Merge fb72938b55 into 15738813a0

viper.go

@@ -164,6 +164,7 @@ type Viper struct {
 	// Name of file to look for inside the path
 	configName      string
 	configFile      string
+	configFileChain []string
 	configType      string
 	envPrefix       string
 
@@ -312,6 +313,15 @@ func (v *Viper) SetConfigFile(in string) {
 	}
 }
 
+// SetConfigFileChain explicitly defines slice of the path, name and extension of the config files
+// Viper will use these and not check any of the config paths
+func SetConfigChain(in []string) { v.SetConfigFileChain(in) }
+func (v *Viper) SetConfigFileChain(in []string) {
+	if len(in) > 0 {
+		v.configFileChain = in
+	}
+}
+
 // SetEnvPrefix defines a prefix that ENVIRONMENT variables will use.
 // E.g. if your prefix is "spf", the env registry will look for env
 // variables that start with "SPF_".
@@ -1184,8 +1194,34 @@ func (v *Viper) MergeInConfig() error {
 	return v.MergeConfig(bytes.NewReader(file))
 }
 
-// ReadConfig will read a configuration file, setting existing keys to nil if the
+// MergeConfigFileChain repeatedly merge with configFileChain
-// key does not exist in the file.
+func MergeConfigFileChain() error { return v.MergeConfigFileChain() }
+func (v *Viper) MergeConfigFileChain() error {
+	jww.INFO.Println("Attempting to chain merge with configFileChain")
+
+	configFileChain, err := v.getConfigFileChain()
+	if err != nil {
+		return err
+	}
+
+	for i, filename := range configFileChain {
+		if i == 0 {
+			v.SetConfigFile(filename)
+			err := v.ReadInConfig()
+			if err != nil {
+				return err
+			}
+		} else {
+			v.SetConfigFile(filename)
+			err := v.MergeInConfig()
+			if err != nil {
+				return err
+			}
+		}
+	}
+	return nil
+}
+
 func ReadConfig(in io.Reader) error { return v.ReadConfig(in) }
 func (v *Viper) ReadConfig(in io.Reader) error {
 	v.config = make(map[string]interface{})
@@ -1736,6 +1772,22 @@ func (v *Viper) getConfigFile() (string, error) {
 	return v.configFile, nil
 }
 
+func (v *Viper) getConfigFileChain() ([]string, error) {
+	// if explicitly set, then use it
+	// else search config file and return as slice
+	if len(v.configFileChain) > 0 {
+		return v.configFileChain, nil
+	}
+
+	cf, err := v.findConfigFile()
+	if err != nil {
+		return nil, err
+	}
+
+	v.configFileChain = []string{cf}
+	return v.getConfigFileChain()
+}
+
 func (v *Viper) searchInPath(in string) (filename string) {
 	jww.DEBUG.Println("Searching for config in ", in)
 	for _, ext := range SupportedExts {

viper_test.go

@@ -1412,3 +1412,104 @@ func BenchmarkGetBoolFromMap(b *testing.B) {
 		}
 	}
 }
+
+func initConfigsForMerge(t *testing.T) (string, string, func()) {
+
+	var (
+		testDirs   = []string{`a`, `b`, `c`}
+		configName = `config.toml`
+	)
+
+	root, err := ioutil.TempDir("", "")
+
+	cleanup := true
+	defer func() {
+		if cleanup {
+			os.Chdir("..")
+			os.RemoveAll(root)
+		}
+	}()
+
+	assert.Nil(t, err)
+
+	err = os.Chdir(root)
+	assert.Nil(t, err)
+
+	for _, dir := range testDirs {
+		err = os.Mkdir(dir, 0750)
+		assert.Nil(t, err)
+
+		err = ioutil.WriteFile(
+			path.Join(dir, configName),
+			[]byte("key = \"value is "+dir+"\"\n"+dir+" = \""+dir+"\"\n"),
+			0640)
+		assert.Nil(t, err)
+	}
+
+	cleanup = false
+	return root, configName, func() {
+		os.Chdir("..")
+		os.RemoveAll(root)
+	}
+}
+
+func TestMergeConfigChain(t *testing.T) {
+
+	root, config, cleanup := initConfigsForMerge(t)
+	defer cleanup()
+
+	v := New()
+	v.SetDefault(`key`, `default`)
+
+	entries, err := ioutil.ReadDir(root)
+
+	var configfiles []string
+	for i, e := range entries {
+		if e.IsDir() {
+			configfile := path.Join(root, e.Name(), config)
+			configfiles = append(configfiles, configfile)
+
+			v.SetConfigFileChain(configfiles[:i+1])
+			err = v.MergeConfigFileChain()
+			assert.Nil(t, err)
+			assert.Equal(t, `value is `+e.Name(), v.GetString(`key`))
+			assert.Equal(t, `a`, v.GetString(`a`))
+
+			if i == 0 {
+				assert.Equal(t, ``, v.GetString(`b`))
+			} else {
+				assert.Equal(t, `b`, v.GetString(`b`))
+			}
+
+			if i < 2 {
+				assert.Equal(t, ``, v.GetString(`c`))
+			} else {
+				assert.Equal(t, `c`, v.GetString(`c`))
+			}
+		}
+	}
+}
+
+func TestNotSetConfigFileChainMerge(t *testing.T) {
+	// If not set, behavior is identical to ReadInConfig
+
+	root, config, cleanup := initDirs(t)
+	defer cleanup()
+
+	v := New()
+	v.SetConfigName(config)
+	v.SetDefault(`key`, `default`)
+
+	entries, err := ioutil.ReadDir(root)
+	for _, e := range entries {
+		if e.IsDir() {
+			v.AddConfigPath(e.Name())
+		}
+	}
+	assert.Nil(t, err)
+
+	err = v.MergeConfigFileChain()
+	assert.Nil(t, err)
+
+	assert.Equal(t, `value is `+path.Base(v.configPaths[0]), v.GetString(`key`))
+}