Fix watch for events; add test for interface implementation so it won't break again.

pkg/tools/etcd_tools_watch.go

@@ -17,13 +17,16 @@ limitations under the License.
 package tools
 
 import (
+	"strconv"
 	"sync"
 	"time"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/errors"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/runtime"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/util"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/watch"
+
 	"github.com/coreos/go-etcd/etcd"
 	"github.com/golang/glog"
 )
@@ -37,6 +40,21 @@ func Everything(runtime.Object) bool {
 	return true
 }
 
+// ParseWatchResourceVersion takes a resource version argument and converts it to
+// the etcd version we should pass to helper.Watch(). Because resourceVersion is
+// an opaque value, the default watch behavior for non-zero watch is to watch
+// the next value (if you pass "1", you will see updates from "2" onwards).
+func ParseWatchResourceVersion(resourceVersion, kind string) (uint64, error) {
+	if resourceVersion == "" || resourceVersion == "0" {
+		return 0, nil
+	}
+	version, err := strconv.ParseUint(resourceVersion, 10, 64)
+	if err != nil {
+		return 0, errors.NewInvalid(kind, "", errors.ValidationErrorList{errors.NewFieldInvalid("resourceVersion", resourceVersion)})
+	}
+	return version + 1, nil
+}
+
 // 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. resourceVersion may be used to specify what version to begin

pkg/tools/etcd_tools_watch_test.go

@@ -23,6 +23,7 @@ import (
 	"time"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api"
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/errors"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/latest"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/runtime"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/watch"
@@ -601,3 +602,38 @@ func TestWatchPurposefulShutdown(t *testing.T) {
 		t.Errorf("An injected error did not cause a graceful shutdown")
 	}
 }
+
+func TestEtcdParseWatchResourceVersion(t *testing.T) {
+	testCases := []struct {
+		Version       string
+		Kind          string
+		ExpectVersion uint64
+		Err           bool
+	}{
+		{Version: "", ExpectVersion: 0},
+		{Version: "a", Err: true},
+		{Version: " ", Err: true},
+		{Version: "1", ExpectVersion: 2},
+		{Version: "10", ExpectVersion: 11},
+	}
+	for _, testCase := range testCases {
+		version, err := ParseWatchResourceVersion(testCase.Version, testCase.Kind)
+		switch {
+		case testCase.Err:
+			if err == nil {
+				t.Errorf("%s: unexpected non-error", testCase.Version)
+				continue
+			}
+			if !errors.IsInvalid(err) {
+				t.Errorf("%s: unexpected error: %v", testCase.Version, err)
+				continue
+			}
+		case !testCase.Err && err != nil:
+			t.Errorf("%s: unexpected error: %v", testCase.Version, err)
+			continue
+		}
+		if version != testCase.ExpectVersion {
+			t.Errorf("%s: expected version %d but was %d", testCase.Version, testCase.ExpectVersion, version)
+		}
+	}
+}