feat: add low-noise Redis observability

[upman]

Summary

Adds low-noise visibility into application Redis latency without enabling per-command OpenTelemetry spans.

• records logical Redis operation count and latency in Prometheus, grouped by bounded client, use case, operation, and status labels
• aggregates Redis calls, duration, errors, maximum call time, and the ten most expensive use cases onto the existing HTTP request span
• covers Keyv caches, sessions, rate limits, concurrency, principals, stream jobs and pub/sub, MCP registry scans, and leader election
• excludes connection lifecycle pings and global Redis maintenance commands; namespace-scoped cache clears are recorded as one logical operation

Change Type

• New feature (non-breaking change which adds functionality)

Testing

• npx tsc --noEmit -p packages/api/tsconfig.json
• ESLint on all changed files
• focused API suites: 75 tests passed
• broad API unit suite: 7,022 tests passed
• npm run build --workspace=@librechat/api

Test Configuration:

• Node.js 22.21.0

Checklist

• My code adheres to this project style guidelines
• I have performed a self-review of my own code
• My changes do not introduce new warnings
• I have written tests demonstrating that this feature works
• Local unit tests pass with my changes

[Copilot]

Pull request overview

Adds low-noise Redis observability to the API by aggregating logical Redis activity into Prometheus metrics and attaching per-request Redis summaries to the existing OpenTelemetry HTTP span, without enabling per-command OTel spans.

Changes:

• Introduces redisTelemetry helpers to observe logical Redis operations and aggregate them onto the request span via AsyncLocalStorage.
• Instruments Keyv caches and selected ioredis clients/usages (streams, concurrency, leader election, MCP registry scans, rate limiting) to emit bounded-label Prometheus metrics.
• Extends the Prometheus metrics module with Redis operation counters + latency histogram, plus unit tests validating the new metrics output.

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
packages/api/src/telemetry/middleware.ts	Starts/stops per-request Redis aggregation and runs downstream middleware within Redis telemetry context.
packages/api/src/telemetry/middleware.spec.ts	Adds coverage ensuring Redis aggregation is attached to the stored request span.
packages/api/src/stream/implementations/RedisJobStore.ts	Wraps the stream ioredis client with Redis instrumentation for generation stream use case.
packages/api/src/stream/implementations/RedisEventTransport.ts	Instruments publisher/subscriber ioredis clients for pub/sub stream transport use case.
packages/api/src/middleware/concurrency.ts	Instruments the ioredis client used by concurrency Lua scripts.
packages/api/src/mcp/registry/cache/ServerConfigsCacheRedis.ts	Wraps Redis SCAN iteration in a logical “scan” observation for MCP registry cache reads.
packages/api/src/cluster/LeaderElection.ts	Observes Redis get/set/eval operations used for leader election.
packages/api/src/cache/redisTelemetry.ts	New core module implementing request aggregation, bounded label normalization, and ioredis/Keyv instrumentation.
packages/api/src/cache/redisTelemetry.spec.ts	New unit tests covering use case normalization, aggregation behavior, nested call de-duping, and pipeline error detection.
packages/api/src/cache/principals.ts	Instruments Redis client used by the user principals cache path.
packages/api/src/cache/index.ts	Re-exports redis telemetry utilities from the cache module barrel.
packages/api/src/cache/cacheFactory.ts	Instruments standard Keyv caches, session store Redis client, and rate-limit sendCommand calls.
packages/api/src/app/metrics.ts	Adds Redis operation counter + duration histogram and exposes recordRedisOperation.
packages/api/src/app/metrics.spec.ts	Adds tests verifying Redis metrics are emitted and labeled correctly.

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[upman]

@codex review

[chatgpt-codex-connector]

Codex Review: Didn't find any major issues. What shall we delve into next?

Reviewed commit: ba109bda2e

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