Add 'ark backup logs' command for retrieval

Signed-off-by: Andy Goldstein <andy.goldstein@gmail.com>

pkg/cmd/cli/backup/backup.go

@@ -32,6 +32,7 @@ func NewCommand(f client.Factory) *cobra.Command {
 	c.AddCommand(
 		NewCreateCommand(f),
 		NewGetCommand(f),
+		NewLogsCommand(f),
 
 		// Will implement describe later
 		// NewDescribeCommand(f),

pkg/cmd/cli/backup/logs.go

@@ -0,0 +1,55 @@
+/*
+Copyright 2017 Heptio Inc.
+
+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 backup
+
+import (
+	"errors"
+	"os"
+	"time"
+
+	"github.com/spf13/cobra"
+
+	"github.com/heptio/ark/pkg/apis/ark/v1"
+	"github.com/heptio/ark/pkg/client"
+	"github.com/heptio/ark/pkg/cmd"
+	"github.com/heptio/ark/pkg/cmd/util/downloadrequest"
+)
+
+func NewLogsCommand(f client.Factory) *cobra.Command {
+	timeout := time.Minute
+
+	c := &cobra.Command{
+		Use:   "logs BACKUP",
+		Short: "Get backup logs",
+		Run: func(c *cobra.Command, args []string) {
+			if len(args) != 1 {
+				err := errors.New("backup name is required")
+				cmd.CheckError(err)
+			}
+
+			arkClient, err := f.Client()
+			cmd.CheckError(err)
+
+			err = downloadrequest.Stream(arkClient.ArkV1(), args[0], v1.DownloadTargetKindBackupLog, os.Stdout, timeout)
+			cmd.CheckError(err)
+		},
+	}
+
+	c.Flags().DurationVar(&timeout, "timeout", timeout, "how long to wait to receive logs")
+
+	return c
+}