Merge pull request #114 from BenTheElder/clusters

add `kind get clusters`

cmd/kind/get/clusters/clusters.go

@@ -0,0 +1,52 @@
+/*
+Copyright 2018 The Kubernetes 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 clusters implements the `clusters` command
+package clusters
+
+import (
+	"fmt"
+
+	"github.com/pkg/errors"
+	"github.com/spf13/cobra"
+
+	"sigs.k8s.io/kind/pkg/cluster"
+)
+
+// NewCommand returns a new cobra.Command for getting the list of clusters
+func NewCommand() *cobra.Command {
+	cmd := &cobra.Command{
+		// TODO(bentheelder): more detailed usage
+		Use:   "clusters",
+		Short: "lists existing kind clusters by their name",
+		Long:  "lists existing kind clusters by their name",
+		RunE: func(cmd *cobra.Command, args []string) error {
+			return runE(cmd, args)
+		},
+	}
+	return cmd
+}
+
+func runE(cmd *cobra.Command, args []string) error {
+	clusters, err := cluster.List()
+	if err != nil {
+		return errors.Wrap(err, "error listing clusters")
+	}
+	for _, cluster := range clusters {
+		fmt.Println(cluster.Name())
+	}
+	return nil
+}

cmd/kind/get/get.go

@@ -20,6 +20,7 @@ package get
 import (
 	"github.com/spf13/cobra"
 
+	"sigs.k8s.io/kind/cmd/kind/get/clusters"
 	"sigs.k8s.io/kind/cmd/kind/get/kubeconfigpath"
 )
 
@@ -28,13 +29,14 @@ func NewCommand() *cobra.Command {
 	cmd := &cobra.Command{
 		// TODO(bentheelder): more detailed usage
 		Use:   "get",
-		Short: "Gets one of [kubeconfig-path]",
-		Long:  "Gets one of [kubeconfig-path]",
+		Short: "Gets one of [clusters, kubeconfig-path]",
+		Long:  "Gets one of [clusters, kubeconfig-path]",
 		RunE: func(cmd *cobra.Command, args []string) error {
 			return cmd.Help()
 		},
 	}
 	// add subcommands
+	cmd.AddCommand(clusters.NewCommand())
 	cmd.AddCommand(kubeconfigpath.NewCommand())
 	return cmd
 }

pkg/cluster/clusters.go

@@ -0,0 +1,36 @@
+/*
+Copyright 2018 The Kubernetes 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 cluster
+
+import (
+	"github.com/pkg/errors"
+
+	"sigs.k8s.io/kind/pkg/cluster/nodes"
+)
+
+// List returns a list of clusters for which node containers exist
+func List() ([]Context, error) {
+	n, err := nodes.ListByCluster()
+	if err != nil {
+		return nil, errors.Wrap(err, "could not list clusters, failed to list nodes")
+	}
+	clusters := []Context{}
+	for name := range n {
+		clusters = append(clusters, *newContextNoValidation(name))
+	}
+	return clusters, nil
+}

pkg/cluster/cluster.go → pkg/cluster/context.go

@@ -53,6 +53,9 @@ var validNameRE = regexp.MustCompile(`^[a-zA-Z0-9_.-]+$`)
 // NewContext returns a new cluster management context
 // if name is "" the default ("1") will be used
 func NewContext(name string) (ctx *Context, err error) {
+	// TODO(bentheelder): move validation out of NewContext and into create type
+	// calls, so that EG delete still works on previously valid, now invalid
+	// names if kind updates
 	if name == "" {
 		name = "1"
 	}
@@ -63,9 +66,17 @@ func NewContext(name string) (ctx *Context, err error) {
 			name, validNameRE.String(),
 		)
 	}
+	return newContextNoValidation(name), nil
+}
+
+// internal helper that does the actual allocation consitently, but does not
+// validate the cluster name
+// we need this so that if we tighten the validation, other internal code
+// can still create contexts to existing clusters by name (see List())
+func newContextNoValidation(name string) *Context {
 	return &Context{
 		name: name,
-	}, nil
+	}
 }
 
 // ClusterLabel returns the docker object label that will be applied

pkg/cluster/nodes/nodes.go

@@ -17,6 +17,9 @@ limitations under the License.
 package nodes
 
 import (
+	"fmt"
+	"strings"
+
 	"github.com/pkg/errors"
 	"sigs.k8s.io/kind/pkg/cluster/consts"
 
@@ -52,8 +55,9 @@ func Delete(nodes ...*Node) error {
 func List(filters ...string) ([]*Node, error) {
 	args := []string{
 		"ps",
-		"-q", // quiet output for parsing
-		"-a", // show stopped nodes
+		"-q",         // quiet output for parsing
+		"-a",         // show stopped nodes
+		"--no-trunc", // don't truncate
 		// filter for nodes with the cluster label
 		"--filter", "label=" + consts.ClusterLabelKey,
 	}
@@ -72,3 +76,33 @@ func List(filters ...string) ([]*Node, error) {
 	}
 	return nodes, nil
 }
+
+// ListByCluster returns a list of nodes by the kind cluster name
+func ListByCluster() (map[string][]Node, error) {
+	args := []string{
+		"ps",
+		"-q",         // quiet output for parsing
+		"-a",         // show stopped nodes
+		"--no-trunc", // don't truncate
+		// filter for nodes with the cluster label
+		"--filter", "label=" + consts.ClusterLabelKey,
+		// format to include friendly name and the cluster name
+		"--format", fmt.Sprintf(`{{.Names}}\t{{.Label "%s"}}`, consts.ClusterLabelKey),
+	}
+	cmd := exec.Command("docker", args...)
+	lines, err := exec.CombinedOutputLines(cmd)
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to list nodes")
+	}
+	nodes := make(map[string][]Node)
+	for _, line := range lines {
+		parts := strings.Split(line, "\t")
+		if len(parts) != 2 {
+			return nil, fmt.Errorf("invalid output when listing nodes: %s", line)
+		}
+		names := strings.Split(parts[0], ",")
+		cluster := parts[1]
+		nodes[cluster] = append(nodes[cluster], *FromID(names[0]))
+	}
+	return nodes, nil
+}