Refactoring cfg refs and load / save functions (#7749)

* refactoring cfg refs and load / save functions

* improve error output

4 files changed, 119 insertions, 91 deletions

diff --git a/utils/config.go b/utils/config.go
index 2c3a9d291..4b377cce2 100644
--- a/utils/config.go
+++ b/utils/config.go
@@ -70,16 +70,14 @@ func RemoveConfigListener(id string) {
 	delete(cfgListeners, id)
 }
 
-func FindConfigFile(fileName string) string {
-	if _, err := os.Stat("./config/" + fileName); err == nil {
-		fileName, _ = filepath.Abs("./config/" + fileName)
-	} else if _, err := os.Stat("../config/" + fileName); err == nil {
-		fileName, _ = filepath.Abs("../config/" + fileName)
-	} else if _, err := os.Stat(fileName); err == nil {
-		fileName, _ = filepath.Abs(fileName)
+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
+		}
 	}
-
-	return fileName
+	return ""
 }
 
 func FindDir(dir string) (string, bool) {
@@ -197,12 +195,6 @@ func SaveConfig(fileName string, config *model.Config) *model.AppError {
 	return nil
 }
 
-func EnableConfigFromEnviromentVars() {
-	viper.SetEnvPrefix("mm")
-	viper.SetEnvKeyReplacer(strings.NewReplacer(".", "_"))
-	viper.AutomaticEnv()
-}
-
 func InitializeConfigWatch() {
 	cfgMutex.Lock()
 	defer cfgMutex.Unlock()
@@ -230,7 +222,7 @@ func InitializeConfigWatch() {
 							l4g.Info(fmt.Sprintf("Config file watcher detected a change reloading %v", CfgFileName))
 
 							if configReadErr := viper.ReadInConfig(); configReadErr == nil {
-								LoadConfig(CfgFileName)
+								LoadGlobalConfig(CfgFileName)
 							} else {
 								l4g.Error(fmt.Sprintf("Failed to read while watching config file at %v with err=%v", CfgFileName, configReadErr.Error()))
 							}
@@ -274,83 +266,108 @@ func InitAndLoadConfig(filename string) error {
 		return err
 	}
 
-	EnableConfigFromEnviromentVars()
-	LoadConfig(filename)
+	LoadGlobalConfig(filename)
 	InitializeConfigWatch()
 	EnableConfigWatch()
 
 	return nil
 }
 
-// LoadConfig will try to search around for the corresponding config file.
-// It will search /tmp/fileName then attempt ./config/fileName,
-// then ../config/fileName and last it will look at fileName
-func LoadConfig(fileName string) *model.Config {
-	cfgMutex.Lock()
-	defer cfgMutex.Unlock()
-
-	// Cfg should never be null
-	oldConfig := *Cfg
+// ReadConfig reads and parses the given configuration.
+func ReadConfig(r io.Reader, allowEnvironmentOverrides bool) (*model.Config, error) {
+	v := viper.New()
 
-	fileNameWithExtension := filepath.Base(fileName)
-	fileExtension := filepath.Ext(fileNameWithExtension)
-	fileDir := filepath.Dir(fileName)
+	if allowEnvironmentOverrides {
+		v.SetEnvPrefix("mm")
+		v.SetEnvKeyReplacer(strings.NewReplacer(".", "_"))
+		v.AutomaticEnv()
+	}
 
-	if len(fileNameWithExtension) > 0 {
-		fileNameOnly := fileNameWithExtension[:len(fileNameWithExtension)-len(fileExtension)]
-		viper.SetConfigName(fileNameOnly)
-	} else {
-		viper.SetConfigName("config")
+	v.SetConfigType("json")
+	if err := v.ReadConfig(r); err != nil {
+		return nil, err
 	}
 
