docker-compose/cli/cmd/context/ls.go

/*
   Copyright 2020 Docker, 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 context

import (
	"context"
	"errors"
	"fmt"
	"os"
	"sort"
	"strings"
	"text/tabwriter"

	"github.com/spf13/cobra"

	apicontext "github.com/docker/api/context"
	"github.com/docker/api/context/store"
	"github.com/docker/api/formatter"
)

type lsOpts struct {
	quiet bool
	json  bool
}

func (o lsOpts) validate() error {
	if o.quiet && o.json {
		return errors.New(`cannot combine "quiet" and "json" options`)
	}
	return nil
}

func listCommand() *cobra.Command {
	var opts lsOpts
	cmd := &cobra.Command{
		Use:     "list",
		Short:   "List available contexts",
		Aliases: []string{"ls"},
		Args:    cobra.NoArgs,
		RunE: func(cmd *cobra.Command, args []string) error {
			return runList(cmd.Context(), opts)
		},
	}
	cmd.Flags().BoolVarP(&opts.quiet, "quiet", "q", false, "Only show context names")
	cmd.Flags().BoolVar(&opts.json, "json", false, "Format output as JSON")

	return cmd
}

func runList(ctx context.Context, opts lsOpts) error {
	err := opts.validate()
	if err != nil {
		return err
	}

	currentContext := apicontext.CurrentContext(ctx)
	s := store.ContextStore(ctx)
	contexts, err := s.List()
	if err != nil {
		return err
	}

	sort.Slice(contexts, func(i, j int) bool {
		return strings.Compare(contexts[i].Name, contexts[j].Name) == -1
	})

	if opts.quiet {
		for _, c := range contexts {
			fmt.Println(c.Name)
		}
		return nil
	}

	if opts.json {
		j, err := formatter.ToStandardJSON(contexts)
		if err != nil {
			return err
		}
		fmt.Println(j)
		return nil
	}

	w := tabwriter.NewWriter(os.Stdout, 20, 1, 3, ' ', 0)
	fmt.Fprintln(w, "NAME\tTYPE\tDESCRIPTION\tDOCKER ENDPOINT\tKUBERNETES ENDPOINT\tORCHESTRATOR")
	format := "%s\t%s\t%s\t%s\t%s\t%s\n"

	for _, c := range contexts {
		contextName := c.Name
		if c.Name == currentContext {
			contextName += " *"
		}

		fmt.Fprintf(w,
			format,
			contextName,
			c.Type(),
			c.Metadata.Description,
			getEndpoint("docker", c.Endpoints),
			getEndpoint("kubernetes", c.Endpoints),
			c.Metadata.StackOrchestrator)
	}

	return w.Flush()
}

func getEndpoint(name string, meta map[string]interface{}) string {
	endpoints, ok := meta[name]
	if !ok {
		return ""
	}
	data, ok := endpoints.(*store.Endpoint)
	if !ok {
		return ""
	}

	result := data.Host
	if data.DefaultNamespace != "" {
		result += fmt.Sprintf(" (%s)", data.DefaultNamespace)
	}

	return result
}