Log error if scheme is unsupported

(cherry picked from commit df78133bf3)

plugins/outputs/influxdb/http.go

@@ -159,12 +159,18 @@ func NewHTTPClient(config *HTTPConfig) (*httpClient, error) {
 		serializer = influx.NewSerializer()
 	}
 
-	writeURL := makeWriteURL(
+	writeURL, err := makeWriteURL(
 		config.URL,
 		database,
 		config.RetentionPolicy,
 		config.Consistency)
-	queryURL := makeQueryURL(config.URL)
+	if err != nil {
+		return nil, err
+	}
+	queryURL, err := makeQueryURL(config.URL)
+	if err != nil {
+		return nil, err
+	}
 
 	var transport *http.Transport
 	switch config.URL.Scheme {
@@ -399,7 +405,7 @@ func (c *httpClient) addHeaders(req *http.Request) {
 	}
 }
 
-func makeWriteURL(loc *url.URL, db, rp, consistency string) string {
+func makeWriteURL(loc *url.URL, db, rp, consistency string) (string, error) {
 	params := url.Values{}
 	params.Set("db", db)
 
@@ -417,24 +423,26 @@ func makeWriteURL(loc *url.URL, db, rp, consistency string) string {
 		u.Scheme = "http"
 		u.Host = "127.0.0.1"
 		u.Path = "/write"
-	case "http":
-	case "https":
+	case "http", "https":
 		u.Path = path.Join(u.Path, "write")
+	default:
+		return "", fmt.Errorf("unsupported scheme: %q", loc.Scheme)
 	}
 	u.RawQuery = params.Encode()
-	return u.String()
+	return u.String(), nil
 }
 
-func makeQueryURL(loc *url.URL) string {
+func makeQueryURL(loc *url.URL) (string, error) {
 	u := *loc
 	switch u.Scheme {
 	case "unix":
 		u.Scheme = "http"
 		u.Host = "127.0.0.1"
 		u.Path = "/query"
-	case "http":
-	case "https":
+	case "http", "https":
 		u.Path = path.Join(u.Path, "query")
+	default:
+		return "", fmt.Errorf("unsupported scheme: %q", loc.Scheme)
 	}
-	return u.String()
+	return u.String(), nil
 }

plugins/outputs/influxdb/http_test.go

@@ -46,6 +46,17 @@ func TestHTTP_MinimalConfig(t *testing.T) {
 	require.NoError(t, err)
 }
 
+func TestHTTP_UnsupportedScheme(t *testing.T) {
+	config := &influxdb.HTTPConfig{
+		URL: &url.URL{
+			Scheme: "foo",
+			Host:   "localhost",
+		},
+	}
+	_, err := influxdb.NewHTTPClient(config)
+	require.Error(t, err)
+}
+
 func TestHTTP_CreateDatabase(t *testing.T) {
 	ts := httptest.NewServer(http.NotFoundHandler())
 	defer ts.Close()
@@ -576,9 +587,6 @@ func TestHTTP_UnixSocket(t *testing.T) {
 	ts.Start()
 	defer ts.Close()
 
-	x, _ := url.Parse("unix://" + sock)
-	fmt.Println(x)
-
 	successResponse := []byte(`{"results": [{"statement_id": 0}]}`)
 
 	tests := []struct {