fix(metrics): add http server for metrics.

config/config.go

@@ -8,6 +8,7 @@ import (
 	"github.com/dezh-tech/immortal/handler"
 	"github.com/dezh-tech/immortal/relay/redis"
 	"github.com/dezh-tech/immortal/server/grpc"
+	"github.com/dezh-tech/immortal/server/http"
 	"github.com/dezh-tech/immortal/server/websocket"
 	"github.com/joho/godotenv"
 	"gopkg.in/yaml.v3"
@@ -21,6 +22,7 @@ type Config struct {
 	Database        database.Config  `yaml:"database"`
 	RedisConf       redis.Config     `yaml:"redis"`
 	GRPCServer      grpc.Config      `yaml:"grpc_server"`
+	Metrics         http.Config      `yaml:"metrics"`
 	Handler         handler.Config
 }
 

config/config.yml

@@ -11,7 +11,7 @@ environment: "prod"
 # ws_server contains information about websocket server.
 ws_server:
   # bind is the IP address to be bind and listen on.
-  # default is local host.
+  # default is 0.0.0.0.
   bind: "0.0.0.0"
 
   # port is websocket port to be listen on.
@@ -21,13 +21,27 @@ ws_server:
 # grpc_server contains information about grpc server.
 grpc_server:
   # bind is the IP address to be bind and listen on.
-  # default is local host.
+  # default is 0.0.0.0.
   bind: "0.0.0.0"
 
   # port is grpc port to be listen on.
   # default is 50050.
   port: 50050
 
+# metrics contains information about prometheus metrics https server.
+metrics:
+  # bind is the IP address to be bind and listen on.
+  # default is 0.0.0.0.
+  bind: "0.0.0.0"
+
+  # port is grpc port to be listen on.
+  # default is 9090.
+  port: 9090
+
+  # enable or disable metrics service.
+  # default is disabled.
+  enable: false
+
 # kraken contains information about connection with kraken instance.
 kraken:
   # IP address of kraken instance.

go.mod

@@ -27,6 +27,7 @@ require (
 	github.com/decred/dcrd/dcrec/secp256k1/v4 v4.3.0 // indirect
 	github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f // indirect
 	github.com/golang/snappy v0.0.4 // indirect
+	github.com/gorilla/mux v1.8.1
 	github.com/josharian/intern v1.0.0 // indirect
 	github.com/klauspost/compress v1.17.11 // indirect
 	github.com/kr/text v0.2.0 // indirect

go.sum

@@ -31,6 +31,8 @@ github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=
 github.com/google/go-cmp v0.6.0/go.mod h1:17dUlkBOakJ0+DkrSSNjCkIjxS6bF9zb3elmeNGIjoY=
 github.com/google/uuid v1.6.0 h1:NIvaJDMOsjHA8n1jAhLSgzrAzy1Hgr+hNrb57e+94F0=
 github.com/google/uuid v1.6.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+yHo=
+github.com/gorilla/mux v1.8.1 h1:TuBL49tXwgrFYWhqrNgrUNEY92u81SPhu7sTdzQEiWY=
+github.com/gorilla/mux v1.8.1/go.mod h1:AKf9I4AEqPTmMytcMc0KkNouC66V3BtZ4qD5fmWSiMQ=
 github.com/gorilla/websocket v1.5.3 h1:saDtZ6Pbx/0u+bgYQ3q96pZgCzfhKXGPqt7kZ72aNNg=
 github.com/gorilla/websocket v1.5.3/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
 github.com/joho/godotenv v1.5.1 h1:7eLL/+HRGLY0ldzfGMeQkb7vMd0as4CfYvUVzLqw0N0=
@@ -43,6 +45,8 @@ github.com/kr/pretty v0.3.1 h1:flRD4NNwYAUpkphVc1HcthR4KEIFJ65n8Mw5qdRn3LE=
 github.com/kr/pretty v0.3.1/go.mod h1:hoEshYVHaxMs3cyo3Yncou5ZscifuDolrwPKZanG3xk=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
+github.com/kylelemons/godebug v1.1.0 h1:RPNrshWIDI6G2gRW9EHilWtl7Z6Sb1BR0xunSBf0SNc=
+github.com/kylelemons/godebug v1.1.0/go.mod h1:9/0rRGxNHcop5bhtWyNeEfOS8JIWk580+fNqagV/RAw=
 github.com/mailru/easyjson v0.7.7 h1:UGYAvKxe3sBsEDzO8ZeWOSlIQfWFlxbzLZe7hwFURr0=
 github.com/mailru/easyjson v0.7.7/go.mod h1:xzfreul335JAWq5oZzymOObrkdz5UnU4kGfJJLY9Nlc=
 github.com/montanaflynn/stats v0.7.1 h1:etflOAAHORrCC44V+aR6Ftzort912ZU+YLiSTuV8eaE=

