add expiry connection and automatic close

.gitignore

@@ -1 +1,2 @@
 grpcox
+log

config.env

@@ -0,0 +1,2 @@
+MAX_LIFE_CONN=10
+TICK_CLOSE_CONN=3

core/connection.go

@@ -0,0 +1,143 @@
+package core
+
+import (
+	"log"
+	"sync"
+	"time"
+)
+
+// ConnStore - connection store instance
+type ConnStore struct {
+	sync.RWMutex
+
+	conn map[string]*connection
+
+	// flag for auto garbage collector(close and cleanup expired connection)
+	activeGC bool
+	// controls gc intervals
+	gcTicker *time.Ticker
+	// gc stop signal
+	done chan struct{}
+}
+
+type connection struct {
+	// hold connection object
+	resource *Resource
+	// keep connect
+	keepAlive bool
+	// will automatically close connection
+	expired time.Time
+}
+
+// NewConnectionStore - constructor connection store
+func NewConnectionStore() *ConnStore {
+	return &ConnStore{
+		conn: make(map[string]*connection),
+	}
+}
+
+// StartGC - start gc ticker
+func (c *ConnStore) StartGC(interval time.Duration) {
+	if interval <= 0 {
+		return
+	}
+
+	c.activeGC = true
+
+	ticker := time.NewTicker(interval)
+	done := make(chan struct{})
+
+	c.Lock()
+	c.gcTicker = ticker
+	c.done = done
+	c.Unlock()
+
+	go func() {
+		for {
+			select {
+			case <-ticker.C:
+				c.Lock()
+				for key := range c.conn {
+					if c.isExpired(key) {
+						c.delete(key)
+						log.Printf("Connection %s expired and closed\n", key)
+					}
+				}
+				c.Unlock()
+			case <-done:
+				return
+			}
+		}
+	}()
+}
+
+// StopGC stops sweeping goroutine.
+func (c *ConnStore) StopGC() {
+	if c.activeGC {
+		c.Lock()
+		c.gcTicker.Stop()
+		c.gcTicker = nil
+		close(c.done)
+		c.done = nil
+		c.Unlock()
+	}
+}
+
+func (c *ConnStore) extend(key string, ttl time.Duration) {
+	conn := c.conn[key]
+	if conn != nil {
+		conn.extendConnection(ttl)
+	}
+}
+
+func (c *ConnStore) isExpired(key string) bool {
+	conn := c.conn[key]
+	if conn == nil {
+		return false
+	}
+	return !conn.keepAlive && conn.expired.Before(time.Now())
+}
+
+func (c *ConnStore) getAllConn() map[string]*connection {
+	return c.conn
+}
+
+func (c *ConnStore) delete(key string) {
+	conn := c.conn[key]
+	if conn != nil {
+		conn.close()
+		delete(c.conn, key)
+	}
+}
+
+func (c *ConnStore) addConnection(host string, res *Resource, ttl ...time.Duration) {
+	conn := &connection{
+		resource:  res,
+		keepAlive: true,
+	}
+
+	if len(ttl) > 0 {
+		conn.keepAlive = false
+		conn.expired = time.Now().Add(ttl[0])
+	}
+
+	c.conn[host] = conn
+}
+
+func (c *ConnStore) getConnection(host string) (res *Resource, found bool) {
+	conn, ok := c.conn[host]
+	if ok && conn.resource != nil {
+		found = true
+		res = conn.resource
+	}
+	return
+}
+
+func (conn *connection) extendConnection(ttl time.Duration) {
+	conn.keepAlive = false
+	conn.expired = time.Now().Add(ttl)
+}
+
+func (conn *connection) close() {
+	conn.resource.Close()
+}

core/grpcox.go

@@ -2,6 +2,8 @@ package core
 
 import (
 	"context"
+	"os"
+	"strconv"
 	"time"
 
 	"github.com/fullstorydev/grpcurl"
@@ -17,7 +19,8 @@ import (
 type GrpCox struct {
 	KeepAlive float64
 
-	activeConn map[string]*Resource
+	activeConn  *ConnStore
+	maxLifeConn time.Duration
 
 	// TODO : utilize below args
 	headers        []string
@@ -33,15 +36,33 @@ type GrpCox struct {
 
 // InitGrpCox constructor
 func InitGrpCox() *GrpCox {
-	return &GrpCox{
+	maxLife, tick := 10, 3
-		activeConn: make(map[string]*Resource),
+
+	if val, err := strconv.Atoi(os.Getenv("MAX_LIFE_CONN")); err == nil {
+		maxLife = val
 	}
+
+	if val, err := strconv.Atoi(os.Getenv("TICK_CLOSE_CONN")); err == nil {
+		tick = val
+	}
+
+	c := NewConnectionStore()
+	g := &GrpCox{
+		activeConn: c,
+	}
+
+	if maxLife > 0 && tick > 0 {
+		g.maxLifeConn = time.Duration(maxLife) * time.Minute
+		c.StartGC(time.Duration(tick) * time.Second)
+	}
+
+	return g
 }
 
