Add more parameters to Watch

* Add labels selector (same as List)
* Add fields selector
 * Plan to let you select pods by Host and/or Status
* Add resourceVersion to let you resume a watch where you left off.

pkg/apiserver/apiserver_test.go

@@ -70,6 +70,11 @@ type SimpleRESTStorage struct {
 	// Set if WatchSingle is called
 	requestedID string
 
+	// Set if WatchAll is called
+	requestedLabelSelector   labels.Selector
+	requestedFieldSelector   labels.Selector
+	requestedResourceVersion uint64
+
 	// If non-nil, called inside the WorkFunc when answering update, delete, create.
 	// obj receives the original input to the update, delete, or create call.
 	injectedFunction func(obj interface{}) (returnObj interface{}, err error)
@@ -95,7 +100,7 @@ func (storage *SimpleRESTStorage) Delete(id string) (<-chan interface{}, error)
 		if storage.injectedFunction != nil {
 			return storage.injectedFunction(id)
 		}
-		return api.Status{Status: api.StatusSuccess}, nil
+		return &api.Status{Status: api.StatusSuccess}, nil
 	}), nil
 }
 
@@ -130,7 +135,10 @@ func (storage *SimpleRESTStorage) Update(obj interface{}) (<-chan interface{}, e
 }
 
 // Implement ResourceWatcher.
-func (storage *SimpleRESTStorage) WatchAll() (watch.Interface, error) {
+func (storage *SimpleRESTStorage) WatchAll(label, field labels.Selector, resourceVersion uint64) (watch.Interface, error) {
+	storage.requestedLabelSelector = label
+	storage.requestedFieldSelector = field
+	storage.requestedResourceVersion = resourceVersion
 	if err := storage.errors["watchAll"]; err != nil {
 		return nil, err
 	}
@@ -139,8 +147,9 @@ func (storage *SimpleRESTStorage) WatchAll() (watch.Interface, error) {
 }
 
 // Implement ResourceWatcher.
-func (storage *SimpleRESTStorage) WatchSingle(id string) (watch.Interface, error) {
+func (storage *SimpleRESTStorage) WatchSingle(id string, resourceVersion uint64) (watch.Interface, error) {
 	storage.requestedID = id
+	storage.requestedResourceVersion = resourceVersion
 	if err := storage.errors["watchSingle"]; err != nil {
 		return nil, err
 	}
@@ -164,17 +173,17 @@ func TestNotFound(t *testing.T) {
 		Path   string
 	}
 	cases := map[string]T{
-		"PATCH method":                 T{"PATCH", "/prefix/version/foo"},
-		"GET long prefix":              T{"GET", "/prefix/"},
-		"GET missing storage":          T{"GET", "/prefix/version/blah"},
-		"GET with extra segment":       T{"GET", "/prefix/version/foo/bar/baz"},
-		"POST with extra segment":      T{"POST", "/prefix/version/foo/bar"},
-		"DELETE without extra segment": T{"DELETE", "/prefix/version/foo"},
-		"DELETE with extra segment":    T{"DELETE", "/prefix/version/foo/bar/baz"},
-		"PUT without extra segment":    T{"PUT", "/prefix/version/foo"},
-		"PUT with extra segment":       T{"PUT", "/prefix/version/foo/bar/baz"},
-		"watch missing storage":        T{"GET", "/prefix/version/watch/"},
-		"watch with bad method":        T{"POST", "/prefix/version/watch/foo/bar"},
+		"PATCH method":                 {"PATCH", "/prefix/version/foo"},
+		"GET long prefix":              {"GET", "/prefix/"},
+		"GET missing storage":          {"GET", "/prefix/version/blah"},
+		"GET with extra segment":       {"GET", "/prefix/version/foo/bar/baz"},
+		"POST with extra segment":      {"POST", "/prefix/version/foo/bar"},
+		"DELETE without extra segment": {"DELETE", "/prefix/version/foo"},
+		"DELETE with extra segment":    {"DELETE", "/prefix/version/foo/bar/baz"},
+		"PUT without extra segment":    {"PUT", "/prefix/version/foo"},
+		"PUT with extra segment":       {"PUT", "/prefix/version/foo/bar/baz"},
+		"watch missing storage":        {"GET", "/prefix/version/watch/"},
+		"watch with bad method":        {"POST", "/prefix/version/watch/foo/bar"},
 	}
 	handler := New(map[string]RESTStorage{
 		"foo": &SimpleRESTStorage{},

pkg/apiserver/interfaces.go

@@ -29,6 +29,7 @@ type RESTStorage interface {
 	New() interface{}
 
 	// List selects resources in the storage which match to the selector.
+	// TODO: add field selector in addition to label selector.
 	List(labels.Selector) (interface{}, error)
 
