Feature/redis infrastructure

[tsekovTriesCoding]

What's New

1. Session Caching (auth-service)

• Cache /auth/me responses in Redis for 15 minutes via UserSessionCacheService
• Evicted on logout, account suspension, or status change
• Eliminates a DB query + REST call to user-service on every page navigation

2. Token Blocklist (auth-service)

• TokenBlocklistService blocks revoked access tokens in Redis with TTL matching token remaining lifetime
• Checked in AuthController.getCurrentUser() before serving /auth/me
• Fail-open on Redis unavailability (graceful degradation)

3. Rate Limiting (api-gateway)

• RateLimitFilter uses a Redis Lua script for atomic sliding-window rate limiting
• Tiered limits: auth endpoints (20/min), admin (200/min), default (100/min)
• Configurable via RateLimitProperties in application.yaml
• Fail-open: if Redis is down, requests pass through

4. Idempotency Deduplication (finpay-outbox-starter)

• RedisIdempotentConsumerService accelerates duplicate event detection using Redis before DB lookup
• Write-through pattern: DB first, then Redis cache
• Auto-configured via @ConditionalOnBean(StringRedisTemplate); falls back to DB-only without Redis
• Backfills Redis on DB hit for self-healing cache

5. Wallet & Analytics Caching (wallet-service)

• WalletCacheService: caches wallet reads for 10 seconds, evicted on any wallet mutation (deposit, withdraw, transfer, freeze, unfreeze)
• WalletAnalyticsCacheService: caches admin dashboard metrics for 30 seconds

6. Secure Refresh Token Storage (auth-service)

• Breaking change: removed raw token column from refresh_tokens table
• Only the SHA-256 hash (tokenHash, 64-char hex) is persisted - raw token is never stored
• Lookups via findByTokenHash() after hashing the incoming token
• Extracted sha256() to TokenHashUtil utility class (clean entity, no crypto in JPA model)
• Follows the same pattern used by GitHub, Stripe, and Laravel Sanctum

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Resilience

• All Redis operations wrapped in try-catch with graceful degradation
• Every cache/blocklist service logs warnings on Redis failure and continues without crashing
• Rate limiter fails open - no Redis means no rate limiting, not a 500

Infrastructure

• Redis 7 Alpine added to docker-compose.yml (256MB, allkeys-lru eviction)
• spring-boot-starter-data-redis added to parent POM
• StringRedisTemplate used everywhere (auto-configured by Spring Boot, no custom RedisConfig)

Testing

• Redis Testcontainers (redis:7-alpine) added to all 5 service TestcontainersConfig files
• New unit tests: TokenBlocklistServiceTest, UserSessionCacheServiceTest, RateLimitFilterTest, RedisIdempotentConsumerServiceTest
• All existing tests updated for tokenHash changes
• All 8 services pass: 118 (auth) + all others green

Commits:

• 704b600 feat: add Redis infrastructure for caching, rate limiting, and idempotency
• 84282df refactor: store only SHA-256 hash of refresh tokens