Fix tcoudp trigger take much of CPU (#143)

* FIx tcoudp trigger take much of CPU

* listen only once if no delimiter

* revert to keep previous code

* Fixed that we need send data first as long as data is not empty

Author: lixingwang

trigger/tcpudp/README.md

@@ -20,7 +20,7 @@ flogo install github.com/project-flogo/contrib/trigger/tcpudp
 | network    | string  | Network type. Supported types: tcp,tcp4,tcp6,udp,udp4,udp6  - ***REQUIRED***
 | host       | string  | Host IP or DNS resolvable name
 | port       | string  | Port to listen on - ***REQUIRED***
-| delimiter  | string  | Delimiter for read and write. If not set, trigger will read data until EOF
+| delimiter  | string  | Delimiter for read and write. If not set, trigger will take line delimiter '\n' as default value
 | timeout    | integer | Read and Write timeout in milliseconds. To disable timeout, set value to 0.
 
 

trigger/tcpudp/trigger.go

@@ -2,7 +2,6 @@ package tcpudp
 
 import (
 	"bufio"
-	"bytes"
 	"context"
 	"errors"
 	"io"
@@ -111,9 +110,7 @@ func (t *Trigger) handleNewConnection(conn net.Conn) {
 
 	//Gather connection list for later cleanup
 	t.connections = append(t.connections, conn)
-
 	for {
-
 		if t.settings.TimeOut > 0 {
 			t.logger.Info("Setting timeout: ", t.settings.TimeOut)
 			conn.SetDeadline(time.Now().Add(time.Duration(t.settings.TimeOut) * time.Millisecond))
@@ -123,9 +120,13 @@ func (t *Trigger) handleNewConnection(conn net.Conn) {
 
 		if t.delimiter != 0 {
 			data, err := bufio.NewReader(conn).ReadBytes(t.delimiter)
+			if len(data) > 0 {
+				output.Data = string(data)
+				t.triggerFlow(conn, output)
+			}
 			if err != nil {
 				errString := err.Error()
-				if !strings.Contains(errString, "use of closed network connection") {
+				if !strings.Contains(errString, "use of closed network connection") && err != io.EOF {
 					t.logger.Error("Error reading data from connection: ", err.Error())
 				} else {
 					t.logger.Info("Connection is closed.")
@@ -134,16 +135,16 @@ func (t *Trigger) handleNewConnection(conn net.Conn) {
 					// Return if not timeout error
 					return
 				}
-
-			} else {
-				output.Data = string(data[:len(data)-1])
 			}
 		} else {
-			var buf bytes.Buffer
-			_, err := io.Copy(&buf, conn)
+			data, err := bufio.NewReader(conn).ReadBytes('\n')
+			if len(data) > 0 {
+				output.Data = string(data)
+				t.triggerFlow(conn, output)
+			}
 			if err != nil {
 				errString := err.Error()
-				if !strings.Contains(errString, "use of closed network connection") {
+				if !strings.Contains(errString, "use of closed network connection") && err != io.EOF {
 					t.logger.Error("Error reading data from connection: ", err.Error())
 				} else {
 					t.logger.Info("Connection is closed.")
@@ -152,38 +153,38 @@ func (t *Trigger) handleNewConnection(conn net.Conn) {
 					// Return if not timeout error
 					return
 				}
-			} else {
-				output.Data = string(buf.Bytes())
 			}
 		}
+	}
+}
 
-		if output.Data != "" {
-			var replyData []string
-			for i := 0; i < len(t.handlers); i++ {
-				results, err := t.handlers[i].Handle(context.Background(), output)
-				if err != nil {
-					t.logger.Error("Error invoking action : ", err.Error())
-					continue
-				}
+func (t *Trigger) triggerFlow(conn net.Conn, output *Output) {
+	if output.Data != "" {
+		var replyData []string
+		for i := 0; i < len(t.handlers); i++ {
+			results, err := t.handlers[i].Handle(context.Background(), output)
+			if err != nil {
+				t.logger.Error("Error invoking action : ", err.Error())
+				continue
+			}
 
-				reply := &Reply{}
-				err = reply.FromMap(results)
-				if err != nil {
-					t.logger.Error("Failed to convert flow output : ", err.Error())
-					continue
-				}
-				if reply.Reply != "" {
-					replyData = append(replyData, reply.Reply)
-				}
+			reply := &Reply{}
+			err = reply.FromMap(results)
+			if err != nil {
+				t.logger.Error("Failed to convert flow output : ", err.Error())
+				continue
 			}
+			if reply.Reply != "" {
+				replyData = append(replyData, reply.Reply)
+			}
+		}
 
-			if len(replyData) > 0 {
-				replyToSend := strings.Join(replyData, string(t.delimiter))
-				// Send a response back to client contacting us.
-				_, err := conn.Write([]byte(replyToSend + "\n"))
-				if err != nil {
-					t.logger.Error("Failed to write to connection : ", err.Error())
-				}
+		if len(replyData) > 0 {
+			replyToSend := strings.Join(replyData, string(t.delimiter))
+			// Send a response back to client contacting us.
+			_, err := conn.Write([]byte(replyToSend + "\n"))
+			if err != nil {
+				t.logger.Error("Failed to write to connection : ", err.Error())
 			}
 		}
 	}