support env variables to overwrite toml file

weed/util/config.go

@@ -1,8 +1,11 @@
 package util
 
 import (
-	"github.com/chrislusf/seaweedfs/weed/glog"
+	"strings"
+
 	"github.com/spf13/viper"
+
+	"github.com/chrislusf/seaweedfs/weed/glog"
 )
 
 type Configuration interface {
@@ -37,3 +40,11 @@ func LoadConfiguration(configFileName string, required bool) (loaded bool) {
 
 	return true
 }
+
+func GetViper() *viper.Viper {
+	v := viper.GetViper()
+	v.AutomaticEnv()
+	v.SetEnvPrefix("weed")
+	v.SetEnvKeyReplacer(strings.NewReplacer(".", "_"))
+	return v
+}

weed/util/config_test.go

@@ -0,0 +1,24 @@
+package util
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestAllKeysWithEnv(t *testing.T) {
+
+	v := GetViper()
+	v.BindEnv("id")
+	v.BindEnv("foo", "foo")
+
+	// bind and define environment variables (including a nested one)
+	os.Setenv("WEED_ID", "13")
+	os.Setenv("WEED_FOO_BAR", "baz")
+
+	sub := v.Sub("foo")
+
+	assert.Equal(t, "13", v.GetString("id"))
+	assert.Equal(t, "baz", sub.GetString("bar"))
+}