 	// Get finds a resource in the storage by id and returns it.
@@ -46,7 +47,10 @@ type RESTStorage interface {
 // ResourceWatcher should be implemented by all RESTStorage objects that
 // want to offer the ability to watch for changes through the watch api.
 type ResourceWatcher interface {
-	// TODO: take a query, like List, to filter out unwanted events.
-	WatchAll() (watch.Interface, error)
-	WatchSingle(id string) (watch.Interface, error)
+	// label selects on labels; field selects on the objects fields. Not all fields
+	// are supported; an error will be returned if you try to select for a field that
+	// isn't supported.
+	WatchAll(label, field labels.Selector, resourceVersion uint64) (watch.Interface, error)
+	// TODO: Decide if we need to keep WatchSingle?
+	WatchSingle(id string, resourceVersion uint64) (watch.Interface, error)
 }

pkg/apiserver/watch.go

@@ -19,17 +19,38 @@ package apiserver
 import (
 	"encoding/json"
 	"net/http"
+	"net/url"
+	"strconv"
 
 	"code.google.com/p/go.net/websocket"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/httplog"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/labels"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/watch"
 )
 
 type WatchHandler struct {
 	storage map[string]RESTStorage
 }
 
+func (s *APIServer) getWatchParams(query url.Values) (id string, label, field labels.Selector, resourceVersion uint64) {
+	id = query.Get("id")
+	if s, err := labels.ParseSelector(query.Get("labels")); err != nil {
+		label = labels.Everything()
+	} else {
+		label = s
+	}
+	if s, err := labels.ParseSelector(query.Get("fields")); err != nil {
+		field = labels.Everything()
+	} else {
+		field = s
+	}
+	if rv, err := strconv.ParseUint(query.Get("resourceVersion"), 10, 64); err == nil {
+		resourceVersion = rv
+	}
+	return id, label, field, resourceVersion
+}
+
 // handleWatch processes a watch request
 func (h *WatchHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	parts := splitPath(req.URL.Path)
@@ -43,10 +64,11 @@ func (h *WatchHandler) ServeHTTP(w http.ResponseWriter, req *http.Request) {
 	if watcher, ok := storage.(ResourceWatcher); ok {
 		var watching watch.Interface
 		var err error
-		if id := req.URL.Query().Get("id"); id != "" {
-			watching, err = watcher.WatchSingle(id)
+		id, label, field, resourceVersion := s.getWatchParams(req.URL.Query())
+		if id != "" {
+			watching, err = watcher.WatchSingle(id, resourceVersion)
 		} else {
-			watching, err = watcher.WatchAll()
+			watching, err = watcher.WatchAll(label, field, resourceVersion)
 		}
 		if err != nil {
 			internalError(err, w)

