rpcserver metrics (#30)

* rpcserver metrics

* rpcserver: add server name

go.mod

@@ -3,6 +3,7 @@ module github.com/flashbots/go-utils
 go 1.20
 
 require (
+	github.com/VictoriaMetrics/metrics v1.35.1
 	github.com/ethereum/go-ethereum v1.13.14
 	github.com/google/uuid v1.3.1
 	github.com/sirupsen/logrus v1.9.3
@@ -34,6 +35,8 @@ require (
 	github.com/supranational/blst v0.3.11 // indirect
 	github.com/tklauser/go-sysconf v0.3.12 // indirect
 	github.com/tklauser/numcpus v0.6.1 // indirect
+	github.com/valyala/fastrand v1.1.0 // indirect
+	github.com/valyala/histogram v1.2.0 // indirect
 	go.uber.org/multierr v1.11.0 // indirect
 	golang.org/x/mod v0.14.0 // indirect
 	golang.org/x/sync v0.5.0 // indirect

go.sum

@@ -4,6 +4,8 @@ github.com/Microsoft/go-winio v0.6.1/go.mod h1:LRdKpFKfdobln8UmuiYcKPot9D2v6svN5
 github.com/StackExchange/wmi v1.2.1 h1:VIkavFPXSjcnS+O8yTq7NI32k0R5Aj+v39y29VYDOSA=
 github.com/StackExchange/wmi v1.2.1/go.mod h1:rcmrprowKIVzvc+NUiLncP2uuArMWLCbu9SBzvHz7e8=
 github.com/VictoriaMetrics/fastcache v1.12.1 h1:i0mICQuojGDL3KblA7wUNlY5lOK6a4bwt3uRKnkZU40=
+github.com/VictoriaMetrics/metrics v1.35.1 h1:o84wtBKQbzLdDy14XeskkCZih6anG+veZ1SwJHFGwrU=
+github.com/VictoriaMetrics/metrics v1.35.1/go.mod h1:r7hveu6xMdUACXvB8TYdAj8WEsKzWB0EkpJN+RDtOf8=
 github.com/benbjohnson/clock v1.3.0 h1:ip6w0uFQkncKQ979AypyG0ER7mqUSBdKLOgAle/AT8A=
 github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
 github.com/bits-and-blooms/bitset v1.10.0 h1:ePXTeiPEazB5+opbv5fr8umg2R/1NlzgDsyepwsSr88=
@@ -106,6 +108,10 @@ github.com/tklauser/numcpus v0.6.1 h1:ng9scYS7az0Bk4OZLvrNXNSAO2Pxr1XXRAPyjhIx+F
 github.com/tklauser/numcpus v0.6.1/go.mod h1:1XfjsgE2zo8GVw7POkMbHENHzVg3GzmoZ9fESEdAacY=
 github.com/tyler-smith/go-bip39 v1.1.0 h1:5eUemwrMargf3BSLRRCalXT93Ns6pQJIjYQN2nyfOP8=
 github.com/urfave/cli/v2 v2.25.7 h1:VAzn5oq403l5pHjc4OhD54+XGO9cdKVL/7lDjF+iKUs=
+github.com/valyala/fastrand v1.1.0 h1:f+5HkLW4rsgzdNoleUOB69hyT9IlD2ZQh9GyDMfb5G8=
+github.com/valyala/fastrand v1.1.0/go.mod h1:HWqCzkrkg6QXT8V2EXWvXCoow7vLwOFN002oeRzjapQ=
+github.com/valyala/histogram v1.2.0 h1:wyYGAZZt3CpwUiIb9AU/Zbllg1llXyrtApRS815OLoQ=
+github.com/valyala/histogram v1.2.0/go.mod h1:Hb4kBwb4UxsaNbbbh+RRz8ZR6pdodR57tzWUS3BUzXY=
 github.com/xrash/smetrics v0.0.0-20201216005158-039620a65673 h1:bAn7/zixMGCfxrRTfdpNzjtPYqr8smhKouy9mxVdGPU=
 go.uber.org/atomic v1.11.0 h1:ZvwS0R+56ePWxUNi+Atn9dWONBPp/AUETXlHW0DxSjE=
 go.uber.org/atomic v1.11.0/go.mod h1:LUxbIzbOniOlMKjJjyPfpl4v+PKK2cNJn91OQbhoJI0=

