Add some sort of auto retry/management for client

client/client.go

@@ -5,41 +5,106 @@ import (
 	"log"
 	"net"
 	"smpptester/pdu"
+	"time"
 )
 
+const RETRY_TIMEOUT = 1 * time.Second
+
 type SMPPClient struct {
-	Id   int
-	conn net.Conn
-	port string
-	log  log.Logger
+	Id        int
+	Connected bool
+	enabled   bool
+	running   bool
+	conn      net.Conn
+	port      string
+	log       log.Logger
+	dcErr     chan (error)
 }
 
 func NewSMPPClient(port string, id int) *SMPPClient {
 	client := &SMPPClient{
-		Id:   id,
-		port: port,
-		log:  log.Logger{},
+		Id:    id,
+		port:  port,
+		log:   log.Logger{},
+		dcErr: make(chan error, 128),
 	}
 	client.log = *log.New(log.Writer(), "", log.LstdFlags)
 	client.log.SetPrefix(fmt.Sprintf("SMPP client %d: ", client.Id))
 	return client
 }
 
-func (c *SMPPClient) Connect() error {
+func (c *SMPPClient) Enable() {
+	if c.enabled {
+		c.log.Printf("SMPP client %d is already enabled", c.Id)
+		return
+	}
+	c.enabled = true
+	c.start()
+	c.log.Printf("SMPP client %d enabled", c.Id)
+}
+func (c *SMPPClient) Disable() {
+	if !c.enabled {
+		c.log.Printf("SMPP client %d is already disabled", c.Id)
+		return
+	}
+	c.enabled = false
+	c.dcErr <- fmt.Errorf("client is disabled")
+	if c.conn != nil {
+		c.conn.Close()
+	}
+	c.log.Printf("SMPP client %d disabled", c.Id)
+}
+
+func (c *SMPPClient) start() {
+	if c.running {
+		c.log.Printf("SMPP client %d is already running", c.Id)
+		return
+	}
+	go func() {
+		c.running = true
+		defer func() {
+			c.running = false
+		}()
+
+		c.log.Printf("SMPP client %d started", c.Id)
+		for {
+			if c.enabled && !c.Connected {
+				c.log.Printf("Trying to connect to %s", c.port)
+				err := c.connect()
+				if err != nil {
+					c.dcErr <- err
+				}
+			}
+			err := <-c.dcErr
+			c.Connected = false
+			if c.enabled {
+				c.log.Printf("Disconnected: '%v' trying again in %d second(s)", err, int(RETRY_TIMEOUT.Seconds()))
+				time.Sleep(RETRY_TIMEOUT)
+			} else {
+				c.log.Printf("Disconnected: '%v' & client is disabled, quitting", err)
+				break
+			}
+		}
+	}()
+}
+
+func (c *SMPPClient) connect() error {
+	if !c.enabled {
+		return fmt.Errorf("client is not enabled")
+	}
+	if c.Connected {
+		return fmt.Errorf("client is already connected")
+	}
 	conn, err := net.Dial("tcp", c.port)
 	if err != nil {
 		return fmt.Errorf("failed to connect to SMPP server: %w", err)
 	}
 	c.log.Printf("SMPP client %d connected to %s", c.Id, c.port)
+	c.Connected = true
 	c.conn = conn
 	return nil
 }
 
-func (c *SMPPClient) Close() {
-	c.conn.Close()
-	c.log.Printf("SMPP client %d closed connection", c.Id)
-}
-
 func (c *SMPPClient) Send(pdata pdu.PDU) error {
 	if c.conn == nil {
 		return fmt.Errorf("connection is not established")
@@ -54,9 +119,10 @@ func (c *SMPPClient) Send(pdata pdu.PDU) error {
 
 	_, err = c.conn.Write(buf.Bytes())
 	if err != nil {
+		c.dcErr <- err
 		return fmt.Errorf("failed to send PDU: %w", err)
 	}
 
 	c.log.Printf("SMPP client %d sent PDU: %+v", c.Id, pdata)
 	return nil
-}
+}