 // GetResource - open resource to targeted grpc server
 func (g *GrpCox) GetResource(ctx context.Context, target string, plainText, isRestartConn bool) (*Resource, error) {
-	if conn, ok := g.activeConn[target]; ok {
+	if conn, ok := g.activeConn.getConnection(target); ok {
-		if !isRestartConn && conn.refClient != nil && conn.clientConn != nil {
+		if !isRestartConn && conn.isValid() {
 			return conn, nil
 		}
 		g.CloseActiveConns(target)
@@ -61,15 +82,16 @@ func (g *GrpCox) GetResource(ctx context.Context, target string, plainText, isRe
 	r.descSource = grpcurl.DescriptorSourceFromServer(ctx, r.refClient)
 	r.headers = h
 
-	g.activeConn[target] = r
+	g.activeConn.addConnection(target, r, g.maxLifeConn)
 	return r, nil
 }
 
 // GetActiveConns - get all saved active connection
 func (g *GrpCox) GetActiveConns(ctx context.Context) []string {
-	result := make([]string, len(g.activeConn))
+	active := g.activeConn.getAllConn()
+	result := make([]string, len(active))
 	i := 0
-	for k := range g.activeConn {
+	for k := range active {
 		result[i] = k
 		i++
 	}
@@ -79,19 +101,19 @@ func (g *GrpCox) GetActiveConns(ctx context.Context) []string {
 // CloseActiveConns - close conn by host or all
 func (g *GrpCox) CloseActiveConns(host string) error {
 	if host == "all" {
-		for k, v := range g.activeConn {
+		for k := range g.activeConn.getAllConn() {
-			v.Close()
+			g.activeConn.delete(k)
-			delete(g.activeConn, k)
 		}
 		return nil
 	}
 
-	if v, ok := g.activeConn[host]; ok {
+	g.activeConn.delete(host)
-		v.Close()
+	return nil
-		delete(g.activeConn, host)
 }
 
-	return nil
+// Extend extend connection based on setting max life
+func (g *GrpCox) Extend(host string) {
+	g.activeConn.extend(host, g.maxLifeConn)
 }
 
 func (g *GrpCox) dial(ctx context.Context, target string, plainText bool) (*grpc.ClientConn, error) {

core/resource.go

@@ -182,10 +182,15 @@ func (r *Resource) Close() {
 	case <-done:
 		return
 	case <-time.After(3 * time.Second):
+		log.Printf("Connection %s falied to close\n", r.clientConn.Target())
 		return
 	}
 }
 
+func (r *Resource) isValid() bool {
+	return r.refClient != nil && r.clientConn != nil
+}
+
 func (r *Resource) exit(code int) {
 	// to force reset before os exit
 	r.Close()

docker-compose.yml

@@ -6,3 +6,6 @@ services:
       - "6969:6969"
     volumes:
       - ./index:/index
+      - ./log:/log
+    env_file:
+      - config.env

grpcox.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"log"
 	"net/http"
+	"os"
 	"time"
 
 	"github.com/gorilla/mux"
@@ -11,6 +12,16 @@ import (
 )
 
 func main() {
+	// logging conf
+	f, err := os.OpenFile("log/grpcox.log", os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)
+	if err != nil {
+		log.Fatalf("error opening file: %v", err)
+	}
+	defer f.Close()
+	log.SetOutput(f)
+	log.SetFlags(log.LstdFlags | log.Lshortfile)
+
+	// start app
 	port := ":6969"
 	muxRouter := mux.NewRouter()
 	handler.Init(muxRouter)

handler/handler.go

@@ -81,6 +81,7 @@ func (h *Handler) getLists(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	h.g.Extend(host)
 	response(w, result)
 }
 
@@ -130,6 +131,7 @@ func (h *Handler) describeFunction(w http.ResponseWriter, r *http.Request) {
 		Template string `json:"template"`
 	}
 
+	h.g.Extend(host)
 	response(w, desc{
 		Schema:   result,
 		Template: template,
@@ -171,6 +173,7 @@ func (h *Handler) invokeFunction(w http.ResponseWriter, r *http.Request) {
 		Result string `json:"result"`
 	}
 
+	h.g.Extend(host)
 	response(w, invRes{
 		Time:   timer.String(),
 		Result: result,