fix config cli option (#7850)

utils/config.go

@@ -70,11 +70,20 @@ func RemoveConfigListener(id string) {
 	delete(cfgListeners, id)
 }
 
+// FindConfigFile attempts to find an existing configuration file. fileName can be an absolute or
+// relative path or name such as "/opt/mattermost/config.json" or simply "config.json". An empty
+// string is returned if no configuration is found.
 func FindConfigFile(fileName string) (path string) {
-	for _, dir := range []string{"./config", "../config", "../../config", "."} {
-		path, _ := filepath.Abs(filepath.Join(dir, fileName))
-		if _, err := os.Stat(path); err == nil {
-			return path
+	if filepath.IsAbs(fileName) {
+		if _, err := os.Stat(fileName); err == nil {
+			return fileName
+		}
+	} else {
+		for _, dir := range []string{"./config", "../config", "../../config", "."} {
+			path, _ := filepath.Abs(filepath.Join(dir, fileName))
+			if _, err := os.Stat(path); err == nil {
+				return path
+			}
 		}
 	}
 	return ""
@@ -310,8 +319,8 @@ func ReadConfigFile(path string, allowEnvironmentOverrides bool) (*model.Config,
 }
 
 // EnsureConfigFile will attempt to locate a config file with the given name. If it does not exist,
-// it will attempt to locate a default config file, and copy it. In either case, the config file
-// path is returned.
+// it will attempt to locate a default config file, and copy it to a file named fileName in the same
+// directory. In either case, the config file path is returned.
 func EnsureConfigFile(fileName string) (string, error) {
 	if configFile := FindConfigFile(fileName); configFile != "" {
 		return configFile, nil

utils/config_test.go

@@ -4,7 +4,9 @@
 package utils
 
 import (
+	"io/ioutil"
 	"os"
+	"path/filepath"
 	"strings"
 	"testing"
 	"time"
@@ -21,6 +23,23 @@ func TestConfig(t *testing.T) {
 	InitTranslations(Cfg.LocalizationSettings)
 }
 
+func TestFindConfigFile(t *testing.T) {
+	dir, err := ioutil.TempDir("", "")
+	require.NoError(t, err)
+	defer os.RemoveAll(dir)
+
+	path := filepath.Join(dir, "config.json")
+	require.NoError(t, ioutil.WriteFile(path, []byte("{}"), 0600))
+
+	assert.Equal(t, path, FindConfigFile(path))
+
+	prevDir, err := os.Getwd()
+	require.NoError(t, err)
+	defer os.Chdir(prevDir)
+	os.Chdir(dir)
+	assert.Equal(t, path, FindConfigFile(path))
+}
+
 func TestConfigFromEnviroVars(t *testing.T) {
 	os.Setenv("MM_TEAMSETTINGS_SITENAME", "From Enviroment")
 	os.Setenv("MM_TEAMSETTINGS_CUSTOMBRANDTEXT", "Custom Brand")