cache: Per-client fair-share bandwidth on table uplink

steamcache/handler.go

@@ -38,10 +38,14 @@ type Options struct {
 	// NegativeTTL is a Go duration string for 404/410 negative cache entries.
 	// Empty defaults to 5m. "0" / "0s" disables storing negatives.
 	NegativeTTL string
+
+	// Table-tier uplink bandwidth shaping (bytes/sec). Empty/0 = disabled.
+	UplinkBandwidth         string
+	MaxBytesPerClientPerSec int64
 }
 
 func NewWithOptions(o Options) (*SteamCache, error) {
-	return New(o.Address, o.MemorySize, o.DiskSize, o.DiskPath, o.Upstream, o.MemoryGC, o.DiskGC, o.MaxConcurrentRequests, o.MaxRequestsPerClient, o.MaxObjectSize, o.TrustedProxies, o.NegativeTTL)
+	return New(o.Address, o.MemorySize, o.DiskSize, o.DiskPath, o.Upstream, o.MemoryGC, o.DiskGC, o.MaxConcurrentRequests, o.MaxRequestsPerClient, o.MaxObjectSize, o.TrustedProxies, o.NegativeTTL, o.UplinkBandwidth, o.MaxBytesPerClientPerSec)
 }
 
 // handleSpecialEndpoints handles non-content paths (health, heartbeat, metrics) and
@@ -413,6 +417,15 @@ func (sc *SteamCache) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	// Per-client uplink bandwidth shaping (table-tier). Distinct from concurrency limits above.
+	if sc.bandwidth != nil && sc.bandwidth.enabled() {
+		lim, release := sc.bandwidth.acquire(clientIP)
+		defer release()
+		if lim != nil {
+			w = &limitedResponseWriter{ResponseWriter: w, lim: lim, ctx: r.Context()}
+		}
+	}
+
 	// Check if this is a request from a supported service
 	if service, isSupported := sc.detectService(r); isSupported {
 		// Cache key is the path only, never the Host: Steam rotates CDN hostnames