Fix provision tool connect error handling (#879)

Signed-off-by: Dušan Borovčanin <dusan.borovcanin@mainflux.com>

tools/mqtt-bench/client.go

@@ -88,7 +88,7 @@ func (c *Client) publish(r chan *runResults) {
 
 	for i := 0; i < c.MsgCount; i++ {
 		wg.Add(1)
-		go func(mut *sync.Mutex, wg *sync.WaitGroup, t *[]*float64, i int, m message) {
+		go func(mut *sync.Mutex, wg *sync.WaitGroup, i int, m message) {
 			defer wg.Done()
 			m.Sent = time.Now()
 
@@ -110,7 +110,7 @@ func (c *Client) publish(r chan *runResults) {
 			if !c.Quiet && i > 0 && i%100 == 0 {
 				log.Printf("Client %v published %v messages and keeps publishing...\n", c.ID, i)
 			}
-		}(&mu, &wg, &times, i, m)
+		}(&mu, &wg, i, m)
 	}
 	wg.Wait()
 

tools/provision/provision.go

@@ -140,7 +140,7 @@ func Provision(conf Config) {
 
 		cid, err := s.CreateChannel(sdk.Channel{Name: fmt.Sprintf("%s-channel-%d", conf.Prefix, i)}, token)
 		if err != nil {
-			log.Fatalf(err.Error())
+			log.Fatalf("Failed to create the channel: %s", err.Error())
 		}
 
 		channels[i] = &cid
@@ -215,13 +215,18 @@ func Provision(conf Config) {
 	fmt.Printf("# List of channels that things can publish to\n" +
 		"# each channel is connected to each thing from things list\n")
 	for i := 0; i < conf.Num; i++ {
-		for j := 0; j < conf.Num; j++ {
+		// Creating a new routine for each connect
+		// might be heavy on the network.
+		go func(wg *sync.WaitGroup, i int) {
 			wg.Add(1)
-			go func(wg *sync.WaitGroup, i, j int) {
-				defer wg.Done()
-				s.ConnectThing(things[j].ID, *channels[i], token)
-			}(&wg, i, j)
-		}
+			defer wg.Done()
+
+			for j := 0; j < conf.Num; j++ {
+				if err := s.ConnectThing(things[j].ID, *channels[i], token); err != nil {
+					log.Fatalf("Failed to connect thing %s to channel %s: %s", things[j].ID, *channels[i], err)
+				}
+			}
+		}(&wg, i)
 		fmt.Printf("[[channels]]\nchannel_id = \"%s\"\n\n", *channels[i])
 	}
 	wg.Wait()