Add telegraf url env var (#8987)

config/config.go

@@ -712,6 +712,10 @@ func getDefaultConfigPath() (string, error) {
 		etcfile = programFiles + `\Telegraf\telegraf.conf`
 	}
 	for _, path := range []string{envfile, homefile, etcfile} {
+		if isURL(path) {
+			log.Printf("I! Using config url: %s", path)
+			return path, nil
+		}
 		if _, err := os.Stat(path); err == nil {
 			log.Printf("I! Using config file: %s", path)
 			return path, nil
@@ -723,6 +727,12 @@ func getDefaultConfigPath() (string, error) {
 		" in $TELEGRAF_CONFIG_PATH, %s, or %s", homefile, etcfile)
 }
 
+// isURL checks if string is valid url
+func isURL(str string) bool {
+	u, err := url.Parse(str)
+	return err == nil && u.Scheme != "" && u.Host != ""
+}
+
 // LoadConfig loads the given config file and applies it to c
 func (c *Config) LoadConfig(path string) error {
 	var err error

config/config_test.go

@@ -324,6 +324,22 @@ func TestConfig_URLRetries3FailsThenPasses(t *testing.T) {
 	require.Equal(t, 4, responseCounter)
 }
 
+func TestConfig_getDefaultConfigPathFromEnvURL(t *testing.T) {
+	ts := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusOK)
+	}))
+	defer ts.Close()
+
+	c := NewConfig()
+	err := os.Setenv("TELEGRAF_CONFIG_PATH", ts.URL)
+	require.NoError(t, err)
+	configPath, err := getDefaultConfigPath()
+	require.NoError(t, err)
+	require.Equal(t, ts.URL, configPath)
+	err = c.LoadConfig("")
+	require.NoError(t, err)
+}
+
 func TestConfig_URLLikeFileName(t *testing.T) {
 	c := NewConfig()
 	err := c.LoadConfig("http:##www.example.com.conf")