Lock ✅ ✅ ✅ ✅ ✅
TaskLock ✅ ✅ ✅ ✅ ✅
LeaderElection ✅ ✅ ✅ N/A ✅
@tasks.cron ✅ ✅ ✅ ✅ N/A
TTLCache ✅ ✅ ✅ ✅ N/A
Idempotency ✅ ✅ ✅ ✅ N/A
RateLimiter ✅ ✅ ✅ ✅ N/A
CircuitBreaker ✅ ✅ ✅ ✅ N/A
Retry ✅ N/A N/A N/A N/A
Bulkhead ✅ N/A N/A N/A N/A
Fallback ✅ N/A N/A N/A N/A
Timeout ✅ N/A N/A N/A N/A
Shield ✅ N/A N/A N/A N/A

Legend:

  • ✅ ships today.
  • N/A does not apply. Retry, Bulkhead, Fallback, and Timeout are in-process Patterns with no remote state to share. For Schedule (cron), Kubernetes has no Adapter on purpose: run a native Kubernetes CronJob instead. For LeaderElection, SQLite has no adapter: leader election is meaningful only across multiple nodes, and SQLite does not coordinate across nodes. Schedule (cron) on SQLite does ship, because durable cron across processes on a single host is still useful.

Picking an Adapter

  • Memory for tests, single-process apps, and Retry, Fallback, Timeout, and Bulkhead (in-process Patterns).
  • Redis when you already run Redis and want the lowest-latency distributed option. RedisProvider switches to Sentinel or Cluster from the URL scheme alone (see Providers). On Cluster the cache and lock prefixes need a hash tag.
  • Valkey when you run a Valkey server. ValkeyProvider wraps the same Redis adapters via valkey-py, so coverage and behavior match Redis exactly.
  • Postgres when Postgres is your only stateful dependency and you want one fewer service to run.
  • SQLite for single-host deployments that still need durability across restarts. The SQLite circuit breaker coordinates state across processes sharing one file on a single host, not across hosts. For fleet-wide state, use Redis or Postgres.
  • Kubernetes for Lock and LeaderElection when you want the cluster API as the coordination plane and no extra infrastructure.