Add dynamic shell completion for unmanaged-cluster

Related to vmware-tanzu/tanzu-framework#701

Signed-off-by: Marc Khouzam <kmarc@vmware.com>

cli/cmd/plugin/unmanaged-cluster/completion/completion.go

@@ -0,0 +1,71 @@
+// Copyright 2022 VMware Tanzu Community Edition contributors. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package completion
+
+import (
+	"fmt"
+
+	"github.com/spf13/cobra"
+
+	"github.com/vmware-tanzu/community-edition/cli/cmd/plugin/unmanaged-cluster/cluster"
+	"github.com/vmware-tanzu/community-edition/cli/cmd/plugin/unmanaged-cluster/cmd"
+	"github.com/vmware-tanzu/community-edition/cli/cmd/plugin/unmanaged-cluster/config"
+	logger "github.com/vmware-tanzu/community-edition/cli/cmd/plugin/unmanaged-cluster/log"
+	"github.com/vmware-tanzu/community-edition/cli/cmd/plugin/unmanaged-cluster/tanzu"
+)
+
+const clusterAnyStatus = ""
+
+func Setup(rootCmd *cobra.Command) {
+	// The below commands accept the names of existing clusters
+	cmd.DeleteCmd.ValidArgsFunction = completeExistingClusterName(clusterAnyStatus)
+	cmd.StartCmd.ValidArgsFunction = completeExistingClusterName(cluster.StatusStopped)
+	cmd.StopCmd.ValidArgsFunction = completeExistingClusterName(cluster.StatusRunning)
+
+	// The below commands should not provide any shell completion choices nor file names
+	cmd.ConfigureCmd.ValidArgsFunction = cobra.NoFileCompletions
+	cmd.CreateCmd.ValidArgsFunction = cobra.NoFileCompletions
+	cmd.ListCmd.ValidArgsFunction = cobra.NoFileCompletions
+}
+
+// completeExistingClusterName returns a completion function that lists all clusters that match
+// the specified clusterStatus.  If clusterStatus is clusterAnyStatus, all clusters will match.
+func completeExistingClusterName(clusterStatus string) func(*cobra.Command, []string, string) ([]string, cobra.ShellCompDirective) {
+	return func(c *cobra.Command, args []string, toComplete string) ([]string, cobra.ShellCompDirective) {
+		if len(args) > 0 {
+			// No more args accepted
+			return nil, cobra.ShellCompDirectiveNoFileComp
+		}
+
+		log := logger.NewLogger(false, 0) // No need for logs
+		tClient := tanzu.New(log)
+
+		// Find clusters and their status
+		clusters, err := tClient.List()
+		if err != nil {
+			return nil, cobra.ShellCompDirectiveError
+		}
+
+		var clusterNames []string
+		for _, c := range clusters {
+			// retrieve status from provider
+			conf := &config.UnmanagedClusterConfig{
+				Provider: c.Provider,
+			}
+			clusterManager := cluster.NewClusterManager(conf)
+			kc, err := clusterManager.Get(c.Name)
+
+			if err != nil {
+				continue
+			}
+
+			// Only complete clusters of the right status, or if the status is unknown.
+			// A value of clusterAnyStatus indicates a request for all clusters.
+			if kc.Status == clusterStatus || kc.Status == cluster.StatusUnknown || clusterStatus == clusterAnyStatus {
+				clusterNames = append(clusterNames, fmt.Sprintf("%s\tstatus: %s - provider: %s", c.Name, kc.Status, c.Provider))
+			}
+		}
+		return clusterNames, cobra.ShellCompDirectiveNoFileComp
+	}
+}

cli/cmd/plugin/unmanaged-cluster/main.go

@@ -9,6 +9,7 @@ import (
 
 	"github.com/vmware-tanzu/community-edition/cli/cmd/plugin"
 	"github.com/vmware-tanzu/community-edition/cli/cmd/plugin/unmanaged-cluster/cmd"
+	"github.com/vmware-tanzu/community-edition/cli/cmd/plugin/unmanaged-cluster/completion"
 )
 
 var description = `Deploy and manage single-node, static, Tanzu clusters.`
@@ -48,6 +49,7 @@ func main() {
 	)
 
 	cmd.SetupRootCommand(p.Cmd)
+	completion.Setup(p.Cmd)
 
 	if err := p.Execute(); err != nil {
 		os.Exit(1)