feat(web): try to reconnect to TDBMS server on failure to get response

web/server/tdbms-client.go

@@ -7,13 +7,29 @@ import (
 
 // TDBMS connection struct
 type TDBMSConnection struct {
-	conn net.Conn
+	domain string
+	addr   string
+	conn   net.Conn
 }
 
 // Connect to TDBMS server
 func (tdbms *TDBMSConnection) Connect(domain, addr string) error {
 	c, err := net.Dial(domain, addr)
-	tdbms.conn = c
+	if err == nil {
+		tdbms.domain = domain
+		tdbms.addr = addr
+		tdbms.conn = c
+	}
+	return err
+}
+
+// Reconnect to TDBMS server
+func (tdbms *TDBMSConnection) Reconnect() error {
+	tdbms.Close()
+	c, err := net.Dial(tdbms.domain, tdbms.addr)
+	if err == nil {
+		tdbms.conn = c
+	}
 	return err
 }
 

web/server/web-server.go

@@ -139,10 +139,21 @@ func HandlerTDBMS(w http.ResponseWriter, r *http.Request) {
 	}
 	response = tdbms.Query(request.TRDB, request.TRC, request.TRB)
 	if response == nil {
-		http.Error(w, "Failed to execute request", http.StatusInternalServerError)
-		defer log.Println("Failed to execute request")
-		return
+		log.Println("Failed to get TDBMS response. Trying to reconnect to TDBMS server...")
+		err = tdbms.Reconnect()
+		if err != nil {
+			http.Error(w, "TDBMS is down", http.StatusServiceUnavailable)
+			defer log.Println("TDBMS is down")
+			return
+		}
+		response = tdbms.Query(request.TRDB, request.TRC, request.TRB)
+		if response == nil {
+			http.Error(w, "Failed to get TDBMS response", http.StatusInternalServerError)
+			defer log.Println("Failed to get TDBMS response")
+			return
+		}
 	}
+	log.Println("Got TDBMS response")
 	if request.TRDB == "$TFM" && (request.TRC == 0b10000 || request.TRC == 0b101000) {
 		var json_response JSON
 		err = json.Unmarshal(response, &json_response)