pkg/apiserver/watch_test.go

@@ -148,3 +148,70 @@ func TestWatchHTTP(t *testing.T) {
 		t.Errorf("Unexpected non-error")
 	}
 }
+
+func TestWatchParamParsing(t *testing.T) {
+	simpleStorage := &SimpleRESTStorage{}
+	handler := New(map[string]RESTStorage{
+		"foo": simpleStorage,
+	}, "/prefix/version")
+	server := httptest.NewServer(handler)
+
+	dest, _ := url.Parse(server.URL)
+	dest.Path = "/prefix/version/watch/foo"
+
+	table := []struct {
+		rawQuery        string
+		resourceVersion uint64
+		labelSelector   string
+		fieldSelector   string
+		id              string
+	}{
+		{
+			rawQuery:        "id=myID&resourceVersion=1234",
+			resourceVersion: 1234,
+			labelSelector:   "",
+			fieldSelector:   "",
+			id:              "myID",
+		}, {
+			rawQuery:        "resourceVersion=314159&fields=Host%3D&labels=name%3Dfoo",
+			resourceVersion: 314159,
+			labelSelector:   "name=foo",
+			fieldSelector:   "Host=",
+			id:              "",
+		}, {
+			rawQuery:        "",
+			resourceVersion: 0,
+			labelSelector:   "",
+			fieldSelector:   "",
+			id:              "",
+		},
+	}
+
+	for _, item := range table {
+		simpleStorage.requestedLabelSelector = nil
+		simpleStorage.requestedFieldSelector = nil
+		simpleStorage.requestedResourceVersion = 5 // Prove this is set in all cases
+		simpleStorage.requestedID = ""
+		dest.RawQuery = item.rawQuery
+		resp, err := http.Get(dest.String())
+		if err != nil {
+			t.Errorf("%v: unexpected error: %v", item.rawQuery, err)
+			continue
+		}
+		resp.Body.Close()
+		if e, a := item.id, simpleStorage.requestedID; e != a {
+			t.Errorf("%v: expected %v, got %v", item.rawQuery, e, a)
+		}
+		if e, a := item.resourceVersion, simpleStorage.requestedResourceVersion; e != a {
+			t.Errorf("%v: expected %v, got %v", item.rawQuery, e, a)
+		}
+		if simpleStorage.requestedID == "" {
+			if e, a := item.labelSelector, simpleStorage.requestedLabelSelector.String(); e != a {
+				t.Errorf("%v: expected %v, got %v", item.rawQuery, e, a)
+			}
+			if e, a := item.fieldSelector, simpleStorage.requestedFieldSelector.String(); e != a {
+				t.Errorf("%v: expected %v, got %v", item.rawQuery, e, a)
+			}
+		}
+	}
+}

pkg/registry/controllerstorage.go

@@ -138,12 +138,12 @@ func (storage *ControllerRegistryStorage) waitForController(ctrl api.Replication
 
 // WatchAll returns ReplicationController events via a watch.Interface, implementing
 // apiserver.ResourceWatcher.
-func (storage *ControllerRegistryStorage) WatchAll() (watch.Interface, error) {
-	return storage.registry.WatchControllers()
+func (storage *ControllerRegistryStorage) WatchAll(label, field labels.Selector, resourceVersion uint64) (watch.Interface, error) {
+	return storage.registry.WatchControllers(label, field, resourceVersion)
 }
 
 // WatchSingle returns events for a single ReplicationController via a watch.Interface,
 // implementing apiserver.ResourceWatcher.
-func (storage *ControllerRegistryStorage) WatchSingle(id string) (watch.Interface, error) {
+func (storage *ControllerRegistryStorage) WatchSingle(id string, resourceVersion uint64) (watch.Interface, error) {
 	return nil, errors.New("unimplemented")
 }

pkg/registry/controllerstorage_test.go

@@ -29,6 +29,7 @@ import (
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/watch"
 )
 
+// TODO: Why do we have this AND MemoryRegistry?
 type MockControllerRegistry struct {
 	err         error
 	controllers []api.ReplicationController
@@ -49,10 +50,12 @@ func (registry *MockControllerRegistry) CreateController(controller api.Replicat
 func (registry *MockControllerRegistry) UpdateController(controller api.ReplicationController) error {
 	return registry.err
 }
+
 func (registry *MockControllerRegistry) DeleteController(ID string) error {
 	return registry.err
 }
-func (registry *MockControllerRegistry) WatchControllers() (watch.Interface, error) {
+
+func (registry *MockControllerRegistry) WatchControllers(label, field labels.Selector, resourceVersion uint64) (watch.Interface, error) {
 	return nil, registry.err
 }
 

pkg/registry/etcdregistry.go

@@ -205,9 +205,13 @@ func (registry *EtcdRegistry) ListControllers() ([]api.ReplicationController, er
 }
 
 // WatchControllers begins watching for new, changed, or deleted controllers.
-// TODO: Add id/selector parameters?
-func (registry *EtcdRegistry) WatchControllers() (watch.Interface, error) {
-	return registry.helper.WatchList("/registry/controllers", tools.Everything)
+func (registry *EtcdRegistry) WatchControllers(label, field labels.Selector, resourceVersion uint64) (watch.Interface, error) {
+	if field.String() != "" {
+		return nil, fmt.Errorf("no field selector implemented for controllers")
+	}
+	return registry.helper.WatchList("/registry/controllers", resourceVersion, func(obj interface{}) bool {
+		return label.Matches(labels.Set(obj.(*api.ReplicationController).Labels))
+	})
 }
 
