Add leases manager interface

Add leases manager to the leases package and use the
interface on the client and service.

Signed-off-by: Derek McGowan <derek@mcgstyle.net>

leases/proxy/manager.go

@@ -0,0 +1,84 @@
+/*
+   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 proxy
+
+import (
+	"context"
+
+	leasesapi "github.com/containerd/containerd/api/services/leases/v1"
+	"github.com/containerd/containerd/leases"
+)
+
+type proxyManager struct {
+	client leasesapi.LeasesClient
+}
+
+// NewLeaseManager returns a lease manager which communicates
+// through a grpc lease service.
+func NewLeaseManager(client leasesapi.LeasesClient) leases.Manager {
+	return &proxyManager{
+		client: client,
+	}
+}
+
+func (pm *proxyManager) Create(ctx context.Context, opts ...leases.Opt) (leases.Lease, error) {
+	l := leases.Lease{}
+	for _, opt := range opts {
+		if err := opt(&l); err != nil {
+			return leases.Lease{}, err
+		}
+	}
+	resp, err := pm.client.Create(ctx, &leasesapi.CreateRequest{
+		ID:     l.ID,
+		Labels: l.Labels,
+	})
+	if err != nil {
+		return leases.Lease{}, err
+	}
+
+	return leases.Lease{
+		ID:        resp.Lease.ID,
+		CreatedAt: resp.Lease.CreatedAt,
+		Labels:    resp.Lease.Labels,
+	}, nil
+}
+
+func (pm *proxyManager) Delete(ctx context.Context, l leases.Lease) error {
+	_, err := pm.client.Delete(ctx, &leasesapi.DeleteRequest{
+		ID: l.ID,
+	})
+	return err
+}
+
+func (pm *proxyManager) List(ctx context.Context, filters ...string) ([]leases.Lease, error) {
+	resp, err := pm.client.List(ctx, &leasesapi.ListRequest{
+		Filters: filters,
+	})
+	if err != nil {
+		return nil, err
+	}
+	l := make([]leases.Lease, len(resp.Leases))
+	for i := range resp.Leases {
+		l[i] = leases.Lease{
+			ID:        resp.Leases[i].ID,
+			CreatedAt: resp.Leases[i].CreatedAt,
+			Labels:    resp.Leases[i].Labels,
+		}
+	}
+
+	return l, nil
+}