Move namespaces to pkg/namespaces

Signed-off-by: Derek McGowan <derek@mcg.dev>

pkg/namespaces/store.go

@@ -0,0 +1,44 @@
+/*
+   Copyright The containerd Authors.
+
+   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 namespaces
+
+import "context"
+
+// Store provides introspection about namespaces.
+//
+// Note that these are slightly different than other objects, which are record
+// oriented. A namespace is really just a name and a set of labels. Objects
+// that belong to a namespace are returned when the namespace is assigned to a
+// given context.
+type Store interface {
+	Create(ctx context.Context, namespace string, labels map[string]string) error
+	Labels(ctx context.Context, namespace string) (map[string]string, error)
+	SetLabel(ctx context.Context, namespace, key, value string) error
+	List(ctx context.Context) ([]string, error)
+
+	// Delete removes the namespace. The namespace must be empty to be deleted.
+	Delete(ctx context.Context, namespace string, opts ...DeleteOpts) error
+}
+
+// DeleteInfo specifies information for the deletion of a namespace
+type DeleteInfo struct {
+	// Name of the namespace
+	Name string
+}
+
+// DeleteOpts allows the caller to set options for namespace deletion
+type DeleteOpts func(context.Context, *DeleteInfo) error