commands.go

/*
   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 commands

import (
	"encoding/json"
	"fmt"
	"os"
	"path/filepath"
	"strings"

	"github.com/containerd/containerd"
	"github.com/urfave/cli"
)

var (
	// SnapshotterFlags are cli flags specifying snapshotter names
	SnapshotterFlags = []cli.Flag{
		cli.StringFlag{
			Name:   "snapshotter",
			Usage:  "snapshotter name. Empty value stands for the default value.",
			Value:  containerd.DefaultSnapshotter,
			EnvVar: "CONTAINERD_SNAPSHOTTER",
		},
	}

	// LabelFlag is a cli flag specifying labels
	LabelFlag = cli.StringSliceFlag{
		Name:  "label",
		Usage: "labels to attach to the image",
	}

	// RegistryFlags are cli flags specifying registry options
	RegistryFlags = []cli.Flag{
		cli.BoolFlag{
			Name:  "skip-verify,k",
			Usage: "skip SSL certificate validation",
		},
		cli.BoolFlag{
			Name:  "plain-http",
			Usage: "allow connections using plain HTTP",
		},
		cli.StringFlag{
			Name:  "user,u",
			Usage: "user[:password] Registry user and password",
		},
		cli.StringFlag{
			Name:  "refresh",
			Usage: "refresh token for authorization server",
		},
	}
)

// ObjectWithLabelArgs returns the first arg and a LabelArgs object
func ObjectWithLabelArgs(clicontext *cli.Context) (string, map[string]string) {
	var (
		first        = clicontext.Args().First()
		labelStrings = clicontext.Args().Tail()
	)

	return first, LabelArgs(labelStrings)
}

// LabelArgs returns a map of label key,value pairs
func LabelArgs(labelStrings []string) map[string]string {
	labels := make(map[string]string, len(labelStrings))
	for _, label := range labelStrings {
		parts := strings.SplitN(label, "=", 2)
		key := parts[0]
		value := "true"
		if len(parts) > 1 {
			value = parts[1]
		}

		labels[key] = value
	}

	return labels
}

// PrintAsJSON prints input in JSON format
func PrintAsJSON(x interface{}) {
	b, err := json.MarshalIndent(x, "", "    ")
	if err != nil {
		fmt.Fprintf(os.Stderr, "can't marshal %+v as a JSON string: %v\n", x, err)
	}
	fmt.Println(string(b))
}

// WritePidFile writes the pid atomically to a file
func WritePidFile(path string, pid int) error {
	path, err := filepath.Abs(path)
	if err != nil {
		return err
	}
	tempPath := filepath.Join(filepath.Dir(path), fmt.Sprintf(".%s", filepath.Base(path)))
	f, err := os.OpenFile(tempPath, os.O_RDWR|os.O_CREATE|os.O_EXCL|os.O_SYNC, 0666)
	if err != nil {
		return err
	}
	_, err = fmt.Fprintf(f, "%d", pid)
	f.Close()
	if err != nil {
		return err
	}
	return os.Rename(tempPath, path)
}