apache
feature(core): add core connection-pool monitoring (implementation, cache)
- [x] I have read the CONTRIBUTING.md guidelines.
- [x] I have registered the PR changes.
Ⅰ. Describe what this PR did
Add the core connection-pool monitoring implementation (transport-agnostic) for CPM backend.
Domain / Model
ConnectionPoolInfo: runtime snapshot DTO for pool metrics.
Providers
DruidConnectionPoolMetrics: collect metrics from Druid.HikariConnectionPoolMetrics: collect metrics from HikariCP.
Collector
DataSourceConnectionPoolCollector: aggregate metrics from multiple providers.
Service
ConnectionPoolMonitor: periodic collection and read APIs.
Cache
ConnectionPoolInfoCache: in-memory storage for fast reads.
Integration Hook
DataSourceProxyEnhancer: lifecycle hook for automatic registration/unregistration of monitored DataSources.
This PR does not include any private protocol / networking code (Netty / gRPC).
Transport (Netty / gRPC / REST) will be integrated in a follow-up PR to keep layering clean.
Ⅱ. Does this pull request fix one issue?
No. It introduces the core capability for the connection-pool-monitor backend, independent of transport.
Ⅲ. Why don't you add test cases (unit test/integration test)?
Basic unit tests will be added with the follow-up PR.
Ⅳ. Describe how to verify it
This PR introduces transport-agnostic core logic only. Verification will be provided by
follow-up unit tests that cover providers (Druid / Hikari), the collector, the monitor, and the cache.
Those tests will be sufficient to validate the functionality end-to-end without requiring a running console.
Ⅴ. Special notes for reviews
- All new Java files include ASF headers.
- No Netty / gRPC classes are included in this PR; those will live in a separate PR.
- The design keeps providers → collector → monitor → cache → enhancer independent from transport for easy pluggability.
- Package structure may be further refined after backend transport abstraction (e.g., gRPC integration) is finalized.