rpcserver/jsonrpc_server.go

@@ -14,6 +14,7 @@ import (
 	"log/slog"
 	"net/http"
 	"strings"
+	"time"
 
 	"github.com/ethereum/go-ethereum/common"
 	"github.com/flashbots/go-utils/signature"
@@ -75,6 +76,8 @@ type Methods map[string]any
 type JSONRPCHandlerOpts struct {
 	// Logger, can be nil
 	Log *slog.Logger
+	// Server name. Used to separate logs and metrics when having multiple servers in one binary.
+	ServerName string
 	// Max size of the request payload
 	MaxRequestBodySizeBytes int64
 	// If true payload signature from X-Flashbots-Signature will be verified
@@ -120,9 +123,10 @@ func (h *JSONRPCHandler) writeJSONRPCResponse(w http.ResponseWriter, response js
 	w.Header().Set("Content-Type", "application/json")
 	if err := json.NewEncoder(w).Encode(response); err != nil {
 		if h.Log != nil {
-			h.Log.Error("failed to marshall response", slog.Any("error", err))
+			h.Log.Error("failed to marshall response", slog.Any("error", err), slog.String("serverName", h.ServerName))
 		}
 		http.Error(w, errMarshalResponse, http.StatusInternalServerError)
+		incInternalErrors(h.ServerName)
 		return
 	}
 }
@@ -142,15 +146,25 @@ func (h *JSONRPCHandler) writeJSONRPCError(w http.ResponseWriter, id any, code i
 }
 
 func (h *JSONRPCHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	startAt := time.Now()
+	methodForMetrics := unknownMethodLabel
+
 	ctx := r.Context()
 
+	defer func() {
+		incRequestCount(methodForMetrics, h.ServerName)
+		incRequestDuration(methodForMetrics, time.Since(startAt).Milliseconds(), h.ServerName)
+	}()
+
 	if r.Method != http.MethodPost {
 		http.Error(w, errMethodNotAllowed, http.StatusMethodNotAllowed)
+		incIncorrectRequest(h.ServerName)
 		return
 	}
 
 	if r.Header.Get("Content-Type") != "application/json" {
 		http.Error(w, errWrongContentType, http.StatusUnsupportedMediaType)
+		incIncorrectRequest(h.ServerName)
 		return
 	}
 
@@ -159,6 +173,7 @@ func (h *JSONRPCHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	if err != nil {
 		msg := fmt.Sprintf("request body is too big, max size: %d", h.MaxRequestBodySizeBytes)
 		h.writeJSONRPCError(w, nil, CodeInvalidRequest, msg)
+		incIncorrectRequest(h.ServerName)
 		return
 	}
 
@@ -167,6 +182,7 @@ func (h *JSONRPCHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		signer, err := signature.Verify(signatureHeader, body)
 		if err != nil {
 			h.writeJSONRPCError(w, nil, CodeInvalidRequest, err.Error())
+			incIncorrectRequest(h.ServerName)
 			return
 		}
 		ctx = context.WithValue(ctx, signerKey{}, signer)
@@ -176,11 +192,13 @@ func (h *JSONRPCHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	var req jsonRPCRequest
 	if err := json.Unmarshal(body, &req); err != nil {
 		h.writeJSONRPCError(w, nil, CodeParseError, err.Error())
+		incIncorrectRequest(h.ServerName)
 		return
 	}
 
 	if req.JSONRPC != "2.0" {
 		h.writeJSONRPCError(w, req.ID, CodeParseError, "invalid jsonrpc version")
+		incIncorrectRequest(h.ServerName)
 		return
 	}
 	if req.ID != nil {
@@ -189,6 +207,8 @@ func (h *JSONRPCHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		case string, int, int8, int16, int32, int64, uint, uint8, uint16, uint32, uint64, float32, float64:
 		default:
 			h.writeJSONRPCError(w, req.ID, CodeParseError, "invalid id type")
+			incIncorrectRequest(h.ServerName)
+			return
 		}
 	}
 
