rc: add ability for options blocks to register reload functions

fs/rc/config_test.go

@@ -1,8 +1,10 @@
 package rc
 
 import (
+	"fmt"
 	"testing"
 
+	"github.com/pkg/errors"
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 )
@@ -24,9 +26,21 @@ func TestAddOption(t *testing.T) {
 	assert.Equal(t, len(optionBlock), 0)
 	AddOption("potato", &testOptions)
 	assert.Equal(t, len(optionBlock), 1)
+	assert.Equal(t, len(optionReload), 0)
 	assert.Equal(t, &testOptions, optionBlock["potato"])
 }
 
+func TestAddOptionReload(t *testing.T) {
+	defer clearOptionBlock()
+	assert.Equal(t, len(optionBlock), 0)
+	reload := func() error { return nil }
+	AddOptionReload("potato", &testOptions, reload)
+	assert.Equal(t, len(optionBlock), 1)
+	assert.Equal(t, len(optionReload), 1)
+	assert.Equal(t, &testOptions, optionBlock["potato"])
+	assert.Equal(t, fmt.Sprintf("%p", reload), fmt.Sprintf("%p", optionReload["potato"]))
+}
+
 func TestOptionsBlocks(t *testing.T) {
 	defer clearOptionBlock()
 	AddOption("potato", &testOptions)
@@ -53,7 +67,14 @@ func TestOptionsGet(t *testing.T) {
 
 func TestOptionsSet(t *testing.T) {
 	defer clearOptionBlock()
-	AddOption("potato", &testOptions)
+	var reloaded int
+	AddOptionReload("potato", &testOptions, func() error {
+		if reloaded > 0 {
+			return errors.New("error while reloading")
+		}
+		reloaded++
+		return nil
+	})
 	call := Calls.Get("options/set")
 	require.NotNil(t, call)
 
@@ -67,6 +88,12 @@ func TestOptionsSet(t *testing.T) {
 	require.Nil(t, out)
 	assert.Equal(t, 50, testOptions.Int)
 	assert.Equal(t, "hello", testOptions.String)
+	assert.Equal(t, 1, reloaded)
+
+	// error from reload
+	_, err = call.Fn(in)
+	require.Error(t, err)
+	assert.Contains(t, err.Error(), "error while reloading")
 
 	// unknown option block
 	in = Params{
@@ -85,4 +112,5 @@ func TestOptionsSet(t *testing.T) {
 	_, err = call.Fn(in)
 	require.Error(t, err)
 	assert.Contains(t, err.Error(), "failed to write options")
+
 }