relay/relay.go

@@ -13,6 +13,7 @@ import (
 	"github.com/dezh-tech/immortal/metrics"
 	"github.com/dezh-tech/immortal/relay/redis"
 	"github.com/dezh-tech/immortal/server/grpc"
+	"github.com/dezh-tech/immortal/server/http"
 	"github.com/dezh-tech/immortal/server/websocket"
 )
 
@@ -21,6 +22,7 @@ type Relay struct {
 	config          config.Config
 	websocketServer *websocket.Server
 	grpcServer      *grpc.Server
+	httpServer      *http.Server
 	database        *database.Database
 	redis           *redis.Redis
 }
@@ -73,11 +75,17 @@ func New(cfg *config.Config) (*Relay, error) {
 
 	gs := grpc.New(&cfg.GRPCServer, r, db, time.Now())
 
+	hs, err := http.New(cfg.Metrics)
+	if err != nil {
+		return nil, err
+	}
+
 	return &Relay{
 		config:          *cfg,
 		websocketServer: ws,
 		database:        db,
 		redis:           r,
+		httpServer:      hs,
 		grpcServer:      gs,
 	}, nil
 }
@@ -99,6 +107,14 @@ func (r *Relay) Start() chan error {
 		}
 	}()
 
+	if r.config.Metrics.Enable {
+		go func() {
+			if err := r.httpServer.Start(); err != nil {
+				errCh <- err
+			}
+		}()
+	}
+
 	return errCh
 }
 
@@ -114,5 +130,11 @@ func (r *Relay) Stop() error {
 		return err
 	}
 
+	if r.config.Metrics.Enable {
+		if err := r.httpServer.Start(); err != nil {
+			return err
+		}
+	}
+
 	return r.database.Stop()
 }

server/http/config.go

@@ -0,0 +1,7 @@
+package http
+
+type Config struct {
+	Bind   string `yaml:"bind"`
+	Port   uint16 `yaml:"port"`
+	Enable bool   `yaml:"enable"`
+}

server/http/server.go

@@ -0,0 +1,33 @@
+package http
+
+import (
+	"net"
+	"net/http"
+	"strconv"
+
+	"github.com/gorilla/mux"
+	"github.com/prometheus/client_golang/prometheus/promhttp"
+)
+
+type Server struct {
+	router *mux.Router
+	config Config
+}
+
+func New(cfg Config) (*Server, error) {
+	r := mux.NewRouter()
+
+	s := &Server{
+		router: r,
+		config: cfg,
+	}
+
+	r.Handle("/metrics", promhttp.Handler()).Methods("GET")
+
+	return s, nil
+}
+
+func (s *Server) Start() error {
+	return http.ListenAndServe(net.JoinHostPort(s.config.Bind, //nolint
+		strconv.Itoa(int(s.config.Port))), s.router)
+}

server/websocket/event_handler.go

@@ -187,7 +187,7 @@ func (s *Server) handleEvent(conn *websocket.Conn, m message.Message) {
 		log.Printf("error: checking bloom filter: %s", err.Error())
 	}
 
-	// todo::: can we run goroutines per client?
+	// todo::: should we run goroutines per client?
 	for conn, client := range s.conns {
 		client.Lock()
 		for id, filters := range client.subs {