Merge pull request #3700 from ethereum-optimism/feat/proxyd-allow-backend-lim-disable

proxyd: Allow disabling backend rate limiting

.changeset/flat-windows-trade.md

+---
+'@eth-optimism/proxyd': minor
+---
+
+Allow disabling backend rate limiter

proxyd/backend_rate_limiter.go

@@ -5,6 +5,7 @@ import (
 	"crypto/rand"
 	"encoding/hex"
 	"fmt"
+	"math"
 	"sync"
 	"time"
 
@@ -256,5 +257,30 @@ func randStr(l int) string {
 	return hex.EncodeToString(b)
 }
 
-type ServerRateLimiter struct {
+type NoopBackendRateLimiter struct{}
+
+var noopBackendRateLimiter = &NoopBackendRateLimiter{}
+
+func (n *NoopBackendRateLimiter) IsBackendOnline(name string) (bool, error) {
+	return true, nil
+}
+
+func (n *NoopBackendRateLimiter) SetBackendOffline(name string, duration time.Duration) error {
+	return nil
+}
+
+func (n *NoopBackendRateLimiter) IncBackendRPS(name string) (int, error) {
+	return math.MaxInt, nil
+}
+
+func (n *NoopBackendRateLimiter) IncBackendWSConns(name string, max int) (bool, error) {
+	return true, nil
+}
+
+func (n *NoopBackendRateLimiter) DecBackendWSConns(name string) error {
+	return nil
+}
+
+func (n *NoopBackendRateLimiter) FlushBackendWSConns(names []string) error {
+	return nil
 }

proxyd/config.go

@@ -42,13 +42,14 @@ type MetricsConfig struct {
 }
 
 type RateLimitConfig struct {
-	UseRedis         bool                                `toml:"use_redis"`
-	BaseRate         int                                 `toml:"base_rate"`
-	BaseInterval     TOMLDuration                        `toml:"base_interval"`
-	ExemptOrigins    []string                            `toml:"exempt_origins"`
-	ExemptUserAgents []string                            `toml:"exempt_user_agents"`
-	ErrorMessage     string                              `toml:"error_message"`
-	MethodOverrides  map[string]*RateLimitMethodOverride `toml:"method_overrides"`
+	UseRedis                 bool                                `toml:"use_redis"`
+	EnableBackendRateLimiter bool                                `toml:"enable_backend_rate_limiter"`
+	BaseRate                 int                                 `toml:"base_rate"`
+	BaseInterval             TOMLDuration                        `toml:"base_interval"`
+	ExemptOrigins            []string                            `toml:"exempt_origins"`
+	ExemptUserAgents         []string                            `toml:"exempt_user_agents"`
+	ErrorMessage             string                              `toml:"error_message"`
+	MethodOverrides          map[string]*RateLimitMethodOverride `toml:"method_overrides"`
 }
 
 type RateLimitMethodOverride struct {

proxyd/integration_tests/testdata/backend_rate_limit.toml

@@ -15,4 +15,7 @@ max_rps = 2
 backends = ["good"]
 
 [rpc_method_mappings]
-eth_chainId = "main"
\ No newline at end of file
+eth_chainId = "main"
+
+[rate_limit]
+enable_backend_rate_limiter = true
\ No newline at end of file

proxyd/integration_tests/testdata/out_of_service_interval.toml

@@ -19,4 +19,7 @@ ws_url = "$BAD_BACKEND_RPC_URL"
 backends = ["bad", "good"]
 
 [rpc_method_mappings]
-eth_chainId = "main"
\ No newline at end of file
+eth_chainId = "main"
+
+[rate_limit]
+enable_backend_rate_limiter = true
\ No newline at end of file

proxyd/integration_tests/testdata/ws.toml

@@ -26,3 +26,6 @@ backends = ["good"]
 
 [rpc_method_mappings]
 eth_chainId = "main"
+
+[rate_limit]
+enable_backend_rate_limiter = true
\ No newline at end of file

proxyd/proxyd.go

@@ -53,11 +53,15 @@ func Start(config *Config) (func(), error) {
 
 	var lim BackendRateLimiter
 	var err error
-	if redisClient == nil {
-		log.Warn("redis is not configured, using local rate limiter")
-		lim = NewLocalBackendRateLimiter()
+	if config.RateLimit.EnableBackendRateLimiter {
+		if redisClient != nil {
+			lim = NewRedisRateLimiter(redisClient)
+		} else {
+			log.Warn("redis is not configured, using local rate limiter")
+			lim = NewLocalBackendRateLimiter()
+		}
 	} else {
-		lim = NewRedisRateLimiter(redisClient)
+		lim = noopBackendRateLimiter
 	}
 
 	// While modifying shared globals is a bad practice, the alternative