config: fix hot-reloading (#1820)

config/config_source.go

@@ -2,7 +2,6 @@ package config
 
 import (
 	"crypto/sha256"
-	"encoding/hex"
 	"io/ioutil"
 	"sync"
 
@@ -124,7 +123,6 @@ type FileWatcherSource struct {
 
 	mu             sync.RWMutex
 	computedConfig *Config
-	version        string
 
 	ChangeDispatcher
 }
@@ -183,10 +181,6 @@ func (src *FileWatcherSource) check(cfg *Config) {
 		}
 	}
 
-	version := hex.EncodeToString(h.Sum(nil))
-	if src.version != version {
-		src.version = version
-
 	// update the computed config
 	src.computedConfig = cfg.Clone()
 	src.computedConfig.Options.Certificates = nil
@@ -194,5 +188,4 @@ func (src *FileWatcherSource) check(cfg *Config) {
 
 	// trigger a change
 	src.Trigger(src.computedConfig)
-	}
 }

config/config_source_test.go

@@ -24,11 +24,13 @@ func TestFileWatcherSource(t *testing.T) {
 		return
 	}
 
-	src := NewFileWatcherSource(NewStaticSource(&Config{
+	ssrc := NewStaticSource(&Config{
 		Options: &Options{
 			CAFile: filepath.Join(tmpdir, "example.txt"),
 		},
-	}))
+	})
+
+	src := NewFileWatcherSource(ssrc)
 	var closeOnce sync.Once
 	ch := make(chan struct{})
 	src.OnConfigChange(func(cfg *Config) {
@@ -47,4 +49,16 @@ func TestFileWatcherSource(t *testing.T) {
 	case <-time.After(time.Second):
 		t.Error("expected OnConfigChange to be fired after modifying a file")
 	}
+
+	ssrc.SetConfig(&Config{
+		Options: &Options{
+			CAFile: filepath.Join(tmpdir, "example.txt"),
+		},
+	})
+
+	select {
+	case <-ch:
+	case <-time.After(time.Second):
+		t.Error("expected OnConfigChange to be fired after triggering a change to the underlying source")
+	}
 }