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

config/config.go

@@ -19,6 +19,11 @@ type Config struct {
 	MaxConcurrentRequests int64 `yaml:"max_concurrent_requests" default:"200"`
 	MaxRequestsPerClient  int64 `yaml:"max_requests_per_client" default:"5"`
 
+	// Table-tier uplink bandwidth shaping (bytes/sec). Distinct from MaxRequestsPerClient.
+	// Empty/"0" uplink and 0 max_bytes_per_client_per_sec = disabled (current unlimited behavior).
+	UplinkBandwidth         string `yaml:"uplink_bandwidth"`            // e.g. "10MB" via go-units = bytes/sec
+	MaxBytesPerClientPerSec int64  `yaml:"max_bytes_per_client_per_sec"` // absolute per-client cap; 0 = none
+
 	// Hardening limits (security/correctness)
 	MaxObjectSize  string   `yaml:"max_object_size" default:"0"` // 0=unlimited; e.g. "256MB" protects against OOM from huge/malicious upstream responses
 	TrustedProxies []string `yaml:"trusted_proxies"`             // CIDR list; empty=never trust X-Forwarded-For (safe default). See README security notes.
@@ -186,6 +191,14 @@ func (c Config) Validate() error {
 	if c.MaxRequestsPerClient < 0 {
 		return fmt.Errorf("negative per-client limit not allowed")
 	}
+	if c.MaxBytesPerClientPerSec < 0 {
+		return fmt.Errorf("negative max_bytes_per_client_per_sec not allowed")
+	}
+	if c.UplinkBandwidth != "" && c.UplinkBandwidth != "0" {
+		if _, err := units.FromHumanSize(c.UplinkBandwidth); err != nil {
+			return fmt.Errorf("invalid uplink_bandwidth: %w", err)
+		}
+	}
 
 	if c.Cache.Memory.GCAlgorithm != "" {
 		switch c.Cache.Memory.GCAlgorithm {