feat(config): add pipe suport to config:pull

Author: Joshua-Anderson

client/cmd/config.go

@@ -151,21 +151,36 @@ func ConfigUnset(appID string, configVars []string) error {
 
 // ConfigPull pulls an app's config to a file.
 func ConfigPull(appID string, interactive bool, overwrite bool) error {
-	filename := ".env"
+	c, appID, err := load(appID)
 
-	if !overwrite {
-		if _, err := os.Stat(filename); err == nil {
-			return fmt.Errorf("%s already exists, pass -o to overwrite", filename)
-		}
+	if err != nil {
+		return err
 	}
 
-	c, appID, err := load(appID)
+	configVars, err := config.List(c, appID)
 
 	if err != nil {
 		return err
 	}
 
-	configVars, err := config.List(c, appID)
+	stat, err := os.Stdout.Stat()
+
+	if err != nil {
+		return err
+	}
+
+	if (stat.Mode() & os.ModeCharDevice) == 0 {
+		fmt.Print(formatConfig(configVars.Values))
+		return nil
+	}
+
+	filename := ".env"
+
+	if !overwrite {
+		if _, err := os.Stat(filename); err == nil {
+			return fmt.Errorf("%s already exists, pass -o to overwrite", filename)
+		}
+	}
 
 	if interactive {
 		contents, err := ioutil.ReadFile(filename)

client/parser/config.go

@@ -121,7 +121,8 @@ func configPull(argv []string) error {
 	usage := `
 Extract all environment variables from an application for local use.
 
-Your environment will be stored locally in a file named .env. This file can be
+The environmental variables can be piped into a file, 'deis config:pull > file',
+or stored locally in a file named .env. This file can be
 read by foreman to load the local environment for your app.
 
 Usage: deis config:pull [options]