feat: event-driven tenant discovery in MultiTenantConsumer

[jeffersonrodrigues92]

Summary

• Replace polling-based tenant discovery with Redis Pub/Sub + lazy-load
• Consumer pods boot with empty tenant map, subscribe to tenant-events:*, lazy-load on first request
• All state changes arrive via Redis Pub/Sub events — polling eliminated entirely
• 12 event types handled (tenant lifecycle + service association + credentials + connections)

Changes

New package: commons/tenant-manager/event/

• TenantLifecycleEvent envelope, 12 event type constants, 7 typed payload structs
• TenantEventListener — Redis Pub/Sub subscriber with graceful shutdown
• ParseEvent(), ChannelForTenant() helpers
• Payloads aligned with publisher contract (tenant-manager feat(circuitbreaker): implement circuit breaker package with health checks and state management #222)

New components in consumer/

• TTL cache (multi_tenant_cache.go) — 12h default, lazy eviction, thread-safe
• Lazy-load (multi_tenant_lazy.go) — on-demand tenant fetch with per-tenant mutex
• Event dispatch (multi_tenant_events.go + _handlers.go) — 12 handlers with service filtering, jitter, full TenantConfig population

Breaking changes

• NewMultiTenantConsumerWithError() now requires redisClient parameter
• WithRedisClient() option removed (now constructor param)
• Deleted all polling code: syncActiveTenants(), discoverTenants(), etc.
• Deleted multi_tenant_sync.go, multi_tenant_revalidate.go

Fixes (from review feedback)

• Aligned JSON payload structs with publisher contract (modules as []string, secret_paths as nested map, messaging_config with flat rabbitmq_secret_path)
• handleServiceAssociated / handleServiceReactivated now populate full TenantConfig (ConnectionSettings, Databases, Messaging)
• Close() stops event listener outside c.mu lock to prevent deadlock

Test plan

• All 15 tenant-manager packages pass with -race
• ~60+ new test cases covering event types, listener, cache, lazy-load, dispatch, Run/Close
• Lint: 0 issues
• No panic() in production code
• Integration test with real Redis Pub/Sub (future PR)

Closes #396

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Caution

Review failed

The pull request is closed.

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📥 Commits

Reviewing files that changed from the base of the PR and between 7f9fac0 and 14cd0e6.

📒 Files selected for processing (1)

• commons/tenant-manager/consumer/multi_tenant.go

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Walkthrough

The MultiTenantConsumer.Close() method's synchronization pattern has been refactored to reduce lock contention. Previously, the entire method held the c.mu mutex via defer unlock. Now, the mutex is acquired and released in two separate blocks: first to atomically set c.closed=true and snapshot c.eventListener, then released before calling listener.Stop(). After the listener stops, the mutex is re-acquired with defer unlock to perform tenant-context cancellation, clear internal maps (c.tenants, c.knownTenants), and optionally close pmClient. This change eliminates holding the lock during the potentially blocking listener.Stop() call while maintaining correctness for subsequent cleanup operations.

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