-	if len(fileDir) > 0 {
-		viper.AddConfigPath(fileDir)
+	var config model.Config
+	unmarshalErr := v.Unmarshal(&config)
+	if unmarshalErr == nil {
+		// https://github.com/spf13/viper/issues/324
+		// https://github.com/spf13/viper/issues/348
+		config.PluginSettings = model.PluginSettings{}
+		unmarshalErr = v.UnmarshalKey("pluginsettings", &config.PluginSettings)
 	}
+	return &config, unmarshalErr
+}
 
-	viper.SetConfigType("json")
-	viper.AddConfigPath("./config")
-	viper.AddConfigPath("../config")
-	viper.AddConfigPath("../../config")
-	viper.AddConfigPath(".")
+// ReadConfigFile reads and parses the configuration at the given file path.
+func ReadConfigFile(path string, allowEnvironmentOverrides bool) (*model.Config, error) {
+	f, err := os.Open(path)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+	return ReadConfig(f, allowEnvironmentOverrides)
+}
 
-	configReadErr := viper.ReadInConfig()
-	if configReadErr != nil {
-		if _, ok := configReadErr.(viper.ConfigFileNotFoundError); ok {
-			// In case of a file-not-found error, try to copy default.json if it's present.
-			defaultPath := FindConfigFile("default.json")
-			if src, err := os.Open(defaultPath); err == nil {
-				if dest, err := os.OpenFile(filepath.Join(filepath.Dir(defaultPath), "config.json"), os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600); err == nil {
-					if _, err := io.Copy(dest, src); err == nil {
-						configReadErr = viper.ReadInConfig()
-					}
-					dest.Close()
-				}
-				src.Close()
-			}
+// 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.
+func EnsureConfigFile(fileName string) (string, error) {
+	if configFile := FindConfigFile(fileName); configFile != "" {
+		return configFile, nil
+	}
+	if defaultPath := FindConfigFile("default.json"); defaultPath != "" {
+		destPath := filepath.Join(filepath.Dir(defaultPath), fileName)
+		src, err := os.Open(defaultPath)
+		if err != nil {
+			return "", err
+		}
+		defer src.Close()
+		dest, err := os.OpenFile(destPath, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0600)
+		if err != nil {
+			return "", err
+		}
+		defer dest.Close()
+		if _, err := io.Copy(dest, src); err == nil {
+			return destPath, nil
 		}
 	}
+	return "", fmt.Errorf("no config file found")
+}
 
-	if configReadErr != nil {
-		errMsg := T("utils.config.load_config.opening.panic", map[string]interface{}{"Filename": fileName, "Error": configReadErr.Error()})
-		fmt.Fprintln(os.Stderr, errMsg)
-		os.Exit(1)
-	}
+// LoadGlobalConfig will try to search around for the corresponding config file.  It will search
+// /tmp/fileName then attempt ./config/fileName, then ../config/fileName and last it will look at
+// fileName
+//
+// XXX: This is deprecated.
+func LoadGlobalConfig(fileName string) *model.Config {
+	cfgMutex.Lock()
+	defer cfgMutex.Unlock()
 
-	var config model.Config
-	unmarshalErr := viper.Unmarshal(&config)
-	if unmarshalErr == nil {
-		// https://github.com/spf13/viper/issues/324
-		// https://github.com/spf13/viper/issues/348
-		config.PluginSettings = model.PluginSettings{}
-		unmarshalErr = viper.UnmarshalKey("pluginsettings", &config.PluginSettings)
+	// Cfg should never be null
+	oldConfig := *Cfg
+
+	var configPath string
+	if fileName != filepath.Base(fileName) {
+		configPath = fileName
+	} else {
+		if path, err := EnsureConfigFile(fileName); err != nil {
+			errMsg := T("utils.config.load_config.opening.panic", map[string]interface{}{"Filename": fileName, "Error": err.Error()})
+			fmt.Fprintln(os.Stderr, errMsg)
+			os.Exit(1)
+		} else {
+			configPath = path
+		}
 	}
-	if unmarshalErr != nil {
-		errMsg := T("utils.config.load_config.decoding.panic", map[string]interface{}{"Filename": fileName, "Error": unmarshalErr.Error()})
+
+	config, err := ReadConfigFile(configPath, true)
+	if err != nil {
+		errMsg := T("utils.config.load_config.decoding.panic", map[string]interface{}{"Filename": fileName, "Error": err.Error()})
 		fmt.Fprintln(os.Stderr, errMsg)
 		os.Exit(1)
 	}
 
