Split httpWatcher into watch.StreamWatcher and tools.APIEventDecoder.

pkg/tools/decoder.go

@@ -0,0 +1,53 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package tools
+
+import (
+	"encoding/json"
+	"io"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/watch"
+)
+
+// APIEventDecoder implements the watch.Decoder interface for io.ReadClosers that
+// have contents which consist of a series of api.WatchEvent objects encoded via JSON.
+type APIEventDecoder struct {
+	stream  io.ReadCloser
+	decoder *json.Decoder
+}
+
+// NewAPIEventDecoder makes an APIEventDecoder for the given stream.
+func NewAPIEventDecoder(stream io.ReadCloser) *APIEventDecoder {
+	return &APIEventDecoder{
+		stream:  stream,
+		decoder: json.NewDecoder(stream),
+	}
+}
+
+// Decode blocks until it can return the next object in the stream. Returns an error
+// if the stream is closed or an object can't be decoded.
+func (d *APIEventDecoder) Decode() (action watch.EventType, object interface{}, err error) {
+	var got api.WatchEvent
+	err = d.decoder.Decode(&got)
+	return got.Type, got.Object.Object, err
+}
+
+// Close closes the underlying stream.
+func (d *APIEventDecoder) Close() {
+	d.stream.Close()
+}

pkg/tools/decoder_test.go

@@ -0,0 +1,85 @@
+/*
+Copyright 2014 Google Inc. All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package tools
+
+import (
+	"encoding/json"
+	"io"
+	"reflect"
+	"testing"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/watch"
+)
+
+func TestDecoder(t *testing.T) {
+	out, in := io.Pipe()
+	encoder := json.NewEncoder(in)
+	decoder := NewAPIEventDecoder(out)
+
+	expect := &api.Pod{JSONBase: api.JSONBase{ID: "foo"}}
+	go func() {
+		err := encoder.Encode(api.WatchEvent{watch.Added, api.APIObject{expect}})
+		if err != nil {
+			t.Errorf("Unexpected error %v", err)
+		}
+	}()
+
+	action, got, err := decoder.Decode()
+	if err != nil {
+		t.Errorf("Unexpected error %v", err)
+	}
+	if e, a := watch.Added, action; e != a {
+		t.Errorf("Expected %v, got %v", e, a)
+	}
+	if e, a := expect, got; !reflect.DeepEqual(e, a) {
+		t.Errorf("Expected %v, got %v", e, a)
+	}
+
+	done := make(chan struct{})
+
+	go func() {
+		_, _, err := decoder.Decode()
+		if err == nil {
+			t.Errorf("Unexpected nil error")
+		}
+		close(done)
+	}()
+
+	decoder.Close()
+
+	<-done
+}
+
+func TestDecoder_SourceClose(t *testing.T) {
+	out, in := io.Pipe()
+	decoder := NewAPIEventDecoder(out)
+
+	done := make(chan struct{})
+
+	go func() {
+		_, _, err := decoder.Decode()
+		if err == nil {
+			t.Errorf("Unexpected nil error")
+		}
+		close(done)
+	}()
+
+	in.Close()
+
+	<-done
+}