helm/cmd/helm/fetch.go

/*
Copyright 2016 The Kubernetes Authors All rights reserved.

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 main

import (
	"fmt"
	"io"
	"io/ioutil"
	"os"
	"path/filepath"

	"github.com/pkg/errors"
	"github.com/spf13/cobra"

	"k8s.io/helm/pkg/chartutil"
	"k8s.io/helm/pkg/downloader"
	"k8s.io/helm/pkg/getter"
	"k8s.io/helm/pkg/repo"
)

const fetchDesc = `
Retrieve a package from a package repository, and download it locally.

This is useful for fetching packages to inspect, modify, or repackage. It can
also be used to perform cryptographic verification of a chart without installing
the chart.

There are options for unpacking the chart after download. This will create a
directory for the chart and uncompress into that directory.

If the --verify flag is specified, the requested chart MUST have a provenance
file, and MUST pass the verification process. Failure in any part of this will
result in an error, and the chart will not be saved locally.
`

type fetchOptions struct {
	caFile      string // --ca-file
	certFile    string // --cert-file
	destdir     string // --destination
	devel       bool   // --devel
	keyFile     string // --key-file
	keyring     string // --keyring
	password    string // --password
	repoURL     string // --repo
	untar       bool   // --untar
	untardir    string // --untardir
	username    string // --username
	verify      bool   // --verify
	verifyLater bool   // --prov
	version     string // --version

	chartRef string
}

func newFetchCmd(out io.Writer) *cobra.Command {
	o := &fetchOptions{}

	cmd := &cobra.Command{
		Use:   "fetch [flags] [chart URL | repo/chartname] [...]",
		Short: "download a chart from a repository and (optionally) unpack it in local directory",
		Long:  fetchDesc,
		RunE: func(cmd *cobra.Command, args []string) error {
			if len(args) == 0 {
				return errors.Errorf("need at least one argument, url or repo/name of the chart")
			}

			if o.version == "" && o.devel {
				debug("setting version to >0.0.0-0")
				o.version = ">0.0.0-0"
			}

			for i := 0; i < len(args); i++ {
				o.chartRef = args[i]
				if err := o.run(out); err != nil {
					return err
				}
			}
			return nil
		},
	}

	f := cmd.Flags()
	f.BoolVar(&o.devel, "devel", false, "use development versions, too. Equivalent to version '>0.0.0-0'. If --version is set, this is ignored.")
	f.BoolVar(&o.untar, "untar", false, "if set to true, will untar the chart after downloading it")
	f.BoolVar(&o.verify, "verify", false, "verify the package against its signature")
	f.BoolVar(&o.verifyLater, "prov", false, "fetch the provenance file, but don't perform verification")
	f.StringVar(&o.caFile, "ca-file", "", "verify certificates of HTTPS-enabled servers using this CA bundle")
	f.StringVar(&o.certFile, "cert-file", "", "identify HTTPS client using this SSL certificate file")
	f.StringVar(&o.keyFile, "key-file", "", "identify HTTPS client using this SSL key file")
	f.StringVar(&o.keyring, "keyring", defaultKeyring(), "keyring containing public keys")
	f.StringVar(&o.password, "password", "", "chart repository password")
	f.StringVar(&o.repoURL, "repo", "", "chart repository url where to locate the requested chart")
	f.StringVar(&o.untardir, "untardir", ".", "if untar is specified, this flag specifies the name of the directory into which the chart is expanded")
	f.StringVar(&o.username, "username", "", "chart repository username")
	f.StringVar(&o.version, "version", "", "specific version of a chart. Without this, the latest version is fetched")
	f.StringVarP(&o.destdir, "destination", "d", ".", "location to write the chart. If this and tardir are specified, tardir is appended to this")

	return cmd
}

func (o *fetchOptions) run(out io.Writer) error {
	c := downloader.ChartDownloader{
		HelmHome: settings.Home,
		Out:      out,
		Keyring:  o.keyring,
		Verify:   downloader.VerifyNever,
		Getters:  getter.All(settings),
		Username: o.username,
		Password: o.password,
	}

	if o.verify {
		c.Verify = downloader.VerifyAlways
	} else if o.verifyLater {
		c.Verify = downloader.VerifyLater
	}

	// If untar is set, we fetch to a tempdir, then untar and copy after
	// verification.
	dest := o.destdir
	if o.untar {
		var err error
		dest, err = ioutil.TempDir("", "helm-")
		if err != nil {
			return errors.Wrap(err, "failed to untar")
		}
		defer os.RemoveAll(dest)
	}

	if o.repoURL != "" {
		chartURL, err := repo.FindChartInAuthRepoURL(o.repoURL, o.username, o.password, o.chartRef, o.version, o.certFile, o.keyFile, o.caFile, getter.All(settings))
		if err != nil {
			return err
		}
		o.chartRef = chartURL
	}

	saved, v, err := c.DownloadTo(o.chartRef, o.version, dest)
	if err != nil {
		return err
	}

	if o.verify {
		fmt.Fprintf(out, "Verification: %v\n", v)
	}

	// After verification, untar the chart into the requested directory.
	if o.untar {
		ud := o.untardir
		if !filepath.IsAbs(ud) {
			ud = filepath.Join(o.destdir, ud)
		}
		if fi, err := os.Stat(ud); err != nil {
			if err := os.MkdirAll(ud, 0755); err != nil {
				return errors.Wrap(err, "failed to untar (mkdir)")
			}

		} else if !fi.IsDir() {
			return errors.Errorf("failed to untar: %s is not a directory", ud)
		}

		return chartutil.ExpandFile(ud, saved)
	}
	return nil
}

// defaultKeyring returns the expanded path to the default keyring.
func defaultKeyring() string {
	return os.ExpandEnv("$HOME/.gnupg/pubring.gpg")
}