whitelist methods

benchmark-proxy/main.go

@@ -248,6 +248,12 @@ type ChainHead struct {
 	Error       string    // Last error if any
 }
 
+// MethodRouting contains configuration for method routing decisions
+type MethodRouting struct {
+	SecondaryWhitelist map[string]bool // Methods allowed on secondary backends
+	PreferSecondary    map[string]bool // Methods that should prefer secondary backends
+}
+
 // RequestInfo contains parsed information about a JSON-RPC request
 type RequestInfo struct {
 	Method    string
@@ -2196,6 +2202,21 @@ func isNullResponse(respBody []byte) bool {
 	return string(response.Result) == "null"
 }
 
+// methodShouldWaitOnSecondaryError returns true if we should wait for primary
+// when secondary returns an error response
+func methodShouldWaitOnSecondaryError(method string) bool {
+	// Methods where secondary errors might be transient and primary could succeed
+	waitOnErrorMethods := map[string]bool{
+		"eth_call":             true, // State execution - secondary might be behind or have issues
+		"eth_estimateGas":      true, // Similar to eth_call
+		"trace_call":           true, // Tracing calls
+		"debug_traceCall":      true, // Debug tracing
+		"eth_createAccessList": true, // Access list creation
+	}
+
+	return waitOnErrorMethods[method]
+}
+
 // flushingResponseWriter wraps http.ResponseWriter to flush after every write
 type flushingResponseWriter struct {
 	http.ResponseWriter
@@ -2210,6 +2231,89 @@ func (f *flushingResponseWriter) Write(p []byte) (n int, err error) {
 	return
 }
 
+// peekingReader wraps a reader to peek at the first N bytes and detect null or error responses
+type peekingReader struct {
+	r         io.Reader
+	buf       []byte
+	bufPos    int
+	isNull    bool
+	hasError  bool
+	checkDone bool
+	peekSize  int
+}
+
+func newPeekingReader(r io.Reader, peekSize int) *peekingReader {
+	return &peekingReader{
+		r:        r,
+		buf:      make([]byte, 0, peekSize),
+		peekSize: peekSize,
+	}
+}
+
+func (pr *peekingReader) Read(p []byte) (n int, err error) {
+	// If we haven't finished checking yet
+	if !pr.checkDone && len(pr.buf) < pr.peekSize {
+		// Read more data into our buffer
+		tempBuf := make([]byte, pr.peekSize-len(pr.buf))
+		readN, readErr := pr.r.Read(tempBuf)
+		if readN > 0 {
+			pr.buf = append(pr.buf, tempBuf[:readN]...)
+		}
+
+		// Check if we have enough data or hit EOF
+		if len(pr.buf) >= pr.peekSize || readErr == io.EOF {
+			pr.checkDone = true
+			// Check for null response pattern
+			pr.detectPatterns()
+		}
+
+		if readErr != nil && readErr != io.EOF {
+			return 0, readErr
+		}
+	}
+
+	// Serve data from buffer first
+	if pr.bufPos < len(pr.buf) {
+		n = copy(p, pr.buf[pr.bufPos:])
+		pr.bufPos += n
+		return n, nil
+	}
+
+	// Then serve from underlying reader
+	return pr.r.Read(p)
+}
+
+func (pr *peekingReader) detectPatterns() {
+	// Look for patterns indicating null result or errors in JSON-RPC response
+	bufStr := string(pr.buf)
+
+	// Remove whitespace for easier pattern matching
+	compactStr := strings.ReplaceAll(bufStr, " ", "")
+	compactStr = strings.ReplaceAll(compactStr, "\n", "")
+	compactStr = strings.ReplaceAll(compactStr, "\r", "")
+	compactStr = strings.ReplaceAll(compactStr, "\t", "")
+
+	// Check for null result
+	pr.isNull = strings.Contains(compactStr, `"result":null`)
+
+	// Check for JSON-RPC errors
+	pr.hasError = strings.Contains(compactStr, `"error":`) && !strings.Contains(compactStr, `"error":null`)
+
+	// Log what we found for debugging
+	if pr.isNull || pr.hasError {
+		log.Printf("Detected short response pattern - null: %v, error: %v, buffer preview: %s",
+			pr.isNull, pr.hasError, strings.ReplaceAll(bufStr[:minInt(len(bufStr), 80)], "\n", " "))
+	}
+}
+
+func (pr *peekingReader) IsNull() bool {
+	return pr.isNull
+}
+
+func (pr *peekingReader) HasError() bool {
+	return pr.hasError
+}
+
 func main() {
 	// Get configuration from environment variables
 	listenAddr := getEnv("LISTEN_ADDR", ":8080")
@@ -2224,6 +2328,10 @@ func main() {
 	minDelayBufferStr := getEnv("MIN_DELAY_BUFFER", "2") // Default 2ms buffer
 	probeMethodsStr := getEnv("PROBE_METHODS", "eth_blockNumber,net_version,eth_chainId")
 
