From 1b560de7b7aa35596ac371460e52b5e8dfc043c6 Mon Sep 17 00:00:00 2001
From: satotake <doublequotation@gmail.com>
Date: Mon, 3 Apr 2017 02:11:29 +0900
Subject: [PATCH] add ChainMergeConfigFiles

---
 viper.go | 45 ++++++++++++++++++++++++++++++++++++++-------
 1 file changed, 38 insertions(+), 7 deletions(-)

diff --git a/viper.go b/viper.go
index 22a2ed8..96b16f7 100644
--- a/viper.go
+++ b/viper.go
@@ -52,7 +52,7 @@ func init() {
 type remoteConfigFactory interface {
 	Get(rp RemoteProvider) (io.Reader, error)
 	Watch(rp RemoteProvider) (io.Reader, error)
-	WatchChannel(rp RemoteProvider)(<-chan *RemoteResponse, chan bool)
+	WatchChannel(rp RemoteProvider) (<-chan *RemoteResponse, chan bool)
 }
 
 // RemoteConfig is optional, see the remote package
@@ -145,10 +145,11 @@ type Viper struct {
 	remoteProviders []*defaultRemoteProvider
 
 	// Name of file to look for inside the path
-	configName string
-	configFile string
-	configType string
-	envPrefix  string
+	configName  string
+	configFile  string
+	configFiles []string
+	configType  string
+	envPrefix   string
 
 	automaticEnvApplied bool
 	envKeyReplacer      *strings.Replacer
@@ -291,6 +292,15 @@ func (v *Viper) SetConfigFile(in string) {
 	}
 }
 
+// SetConfigFiles 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 SetConfigFiles(in []string) { v.SetConfigFiles(in) }
+func (v *Viper) SetConfigFiles(in []string) {
+	if len(in) > 0 {
+		v.configFiles = 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_"
@@ -1131,8 +1141,29 @@ func (v *Viper) MergeInConfig() error {
 	return v.MergeConfig(bytes.NewReader(file))
 }
 
-// ReadConfig will read a configuration file, setting existing keys to nil if the
-// key does not exist in the file.
+// ChainMergeConfigfiles repeatedly merge with configFiles
+func ChainMergeConfigFiles() error { return v.ChainMergeConfigFiles() }
+func (v *Viper) ChainMergeConfigFiles() error {
+	jww.INFO.Println("Attempting to chain merge with configFiles")
+
+	for i, filename := range v.configFiles {
+		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{})