break config.Get and return error with value

config/config.go

@@ -79,7 +79,7 @@ func Sync() error {
 }
 
 // Get a value from the config.
-func Get(path ...string) reader.Value {
+func Get(path ...string) (reader.Value, error) {
 	return DefaultConfig.Get(path...)
 }
 

config/default.go

@@ -193,7 +193,7 @@ func (c *config) Close() error {
 	return nil
 }
 
-func (c *config) Get(path ...string) reader.Value {
+func (c *config) Get(path ...string) (reader.Value, error) {
 	c.RLock()
 	defer c.RUnlock()
 
@@ -203,7 +203,7 @@ func (c *config) Get(path ...string) reader.Value {
 	}
 
 	// no value
-	return newValue()
+	return newValue(), nil
 }
 
 func (c *config) Set(val interface{}, path ...string) {
@@ -263,7 +263,10 @@ func (c *config) Load(sources ...source.Source) error {
 }
 
 func (c *config) Watch(path ...string) (Watcher, error) {
-	value := c.Get(path...)
+	value, err := c.Get(path...)
+	if err != nil {
+		return nil, err
+	}
 
 	w, err := c.opts.Loader.Watch(path...)
 	if err != nil {
@@ -299,8 +302,7 @@ func (w *watcher) Next() (reader.Value, error) {
 			return nil, err
 		}
 
-		w.value = v.Get()
-		return w.value, nil
+		return v.Get()
 	}
 }
 

config/default_test.go

@@ -123,11 +123,15 @@ func TestConfigMerge(t *testing.T) {
 		t.Fatalf("Expected no error but got %v", err)
 	}
 
-	actualHost := conf.Get("amqp", "host").String("backup")
-	if actualHost != "rabbit.testing.com" {
+	actualHost, err := conf.Get("amqp", "host")
+	if err != nil {
+		t.Fatal(err)
+	}
+	host := actualHost.String("backup")
+	if host != "rabbit.testing.com" {
 		t.Fatalf("Expected %v but got %v",
 			"rabbit.testing.com",
-			actualHost)
+			host)
 	}
 }
 
@@ -161,6 +165,10 @@ func TestConfigWatcherDirtyOverrite(t *testing.T) {
 	for i := range ss {
 		k := fmt.Sprintf("key%d", i)
 		v := fmt.Sprintf("val%d", i)
-		equalS(t, conf.Get(k).String(""), v)
+		cc, err := conf.Get(k)
+		if err != nil {
+			t.Fatal(err)
+		}
+		equalS(t, cc.String(""), v)
 	}
 }

config/loader/memory/memory.go

@@ -181,9 +181,11 @@ func (m *memory) update() {
 			continue
 		}
 
+		val, _ := vals.Get(w.path...)
+
 		uv := updateValue{
 			version: m.snap.Version,
-			value:   vals.Get(w.path...),
+			value:   val,
 		}
 
 		select {
@@ -287,7 +289,7 @@ func (m *memory) Get(path ...string) (reader.Value, error) {
 
 	// did sync actually work?
 	if m.vals != nil {
-		return m.vals.Get(path...), nil
+		return m.vals.Get(path...)
 	}
 
 	// assuming vals is nil
@@ -305,7 +307,7 @@ func (m *memory) Get(path ...string) (reader.Value, error) {
 	m.vals = v
 
 	if m.vals != nil {
-		return m.vals.Get(path...), nil
+		return m.vals.Get(path...)
 	}
 
 	// ok we're going hardcore now

config/reader/json/json_test.go

@@ -36,7 +36,9 @@ func TestReader(t *testing.T) {
 	}
 
 	for _, test := range testData {
-		if v := values.Get(test.path...).String(""); v != test.value {
+		if v, err := values.Get(test.path...); err != nil {
+			t.Fatal(err)
+		} else if v.String("") != test.value {
 			t.Fatalf("Expected %s got %s for path %v", test.value, v, test.path)
 		}
 	}

config/reader/json/values.go

@@ -30,8 +30,8 @@ func newValues(ch *source.ChangeSet) (reader.Values, error) {
 	return &jsonValues{ch, sj}, nil
 }
 
-func (j *jsonValues) Get(path ...string) reader.Value {
-	return &jsonValue{j.sj.GetPath(path...)}
+func (j *jsonValues) Get(path ...string) (reader.Value, error) {
+	return &jsonValue{j.sj.GetPath(path...)}, nil
 }
 
 func (j *jsonValues) Del(path ...string) {

config/reader/json/values_test.go

@@ -37,7 +37,11 @@ func TestValues(t *testing.T) {
 			t.Fatal(err)
 		}
 
-		err = values.Get(test.path...).Scan(&test.accepter)
+		v, err := values.Get(test.path...)
+		if err != nil {
+			t.Fatal(err)
+		}
+		err = v.Scan(&test.accepter)
 		if err != nil {
 			t.Fatal(err)
 		}
@@ -74,7 +78,11 @@ func TestStructArray(t *testing.T) {
 			t.Fatal(err)
 		}
 
-		err = values.Get().Scan(&test.accepter)
+		v, err := values.Get()
+		if err != nil {
+			t.Fatal(err)
+		}
+		err = v.Scan(&test.accepter)
 		if err != nil {
 			t.Fatal(err)
 		}

config/reader/reader.go

@@ -17,7 +17,7 @@ type Reader interface {
 // Values is returned by the reader.
 type Values interface {
 	Bytes() []byte
-	Get(path ...string) Value
+	Get(path ...string) (Value, error)
 	Set(val interface{}, path ...string)
 	Del(path ...string)
 	Map() map[string]interface{}

config/source/cli/cli_test.go

@@ -56,7 +56,9 @@ func TestCliSourceDefault(t *testing.T) {
 	)
 
 	config.Load(cliSrc)
-	if fval := config.Get("flag").String("default"); fval != expVal {
+	if val, err := config.Get("flag"); err != nil {
+		t.Fatal(err)
+	} else if fval := val.String("default"); fval != expVal {
 		t.Fatalf("default flag value not loaded %v != %v", fval, expVal)
 	}
 }