+	// Method routing configuration
+	secondaryWhitelistStr := getEnv("SECONDARY_WHITELIST", "") // Methods allowed on secondary
+	preferSecondaryStr := getEnv("PREFER_SECONDARY", "")       // Methods that should prefer secondary
+
 	summaryInterval, err := strconv.Atoi(summaryIntervalStr)
 	if err != nil {
 		log.Printf("Invalid SUMMARY_INTERVAL, using default of 60 seconds")
@@ -2242,6 +2350,32 @@ func main() {
 		minDelayBuffer = 2
 	}
 
+	// Parse method routing configuration
+	methodRouting := &MethodRouting{
+		SecondaryWhitelist: make(map[string]bool),
+		PreferSecondary:    make(map[string]bool),
+	}
+
+	// Parse whitelist
+	if secondaryWhitelistStr != "" {
+		whitelist := strings.Split(secondaryWhitelistStr, ",")
+		for _, method := range whitelist {
+			methodRouting.SecondaryWhitelist[strings.TrimSpace(method)] = true
+		}
+		log.Printf("Secondary whitelist: %v", whitelist)
+	}
+
+	// Parse prefer secondary list
+	if preferSecondaryStr != "" {
+		preferList := strings.Split(preferSecondaryStr, ",")
+		for _, method := range preferList {
+			methodRouting.PreferSecondary[strings.TrimSpace(method)] = true
+			// Also add to whitelist automatically
+			methodRouting.SecondaryWhitelist[strings.TrimSpace(method)] = true
+		}
+		log.Printf("Prefer secondary for methods: %v", preferList)
+	}
+
 	// Create stats collector for periodic summaries
 	statsCollector := NewStatsCollector(time.Duration(summaryInterval)*time.Second, secondaryBackendsStr != "")
 
@@ -2339,14 +2473,14 @@ func main() {
 			handleWebSocketRequest(w, r, backends, client, &upgrader, statsCollector)
 		} else {
 			// Handle regular HTTP request
-			handleRequest(w, r, backends, client, enableDetailedLogs == "true", statsCollector, secondaryProbe, chainHeadMonitor)
+			handleRequest(w, r, backends, client, enableDetailedLogs == "true", statsCollector, secondaryProbe, chainHeadMonitor, methodRouting)
 		}
 	})
 
 	log.Fatal(http.ListenAndServe(listenAddr, nil))
 }
 
-func handleRequest(w http.ResponseWriter, r *http.Request, backends []Backend, client *http.Client, enableDetailedLogs bool, statsCollector *StatsCollector, secondaryProbe *SecondaryProbe, chainHeadMonitor *ChainHeadMonitor) {
+func handleRequest(w http.ResponseWriter, r *http.Request, backends []Backend, client *http.Client, enableDetailedLogs bool, statsCollector *StatsCollector, secondaryProbe *SecondaryProbe, chainHeadMonitor *ChainHeadMonitor, methodRouting *MethodRouting) {
 	startTime := time.Now()
 
