Handle Close errors for errcheck

Check http response body, websocket, and server connection Close return values to satisfy golangci-lint errcheck.

client/main.go

@@ -56,7 +56,11 @@ func getVkCreds(link string) (string, string, string, error) {
 		if err != nil {
 			return nil, err
 		}
-		defer httpResp.Body.Close()
+		defer func() {
+			if closeErr := httpResp.Body.Close(); closeErr != nil {
+				log.Printf("close response body: %s", closeErr)
+			}
+		}()
 
 		body, err := io.ReadAll(httpResp.Body)
 		if err != nil {
@@ -267,7 +271,11 @@ func getYandexCreds(link string) (string, string, string, error) {
 	if err != nil {
 		return "", "", "", err
 	}
-	defer resp.Body.Close()
+	defer func() {
+		if closeErr := resp.Body.Close(); closeErr != nil {
+			log.Printf("close response body: %s", closeErr)
+		}
+	}()
 	if resp.StatusCode != http.StatusOK {
 		body, _ := io.ReadAll(resp.Body)
 		return "", "", "", fmt.Errorf("GetConference: status=%s body=%s", resp.Status, string(body))
@@ -295,7 +303,11 @@ func getYandexCreds(link string) (string, string, string, error) {
 	if err != nil {
 		return "", "", "", fmt.Errorf("ws dial: %w", err)
 	}
-	defer conn.Close()
+	defer func() {
+		if closeErr := conn.Close(); closeErr != nil {
+			log.Printf("close websocket: %s", closeErr)
+		}
+	}()
 
 	req1 := HelloRequest{
 		UID: uuid.New().String(),

server/main.go

@@ -89,7 +89,11 @@ func main() {
 		wg1.Add(1)
 		go func(conn net.Conn) {
 			defer wg1.Done()
-			defer conn.Close() // graceful shutdown
+			defer func() {
+				if closeErr := conn.Close(); closeErr != nil {
+					log.Printf("failed to close incoming connection: %s", closeErr)
+				}
+			}()
 			var err error = nil
 			log.Printf("Connection from %s\n", conn.RemoteAddr())
 			// `conn` is of type `net.Conn` but may be casted to `dtls.Conn`