 func makeControllerKey(id string) string {

pkg/registry/interfaces.go

@@ -39,7 +39,7 @@ type PodRegistry interface {
 // ControllerRegistry is an interface for things that know how to store ReplicationControllers.
 type ControllerRegistry interface {
 	ListControllers() ([]api.ReplicationController, error)
-	WatchControllers() (watch.Interface, error)
+	WatchControllers(label, field labels.Selector, resourceVersion uint64) (watch.Interface, error)
 	GetController(controllerID string) (*api.ReplicationController, error)
 	CreateController(controller api.ReplicationController) error
 	UpdateController(controller api.ReplicationController) error

pkg/registry/memory_registry.go

@@ -89,7 +89,7 @@ func (registry *MemoryRegistry) ListControllers() ([]api.ReplicationController,
 	return result, nil
 }
 
-func (registry *MemoryRegistry) WatchControllers() (watch.Interface, error) {
+func (registry *MemoryRegistry) WatchControllers(label, field labels.Selector, resourceVersion uint64) (watch.Interface, error) {
 	return nil, errors.New("unimplemented")
 }
 

pkg/tools/etcd_tools.go

@@ -296,18 +296,19 @@ func Everything(interface{}) bool {
 
 // WatchList begins watching the specified key's items. Items are decoded into
 // API objects, and any items passing 'filter' are sent down the returned
-// watch.Interface.
-func (h *EtcdHelper) WatchList(key string, filter FilterFunc) (watch.Interface, error) {
+// watch.Interface. resourceVersion may be used to specify what version to begin
+// watching (e.g., for reconnecting without missing any updateds).
+func (h *EtcdHelper) WatchList(key string, resourceVersion uint64, filter FilterFunc) (watch.Interface, error) {
 	w := newEtcdWatcher(true, filter, h.Codec)
-	go w.etcdWatch(h.Client, key)
+	go w.etcdWatch(h.Client, key, resourceVersion)
 	return w, nil
 }
 
 // Watch begins watching the specified key. Events are decoded into
 // API objects and sent down the returned watch.Interface.
-func (h *EtcdHelper) Watch(key string) (watch.Interface, error) {
+func (h *EtcdHelper) Watch(key string, resourceVersion uint64) (watch.Interface, error) {
 	w := newEtcdWatcher(false, nil, h.Codec)
-	go w.etcdWatch(h.Client, key)
+	go w.etcdWatch(h.Client, key, resourceVersion)
 	return w, nil
 }
 
@@ -350,10 +351,10 @@ func newEtcdWatcher(list bool, filter FilterFunc, encoding Codec) *etcdWatcher {
 
 // etcdWatch calls etcd's Watch function, and handles any errors. Meant to be called
 // as a goroutine.
-func (w *etcdWatcher) etcdWatch(client EtcdGetSet, key string) {
+func (w *etcdWatcher) etcdWatch(client EtcdGetSet, key string, resourceVersion uint64) {
 	defer util.HandleCrash()
 	defer close(w.etcdCallEnded)
-	_, err := client.Watch(key, 0, w.list, w.etcdIncoming, w.etcdStop)
+	_, err := client.Watch(key, resourceVersion, w.list, w.etcdIncoming, w.etcdStop)
 	if err != etcd.ErrWatchStoppedByUser {
 		glog.Errorf("etcd.Watch stopped unexpectedly: %v (%#v)", err, err)
 	}
@@ -385,18 +386,20 @@ func (w *etcdWatcher) sendResult(res *etcd.Response) {
 	var action watch.EventType
 	var data []byte
 	switch res.Action {
-	case "create", "set":
+	case "create":
 		if res.Node == nil {
 			glog.Errorf("unexpected nil node: %#v", res)
 			return
 		}
 		data = []byte(res.Node.Value)
-		// TODO: Is this conditional correct?
-		if res.EtcdIndex > 0 {
-			action = watch.Modified
-		} else {
-			action = watch.Added
+		action = watch.Added
+	case "set":
+		if res.Node == nil {
+			glog.Errorf("unexpected nil node: %#v", res)
+			return
 		}
+		data = []byte(res.Node.Value)
+		action = watch.Modified
 	case "delete":
 		if res.PrevNode == nil {
 			glog.Errorf("unexpected nil prev node: %#v", res)