Files
homelab-frontend/internal/server/router.go
T
rockandAdmin Bot ef5e736673
CI / CI (push) Successful in 3m20s
feat(cag): CAG integration — memory adapter, warmup semaphore, cache-aware routing (#47)
## Summary

Three issues in one PR. Implements Cache-Augmented Generation (CAG) support in the api-gw.

---

### #44 — Memory ServiceAdapter: standing-context resource

- Code-registers `memory` adapter with `standing-context` resource (`POST /memory/standing-context`)
- Fixes dispatcher bug: method-level `Auth.Capability` override now respected (was always using verb-derived capability)
- Auth: `memory:read` required via method-level override; `memory:write` for ingest
- `MEMORY_UPSTREAM_URL` env configures upstream

### #45 — Continuous batching: warmup deprioritisation + per-backend semaphore

- In-memory bounded queue per backend: `VLLM_MAX_QUEUE_DEPTH` slots (default 20)
- Concurrency limiter: `VLLM_MAX_NUM_SEQS` slots (default 4)
- `X-Poimen-Warmup: true` → sleep `WARMUP_DELAY_MS` (default 500ms) before queue entry, strip header, add `X-Priority: low`
- Queue full → 503 immediately, no goroutine pile-up
- Metrics: `warmup_requests_delayed_total`, `queue_full_requests_total` at `/metrics`

### #46 — Cache-aware routing: rendezvous hash + prefix cache hit logging

- `addresses: [...]` YAML field for multi-backend models (backward-compat with `address`)
- `X-Poimen-Cache-Key` header → rendezvous-hash backend selection (same key = same GPU)
- No cache key → round-robin
- Failed backend excluded 30s; next-highest-score fallback
- `vllm-num-cached-tokens` response header captured → `vllm_prefix_cache_hit_tokens_total` counter + structured log

---

## Verification

```
go build ./...    ✅
go vet ./...      ✅
go test -race ./... ✅ (all packages, 0 races)
```

## Reviewer verdicts

- reviewer-sre: SIGN-OFF
- reviewer-quality: SIGN-OFF

## Non-blocking findings (🟡🔵 only)

- `getOrCreateTransport` not goroutine-safe by design; pre-population invariant documented
- `time.Sleep(warmupDelay)` holds goroutine; context-cancel alternative left as TODO
- OTel trace_id not propagated into CAG log events (existing gap)

Closes #44 Closes #45 Closes #46

---------

Co-authored-by: Admin Bot <[email protected]>
Reviewed-on: #47
2026-09-27 11:16:40 +00:00

92 lines
2.9 KiB
Go

package server
import (
"net/http"
"forgejo.riotpiao.com/rock/homelab-frontend/internal/serviceadapter"
"forgejo.riotpiao.com/rock/homelab-frontend/internal/webhook"
)
// Router implements an HTTP handler that routes health endpoints,
// ServiceAdapter X-Service requests, Temporal workflow endpoints,
// and other requests to upstream handlers.
type Router struct {
healthChecker *HealthChecker
dispatcher *serviceadapter.Dispatcher
temporalHandler http.Handler
upstreamHandler http.Handler
forgejoWebhook *webhook.ForgejoHandler
metricsHandler http.Handler
}
// NewRouter creates a new router with health endpoints.
// Health endpoints (/healthz and /readyz) are handled locally.
// X-Service requests are dispatched via ServiceAdapter CRD.
// Temporal endpoints (/workflow*) are routed to temporalHandler.
// All other paths are passed to the upstream handler.
func NewRouter(healthChecker *HealthChecker, dispatcher *serviceadapter.Dispatcher, temporalHandler http.Handler, upstreamHandler http.Handler) *Router {
return &Router{
healthChecker: healthChecker,
dispatcher: dispatcher,
temporalHandler: temporalHandler,
upstreamHandler: upstreamHandler,
forgejoWebhook: webhook.NewForgejoHandler(),
}
}
// SetMetricsHandler registers the Prometheus /metrics endpoint handler.
func (r *Router) SetMetricsHandler(h http.Handler) {
r.metricsHandler = h
}
// ServeHTTP implements http.Handler.
// Priority order:
// 1. /healthz and /readyz to health handlers
// 2. X-Service header to ServiceAdapter dispatcher (phase 8) - PREFERRED routing method
// 3. /workflow* to temporal handler - DEPRECATED: use X-Service: workflow instead
// 4. All other paths to upstream handler (phase 0-7)
func (r *Router) ServeHTTP(w http.ResponseWriter, req *http.Request) {
// Health endpoints first
switch req.URL.Path {
case "/healthz":
LivenessHandler(r.healthChecker)(w, req)
return
case "/readyz":
ReadinessHandler(r.healthChecker)(w, req)
return
case "/metrics":
if r.metricsHandler != nil {
r.metricsHandler.ServeHTTP(w, req)
return
}
}
// X-Service (ServiceAdapter) routing - checked before path-based routing
// PREFERRED: All service routing should use X-Service header pattern for consistency,
// auth enforcement, and resource-based access control.
if req.Header.Get("X-Service") != "" {
if r.dispatcher != nil {
r.dispatcher.Dispatch(w, req)
return
}
}
// Forgejo webhook receiver — no auth, HMAC-verified by handler
if req.URL.Path == "/v1/webhooks/forgejo" {
r.forgejoWebhook.ServeHTTP(w, req)
return
}
// Workflow endpoints
// DEPRECATED: Path-based /workflow routing is legacy.
// New clients should use X-Service: workflow header instead for consistent auth.
switch req.URL.Path {
case "/workflow", "/workflow/health", "/workflow/metrics":
r.temporalHandler.ServeHTTP(w, req)
return
}
// Default: upstream handler (all other paths)
r.upstreamHandler.ServeHTTP(w, req)
}