add prometheus-middlewares for http and ws endpoint

pkg/rpc/ws.go

@@ -0,0 +1,46 @@
+package rpc
+
+import (
+	"net"
+
+	"github.com/ethereum/go-ethereum/rpc"
+	log "github.com/sirupsen/logrus"
+	"github.com/vulcanize/ipld-eth-server/pkg/prom"
+)
+
+// StartWSEndpoint starts a websocket endpoint.
+func StartWSEndpoint(endpoint string, apis []rpc.API, modules []string, wsOrigins []string, exposeAll bool) (net.Listener, *rpc.Server, error) {
+	if bad, available := checkModuleAvailability(modules, apis); len(bad) > 0 {
+		log.Error("Unavailable modules in WS API list", "unavailable", bad, "available", available)
+	}
+	// Generate the whitelist based on the allowed modules
+	whitelist := make(map[string]bool)
+	for _, module := range modules {
+		whitelist[module] = true
+	}
+	// Register all the APIs exposed by the services
+	handler := rpc.NewServer()
+	for _, api := range apis {
+		if exposeAll || whitelist[api.Namespace] || (len(whitelist) == 0 && api.Public) {
+			if err := handler.RegisterName(api.Namespace, api.Service); err != nil {
+				return nil, nil, err
+			}
+			log.Debug("WebSocket registered", "service", api.Service, "namespace", api.Namespace)
+		}
+	}
+	// All APIs registered, start the HTTP listener
+	var (
+		listener net.Listener
+		err      error
+	)
+	if listener, err = net.Listen("tcp", endpoint); err != nil {
+		return nil, nil, err
+	}
+
+	wsServer := rpc.NewWSServer(wsOrigins, handler)
+	wsServer.Handler = prom.WSMiddleware(wsServer.Handler)
+	go wsServer.Serve(listener)
+
+	return listener, handler, err
+
+}