@@ -210,6 +230,7 @@ func (h *JSONRPCHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 		if origin != "" {
 			if len(origin) > maxOriginIDLength {
 				h.writeJSONRPCError(w, req.ID, CodeInvalidRequest, "x-flashbots-origin header is too long")
+				incIncorrectRequest(h.ServerName)
 				return
 			}
 			ctx = context.WithValue(ctx, originKey{}, origin)
@@ -220,19 +241,23 @@ func (h *JSONRPCHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	method, ok := h.methods[req.Method]
 	if !ok {
 		h.writeJSONRPCError(w, req.ID, CodeMethodNotFound, "method not found")
+		incIncorrectRequest(h.ServerName)
 		return
 	}
+	methodForMetrics = req.Method
 
 	// call method
 	result, err := method.call(ctx, req.Params)
 	if err != nil {
 		h.writeJSONRPCError(w, req.ID, CodeCustomError, err.Error())
+		incRequestErrorCount(methodForMetrics, h.ServerName)
 		return
 	}
 
 	marshaledResult, err := json.Marshal(result)
 	if err != nil {
 		h.writeJSONRPCError(w, req.ID, CodeInternalError, err.Error())
+		incInternalErrors(h.ServerName)
 		return
 	}
 

rpcserver/metrics.go

@@ -0,0 +1,51 @@
+package rpcserver
+
+import (
+	"fmt"
+
+	"github.com/VictoriaMetrics/metrics"
+)
+
+const (
+	// we use unknown method label for methods that server does not support because otherwise
+	// users can create arbitrary number of metrics
+	unknownMethodLabel = "unknown"
+
+	// incremented when user made incorrect request
+	incorrectRequestCounter = `goutils_rpcserver_incorrect_request_total{server_name="%s"}`
+
+	// incremented when server has a bug (e.g. can't marshall response)
+	internalErrorsCounter = `goutils_rpcserver_internal_errors_total{server_name="%s"}`
+
+	// incremented when request comes in
+	requestCountLabel = `goutils_rpcserver_request_count{method="%s",server_name="%s"}`
+	// incremented when handler method returns JSONRPC error
+	errorCountLabel = `goutils_rpcserver_error_count{method="%s",server_name="%s"}`
+	// total duration of the request
+	requestDurationLabel = `goutils_rpcserver_request_duration_milliseconds{method="%s",server_name="%s"}`
+)
+
+func incRequestCount(method, serverName string) {
+	l := fmt.Sprintf(requestCountLabel, method, serverName)
+	metrics.GetOrCreateCounter(l).Inc()
+}
+
+func incIncorrectRequest(serverName string) {
+	l := fmt.Sprintf(incorrectRequestCounter, serverName)
+	metrics.GetOrCreateCounter(l).Inc()
+}
+
+func incRequestErrorCount(method, serverName string) {
+	l := fmt.Sprintf(errorCountLabel, method, serverName)
+	metrics.GetOrCreateCounter(l).Inc()
+}
+
+func incRequestDuration(method string, duration int64, serverName string) {
+	l := fmt.Sprintf(requestDurationLabel, method, serverName)
+	metrics.GetOrCreateSummary(l).Update(float64(duration))
+}
+
+func incInternalErrors(serverName string) {
+	l := fmt.Sprintf(internalErrorsCounter, serverName)
+	metrics.GetOrCreateCounter(l).Inc()
+}