[Hybrid] Reconnect to available node

If current connection is lost, find availabe node and reconnect.
Previously, This recovery work is done by user application.
Let's make the users don't care about this work when using MQTT-HYBRID.

*edgesrc and tensor_query_* should be updated after this change.

Signed-off-by: gichan2-jang <gichan2.jang@samsung.com>

src/libnnstreamer-edge/nnstreamer-edge-internal.c

@@ -150,6 +150,11 @@ typedef struct
  nns_edge_conn_s *conn;
 } nns_edge_thread_data_s;
 
+/**
+ * @brief Parse the message received from the MQTT broker and connect to the server directly.
+ */
+static int _mqtt_hybrid_direct_connection (nns_edge_handle_s * eh);
+
 /**
  * @brief Set socket option. nnstreamer-edge handles TCP connection now.
  */
@@ -777,6 +782,10 @@ _nns_edge_message_handler (void *thread_data)
  _nns_edge_remove_connection (eh, client_id);
  nns_edge_event_invoke_callback (eh->event_cb, eh->user_data,
  NNS_EDGE_EVENT_CONNECTION_CLOSED, NULL, 0, NULL);
+ if (NNS_EDGE_CONNECT_TYPE_HYBRID == eh->connect_type) {
+ nns_edge_logd ("Connection lost! Reconnect to available node.");
+ ret = _mqtt_hybrid_direct_connection (eh);
+ }
  }
 
  return NULL;
@@ -1632,6 +1641,12 @@ nns_edge_connect (nns_edge_h edge_h, const char *dest_host, int dest_port)
  return NNS_EDGE_ERROR_CONNECTION_FAILURE;
  }
 
+ if (NNS_EDGE_ERROR_NONE == nns_edge_is_connected (eh)) {
+ nns_edge_logi ("NNStreamer-edge is already connected.");
+ nns_edge_unlock (eh);
+ return NNS_EDGE_ERROR_NONE;
+ }
+
  SAFE_FREE (eh->dest_host);
  eh->dest_host = nns_edge_strdup (dest_host);
  eh->dest_port = dest_port;