-	CfgFileName = viper.ConfigFileUsed()
+	CfgFileName = configPath
 
 	needSave := len(config.SqlSettings.AtRestEncryptKey) == 0 || len(*config.FileSettings.PublicLinkSalt) == 0 ||
 		len(config.EmailSettings.InviteSalt) == 0
@@ -363,16 +380,16 @@ func LoadConfig(fileName string) *model.Config {
 
 	if needSave {
 		cfgMutex.Unlock()
-		if err := SaveConfig(CfgFileName, &config); err != nil {
+		if err := SaveConfig(CfgFileName, config); err != nil {
 			err.Translate(T)
 			l4g.Warn(err.Error())
 		}
 		cfgMutex.Lock()
 	}
 
-	if err := ValidateLocales(&config); err != nil {
+	if err := ValidateLocales(config); err != nil {
 		cfgMutex.Unlock()
-		if err := SaveConfig(CfgFileName, &config); err != nil {
+		if err := SaveConfig(CfgFileName, config); err != nil {
 			err.Translate(T)
 			l4g.Warn(err.Error())
 		}
@@ -388,7 +405,7 @@ func LoadConfig(fileName string) *model.Config {
 		}
 	}
 
-	Cfg = &config
+	Cfg = config
 	CfgHash = fmt.Sprintf("%x", md5.Sum([]byte(Cfg.ToJson())))
 	ClientCfg = getClientConfig(Cfg)
 	clientCfgJson, _ := json.Marshal(ClientCfg)
@@ -398,10 +415,10 @@ func LoadConfig(fileName string) *model.Config {
 	SetSiteURL(*Cfg.ServiceSettings.SiteURL)
 
 	for _, listener := range cfgListeners {
-		listener(&oldConfig, &config)
+		listener(&oldConfig, config)
 	}
 
-	return &config
+	return config
 }
 
 func RegenerateClientConfig() {
diff --git a/utils/config_test.go b/utils/config_test.go
index 527718bbb..92d3c6fd4 100644
--- a/utils/config_test.go
+++ b/utils/config_test.go
@@ -9,25 +9,26 @@ import (
 	"testing"
 	"time"
 
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+
 	"github.com/mattermost/mattermost-server/model"
 )
 
 func TestConfig(t *testing.T) {
 	TranslationsPreInit()
-	LoadConfig("config.json")
+	LoadGlobalConfig("config.json")
 	InitTranslations(Cfg.LocalizationSettings)
 }
 
 func TestConfigFromEnviroVars(t *testing.T) {
-
 	os.Setenv("MM_TEAMSETTINGS_SITENAME", "From Enviroment")
 	os.Setenv("MM_TEAMSETTINGS_CUSTOMBRANDTEXT", "Custom Brand")
 	os.Setenv("MM_SERVICESETTINGS_ENABLECOMMANDS", "false")
 	os.Setenv("MM_SERVICESETTINGS_READTIMEOUT", "400")
 
 	TranslationsPreInit()
-	EnableConfigFromEnviromentVars()
-	LoadConfig("config.json")
+	LoadGlobalConfig("config.json")
 
 	if Cfg.TeamSettings.SiteName != "From Enviroment" {
 		t.Fatal("Couldn't read config from enviroment var")
@@ -56,7 +57,7 @@ func TestConfigFromEnviroVars(t *testing.T) {
 	*Cfg.ServiceSettings.ReadTimeout = 300
 	SaveConfig(CfgFileName, Cfg)
 