 	// Create a context that will cancel after 35 seconds (5s buffer over backend timeout)
@@ -2407,6 +2541,29 @@ func handleRequest(w http.ResponseWriter, r *http.Request, backends []Backend, c
 			log.Printf("Method: %s%s", displayMethod, blockTagInfo)
 		}
 	}
+
+	// Check method routing configuration
+	if !batchInfo.IsBatch && methodRouting != nil {
+		// For single methods, check routing rules
+		method := displayMethod
+
+		// Check if this method prefers secondary backends
+		if methodRouting.PreferSecondary[method] {
+			if enableDetailedLogs {
+				log.Printf("Method %s configured to prefer secondary backends", method)
+			}
+		}
+
+		// Check if whitelist is configured and method is not in it
+		if len(methodRouting.SecondaryWhitelist) > 0 && !methodRouting.SecondaryWhitelist[method] {
+			// Method not in whitelist - force primary only
+			if enableDetailedLogs {
+				log.Printf("Method %s not in secondary whitelist - using primary only", method)
+			}
+			// This will be enforced in the backend loop
+		}
+	}
+
 	// Process backends with adaptive delay strategy
 	var wg sync.WaitGroup
 	var primaryWg sync.WaitGroup // Separate wait group for primary backend
@@ -2424,6 +2581,30 @@ func handleRequest(w http.ResponseWriter, r *http.Request, backends []Backend, c
 	primaryFailedFast := make(chan struct{}, 1)   // Signal when primary fails immediately
 
 	for _, backend := range backends {
+		// Method routing checks for secondary backends
+		if backend.Role == "secondary" && methodRouting != nil && !batchInfo.IsBatch {
+			method := displayMethod
+
+			// Check if whitelist is configured and method is not in it
+			if len(methodRouting.SecondaryWhitelist) > 0 && !methodRouting.SecondaryWhitelist[method] {
+				if enableDetailedLogs {
+					log.Printf("Skipping secondary backend %s for method %s (not in whitelist)", backend.Name, method)
+				}
+				continue
+			}
+		}
+
+		// Skip primary backend if method prefers secondary (and we have secondary backends available)
+		if backend.Role == "primary" && methodRouting != nil && !batchInfo.IsBatch {
+			method := displayMethod
+			if methodRouting.PreferSecondary[method] && len(backends) > 1 {
+				if enableDetailedLogs {
+					log.Printf("Skipping primary backend for method %s (configured to prefer secondary)", method)
+				}
+				continue
+			}
+		}
+
 		// Skip secondary backends for stateful methods
 		if isStateful && backend.Role != "primary" {
 			if enableDetailedLogs {
@@ -2489,6 +2670,18 @@ func handleRequest(w http.ResponseWriter, r *http.Request, backends []Backend, c
 
 			// If this is a secondary backend, wait for p75 delay
 			if b.Role != "primary" {
+				// Skip delay if this method prefers secondary backends
+				skipDelay := false
+				if methodRouting != nil && !batchInfo.IsBatch {
+					if methodRouting.PreferSecondary[displayMethod] {
+						skipDelay = true
+						if enableDetailedLogs {
+							log.Printf("Secondary backend %s starting immediately for method %s (configured to prefer secondary)", b.Name, displayMethod)
+						}
+					}
+				}
+
+				if !skipDelay {
 					// Get backend-specific delay
 					var backendSpecificDelay time.Duration
 					if batchInfo.IsBatch {
@@ -2529,6 +2722,7 @@ func handleRequest(w http.ResponseWriter, r *http.Request, backends []Backend, c
 						}
 					}
 				}
+			}
 
 			// Create a new request (no longer using context for cancellation)
 			backendReq, err := http.NewRequest(r.Method, b.URL, bytes.NewReader(body))
@@ -2617,22 +2811,101 @@ func handleRequest(w http.ResponseWriter, r *http.Request, backends []Backend, c
 
