proxyd: Add global flag to method overrides

This allows us to set global limits on individual RPCs that ignore any origin/user agent exemption.

.changeset/orange-panthers-impress.md

+---
+'@eth-optimism/proxyd': minor
+---
+
+Add support for global method override rate limit

proxyd/config.go

@@ -55,6 +55,7 @@ type RateLimitConfig struct {
 type RateLimitMethodOverride struct {
 	Limit    int          `toml:"limit"`
 	Interval TOMLDuration `toml:"interval"`
+	Global   bool         `toml:"global"`
 }
 
 type TOMLDuration time.Duration

proxyd/go.mod

@@ -13,7 +13,6 @@ require (
 	github.com/hashicorp/golang-lru v0.5.5-0.20210104140557-80c98217689d
 	github.com/prometheus/client_golang v1.11.0
 	github.com/rs/cors v1.8.2
-	github.com/sethvargo/go-limiter v0.7.2
 	github.com/stretchr/testify v1.7.0
 	golang.org/x/sync v0.0.0-20210220032951-036812b2e83c
 )

proxyd/go.sum

@@ -451,8 +451,6 @@ github.com/russross/blackfriday/v2 v2.0.1/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQD
 github.com/segmentio/kafka-go v0.1.0/go.mod h1:X6itGqS9L4jDletMsxZ7Dz+JFWxM6JHfPOCvTvk+EJo=
 github.com/segmentio/kafka-go v0.2.0/go.mod h1:X6itGqS9L4jDletMsxZ7Dz+JFWxM6JHfPOCvTvk+EJo=
 github.com/sergi/go-diff v1.0.0/go.mod h1:0CfEIISq7TuYL3j771MWULgwwjU+GofnZX9QAmXWZgo=
-github.com/sethvargo/go-limiter v0.7.2 h1:FgC4N7RMpV5gMrUdda15FaFTkQ/L4fEqM7seXMs4oO8=
-github.com/sethvargo/go-limiter v0.7.2/go.mod h1:C0kbSFbiriE5k2FFOe18M1YZbAR2Fiwf72uGu0CXCcU=
 github.com/shirou/gopsutil v3.21.4-0.20210419000835-c7a38de76ee5+incompatible/go.mod h1:5b4v6he4MtMOwMlS0TUMTu2PcXUg8+E1lC7eC3UO/RA=
 github.com/shirou/gopsutil v3.21.11+incompatible h1:+1+c1VGhc88SSonWP6foOcLhvnKlUeu/erjjvaPEYiI=
 github.com/shirou/gopsutil v3.21.11+incompatible/go.mod h1:5b4v6he4MtMOwMlS0TUMTu2PcXUg8+E1lC7eC3UO/RA=

proxyd/integration_tests/rate_limit_test.go

@@ -139,6 +139,19 @@ func TestFrontendMaxRPSLimit(t *testing.T) {
 		require.Nil(t, res[1].Error)
 		require.Nil(t, res[2].Error)
 	})
+
+	time.Sleep(time.Second)
+
+	t.Run("global RPC override", func(t *testing.T) {
+		h := make(http.Header)
+		h.Set("User-Agent", "exempt_agent")
+		client := NewProxydClientWithHeaders("http://127.0.0.1:8545", h)
+		limitedRes, codes := spamReqs(t, client, "eth_baz", 429, 2)
+		// use 1 and 1 here since the limit for eth_baz is 1
+		require.Equal(t, 1, codes[429])
+		require.Equal(t, 1, codes[200])
+		RequireEqualJSON(t, []byte(frontendOverLimitResponseWithID), limitedRes)
+	})
 }
 
 func spamReqs(t *testing.T, client *ProxydHTTPClient, method string, limCode int, n int) ([]byte, map[int]int) {

proxyd/integration_tests/testdata/frontend_rate_limit.toml

@@ -16,6 +16,7 @@ backends = ["good"]
 [rpc_method_mappings]
 eth_chainId = "main"
 eth_foobar = "main"
+eth_baz = "main"
 
 [rate_limit]
 base_rate = 2
@@ -27,3 +28,8 @@ error_message = "over rate limit with special message"
 [rate_limit.method_overrides.eth_foobar]
 limit = 1
 interval = "1s"
+
+[rate_limit.method_overrides.eth_baz]
+limit = 1
+interval = "1s"
+global = true
\ No newline at end of file

proxyd/server.go

@@ -56,6 +56,7 @@ type Server struct {
 	senderLim              FrontendRateLimiter
 	limExemptOrigins       []*regexp.Regexp
 	limExemptUserAgents    []*regexp.Regexp
+	globallyLimitedMethods map[string]bool
 	rpcServer              *http.Server
 	wsServer               *http.Server
 	cache                  RPCCache
@@ -133,12 +134,17 @@ func NewServer(
 	}
 
 	overrideLims := make(map[string]FrontendRateLimiter)
+	globalMethodLims := make(map[string]bool)
 	for method, override := range rateLimitConfig.MethodOverrides {
 		var err error
 		overrideLims[method] = limiterFactory(time.Duration(override.Interval), override.Limit, method)
 		if err != nil {
 			return nil, err
 		}
+
+		if override.Global {
+			globalMethodLims[method] = true
+		}
 	}
 	var senderLim FrontendRateLimiter
 	if senderRateLimitConfig.Enabled {
@@ -163,6 +169,7 @@ func NewServer(
 		},
 		mainLim:                mainLim,
 		overrideLims:           overrideLims,
+		globallyLimitedMethods: globalMethodLims,
 		senderLim:              senderLim,
 		limExemptOrigins:       limExemptOrigins,
 		limExemptUserAgents:    limExemptUserAgents,
@@ -243,7 +250,9 @@ func (s *Server) HandleRPC(w http.ResponseWriter, r *http.Request) {
 	}
 
 	isLimited := func(method string) bool {
-		if isUnlimitedOrigin || isUnlimitedUserAgent {
+		isGloballyLimitedMethod := s.isGlobalLimit(method)
+		fmt.Println(method, isGloballyLimitedMethod)
+		if !isGloballyLimitedMethod && (isUnlimitedOrigin || isUnlimitedUserAgent) {
 			return false
 		}
 
@@ -597,6 +606,10 @@ func (s *Server) isUnlimitedUserAgent(origin string) bool {
 	return false
 }
 
+func (s *Server) isGlobalLimit(method string) bool {
+	return s.globallyLimitedMethods[method]
+}
+
 func (s *Server) rateLimitSender(ctx context.Context, req *RPCReq) error {
 	var params []string
 	if err := json.Unmarshal(req.Params, &params); err != nil {