-	LoadConfig("config.json")
+	LoadGlobalConfig("config.json")
 
 	if Cfg.TeamSettings.SiteName != "Mattermost" {
 		t.Fatal("should have been reset")
@@ -65,7 +66,7 @@ func TestConfigFromEnviroVars(t *testing.T) {
 
 func TestRedirectStdLog(t *testing.T) {
 	TranslationsPreInit()
-	LoadConfig("config.json")
+	LoadGlobalConfig("config.json")
 	InitTranslations(Cfg.LocalizationSettings)
 
 	log := NewRedirectStdLog("test", false)
@@ -110,8 +111,7 @@ func TestAddRemoveConfigListener(t *testing.T) {
 
 func TestConfigListener(t *testing.T) {
 	TranslationsPreInit()
-	EnableConfigFromEnviromentVars()
-	LoadConfig("config.json")
+	LoadGlobalConfig("config.json")
 
 	SiteName := Cfg.TeamSettings.SiteName
 	defer func() {
@@ -148,7 +148,7 @@ func TestConfigListener(t *testing.T) {
 	listener2Id := AddConfigListener(listener2)
 	defer RemoveConfigListener(listener2Id)
 
-	LoadConfig("config.json")
+	LoadGlobalConfig("config.json")
 
 	if !listenerCalled {
 		t.Fatal("listener should've been called")
@@ -159,7 +159,7 @@ func TestConfigListener(t *testing.T) {
 
 func TestValidateLocales(t *testing.T) {
 	TranslationsPreInit()
-	LoadConfig("config.json")
+	LoadGlobalConfig("config.json")
 
 	defaultServerLocale := *Cfg.LocalizationSettings.DefaultServerLocale
 	defaultClientLocale := *Cfg.LocalizationSettings.DefaultClientLocale
@@ -278,10 +278,21 @@ func TestValidateLocales(t *testing.T) {
 
 func TestGetClientConfig(t *testing.T) {
 	TranslationsPreInit()
-	LoadConfig("config.json")
+	LoadGlobalConfig("config.json")
 
 	configMap := getClientConfig(Cfg)
 	if configMap["EmailNotificationContentsType"] != *Cfg.EmailSettings.EmailNotificationContentsType {
 		t.Fatal("EmailSettings.EmailNotificationContentsType not exposed to client config")
 	}
 }
+
+func TestReadConfig(t *testing.T) {
+	config, err := ReadConfig(strings.NewReader(`{
+		"ServiceSettings": {
+			"SiteURL": "http://foo.bar"
+		}
+	}`), false)
+	require.NoError(t, err)
+
+	assert.Equal(t, "http://foo.bar", *config.ServiceSettings.SiteURL)
+}
diff --git a/utils/file_test.go b/utils/file_test.go
index ed2e8683b..5c7162450 100644
--- a/utils/file_test.go
+++ b/utils/file_test.go
@@ -43,7 +43,7 @@ func TestFileMinioTestSuite(t *testing.T) {
 
 func (s *FileTestSuite) SetupTest() {
 	TranslationsPreInit()
-	LoadConfig("config.json")
+	LoadGlobalConfig("config.json")
 	InitTranslations(Cfg.LocalizationSettings)
 
 	// Save state to restore after the test has run.
diff --git a/utils/mail_test.go b/utils/mail_test.go
index 774ecbf5b..1d4643429 100644
--- a/utils/mail_test.go
+++ b/utils/mail_test.go
@@ -9,7 +9,7 @@ import (
 )
 
 func TestMailConnection(t *testing.T) {
-	LoadConfig("config.json")
+	LoadGlobalConfig("config.json")
 
 	if conn, err := connectToSMTPServer(Cfg); err != nil {
 		t.Log(err)
@@ -32,7 +32,7 @@ func TestMailConnection(t *testing.T) {
 }
 
 func TestSendMail(t *testing.T) {
-	LoadConfig("config.json")
+	LoadGlobalConfig("config.json")
 	T = GetUserTranslations("en")
 
 	var emailTo string = "test@example.com"