 			// CRITICAL FIX 2: Check for null responses from secondary backends for certain methods
 			if b.Role == "secondary" && resp.StatusCode == 200 && methodMightReturnNull(displayMethod) {
-				// Need to read the body to check if it's null
-				bodyBytes, err := io.ReadAll(resp.Body)
-				resp.Body.Close() // Close the original body
+				// Check Content-Length first - null responses are typically very short
+				contentLength := resp.Header.Get("Content-Length")
+				if contentLength != "" {
+					length, err := strconv.Atoi(contentLength)
+					if err == nil && length < 100 { // Null responses are typically < 100 bytes
+						// This is suspiciously short, likely a null response
+						// Create a peeking reader to confirm
+						peeker := newPeekingReader(resp.Body, 100)
+						resp.Body = io.NopCloser(peeker)
 
-				if err == nil && isNullResponse(bodyBytes) {
-					// Secondary returned null - don't let it win the race
+						// Read a bit to trigger null detection
+						smallBuf := make([]byte, 1)
+						peeker.Read(smallBuf)
+
+						if peeker.IsNull() {
+							// Confirmed null response - don't let secondary win
+							if enableDetailedLogs {
+								log.Printf("Secondary backend %s returned null for %s (Content-Length: %s) - waiting for primary",
+									b.Name, displayMethod, contentLength)
+							}
+							// Close the response body
+							resp.Body.Close()
+							return
+						}
+						// Not null, continue with normal flow
+					}
+				} else {
+					// No Content-Length header, use peeking reader anyway for safety
+					peeker := newPeekingReader(resp.Body, 200) // Peek at first 200 bytes
+					resp.Body = io.NopCloser(peeker)
+
+					// Read a bit to trigger null detection
+					smallBuf := make([]byte, 1)
+					peeker.Read(smallBuf)
+
+					if peeker.IsNull() {
+						// Confirmed null response - don't let secondary win
 						if enableDetailedLogs {
 							log.Printf("Secondary backend %s returned null for %s - waiting for primary",
 								b.Name, displayMethod)
 						}
+						// Close the response body
+						resp.Body.Close()
 						return
 					}
+				}
+			}
 
-				// Not null or couldn't read - recreate the body for potential use
-				if err == nil {
-					resp.Body = io.NopCloser(bytes.NewReader(bodyBytes))
+			// CRITICAL FIX 3: Check for error responses from secondary backends for certain methods
+			if b.Role == "secondary" && resp.StatusCode == 200 && methodShouldWaitOnSecondaryError(displayMethod) {
+				// Check Content-Length first - error responses are typically short
+				contentLength := resp.Header.Get("Content-Length")
+				if contentLength != "" {
+					length, err := strconv.Atoi(contentLength)
+					if err == nil && length < 500 { // Error responses are typically < 500 bytes
+						// This might be an error response
+						// Create a peeking reader to confirm
+						peeker := newPeekingReader(resp.Body, 500)
+						resp.Body = io.NopCloser(peeker)
+
+						// Read a bit to trigger error detection
+						smallBuf := make([]byte, 1)
+						peeker.Read(smallBuf)
+
+						if peeker.HasError() {
+							// Confirmed error response - don't let secondary win
+							if enableDetailedLogs {
+								log.Printf("Secondary backend %s returned JSON-RPC error for %s (Content-Length: %s) - waiting for primary",
+									b.Name, displayMethod, contentLength)
+							}
+							// Close the response body
+							resp.Body.Close()
+							return
+						}
+						// Not an error, continue with normal flow
+					}
+				} else {
+					// No Content-Length header, use peeking reader anyway for safety
+					peeker := newPeekingReader(resp.Body, 500) // Peek at first 500 bytes
+					resp.Body = io.NopCloser(peeker)
+
+					// Read a bit to trigger error detection
+					smallBuf := make([]byte, 1)
+					peeker.Read(smallBuf)
+
+					if peeker.HasError() {
+						// Confirmed error response - don't let secondary win
+						if enableDetailedLogs {
+							log.Printf("Secondary backend %s returned JSON-RPC error for %s - waiting for primary",
+								b.Name, displayMethod)
+						}
+						// Close the response body
+						resp.Body.Close()
+						return
+					}
 				}
 			}