From f14a7046913e260c8f9fcd2ab981341f6283345f Mon Sep 17 00:00:00 2001
From: TeoV <teofil.voivozeanu@itsyscom.com>
Date: Thu, 28 May 2020 12:06:12 +0300
Subject: [PATCH] Add lazy connect when get dispatcher host from database

---
 dispatchers/attributes_it_test.go | 44 +++++++++++++++++++++++++++++++
 engine/datamanager.go             |  4 +--
 utils/errors.go                   |  9 ++++---
 3 files changed, 52 insertions(+), 5 deletions(-)

diff --git a/dispatchers/attributes_it_test.go b/dispatchers/attributes_it_test.go
index b9da25a96..cd5358717 100755
--- a/dispatchers/attributes_it_test.go
+++ b/dispatchers/attributes_it_test.go
@@ -31,6 +31,7 @@ import (
 
 var sTestsDspAttr = []func(t *testing.T){
 	testDspAttrPingFailover,
+	testDspAttrPingFailover2,
 	testDspAttrGetAttrFailover,
 	testDspAttrGetAttrRoundRobin,
 
@@ -132,6 +133,49 @@ func testDspAttrPingFailover(t *testing.T) {
 	}
 }
 
+func testDspAttrPingFailover2(t *testing.T) {
+	var reply string
+	if err := allEngine.RPC.Call(utils.AttributeSv1Ping, new(utils.CGREvent), &reply); err != nil {
+		t.Error(err)
+	} else if reply != utils.Pong {
+		t.Errorf("Received: %s", reply)
+	}
+	reply = ""
+	if err := allEngine2.RPC.Call(utils.AttributeSv1Ping, new(utils.CGREvent), &reply); err != nil {
+		t.Error(err)
+	} else if reply != utils.Pong {
+		t.Errorf("Received: %s", reply)
+	}
+	reply = ""
+	ev := utils.CGREventWithArgDispatcher{
+		CGREvent: &utils.CGREvent{
+			Tenant: "cgrates.org",
+		},
+		ArgDispatcher: &utils.ArgDispatcher{
+			APIKey: utils.StringPointer("attr12345"),
+		},
+	}
+	allEngine.stopEngine(t) // stop the engine and the call should go to the second engine
+	if err := dispEngine.RPC.Call(utils.AttributeSv1Ping, &ev, &reply); err != nil {
+		t.Error(err)
+	} else if reply != utils.Pong {
+		t.Errorf("Received: %s", reply)
+	}
+	allEngine2.stopEngine(t)
+	reply = ""
+	if err := dispEngine.RPC.Call(utils.AttributeSv1Ping, &ev, &reply); err == nil {
+		t.Errorf("Expected error but recived %v and reply %v\n", err, reply)
+	}
+	allEngine.startEngine(t)
+	allEngine2.startEngine(t)
+	reply = ""
+	if err := dispEngine.RPC.Call(utils.AttributeSv1Ping, &ev, &reply); err != nil {
+		t.Error(err)
+	} else if reply != utils.Pong {
+		t.Errorf("Received: %s", reply)
+	}
+}
+
 func testDspAttrGetAttrFailover(t *testing.T) {
 	args := &engine.AttrArgsProcessEvent{
 		Context: utils.StringPointer("simpleauth"),
diff --git a/engine/datamanager.go b/engine/datamanager.go
index 5e3123d19..3e00485b4 100644
--- a/engine/datamanager.go
+++ b/engine/datamanager.go
@@ -2172,13 +2172,13 @@ func (dm *DataManager) GetDispatcherHost(tenant, id string, cacheRead, cacheWrit
 	}
 	if cacheWrite {
 		cfg := config.CgrConfig()
-		if dH.rpcConn, err = NewRPCPool(
+		if dH.rpcConn, err = NewRPCPool( // send it wil lazy connect on true and try to connect only when the call is make
 			rpcclient.PoolFirst,
 			cfg.TlsCfg().ClientKey,
 			cfg.TlsCfg().ClientCerificate, cfg.TlsCfg().CaCertificate,
 			cfg.GeneralCfg().ConnectAttempts, cfg.GeneralCfg().Reconnects,
 			cfg.GeneralCfg().ConnectTimeout, cfg.GeneralCfg().ReplyTimeout,
-			dH.Conns, IntRPC.GetInternalChanel(), false); err != nil {
+			dH.Conns, IntRPC.GetInternalChanel(), true); err != nil {
 			return nil, err
 		}
 		Cache.Set(utils.CacheDispatcherHosts, tntID, dH, nil,
diff --git a/utils/errors.go b/utils/errors.go
index 6c7fee4eb..7b00756be 100644
--- a/utils/errors.go
+++ b/utils/errors.go
@@ -245,8 +245,10 @@ func IsNetworkError(err error) bool {
 		return false
 	}
 	if operr, ok := err.(*net.OpError); ok &&
-		strings.HasSuffix(operr.Err.Error(),
-			syscall.ECONNRESET.Error()) { // connection reset
+		(strings.HasSuffix(operr.Err.Error(),
+			syscall.ECONNRESET.Error()) ||
+			(strings.HasSuffix(operr.Err.Error(),
+				syscall.ECONNREFUSED.Error()))) { // connection reset
 		return true
 	}
 	return err.Error() == rpc.ErrShutdown.Error() ||
@@ -254,7 +256,8 @@ func IsNetworkError(err error) bool {
 		err.Error() == ErrDisconnected.Error() ||
 		err.Error() == ErrReplyTimeout.Error() ||
 		err.Error() == ErrSessionNotFound.Error() ||
-		strings.HasPrefix(err.Error(), "rpc: can't find service")
+		strings.HasPrefix(err.Error(), "rpc: can't find service") ||
+		strings.HasSuffix(err.Error(), "no such host")
 }
 
 func ErrPathNotReachable(path string) error {