enable downloading code deployed to parse

* fetches cloud code for existing app during new app creation
* add a download command that can download the current deployed cloud code

Author: pavanka

commands.go

@@ -29,6 +29,7 @@ http://parse.com`,
 	c.AddCommand(newDefaultCmd(e))
 	c.AddCommand(newDeployCmd(e))
 	c.AddCommand(newDevelopCmd(e))
+	c.AddCommand(newDownloadCmd(e))
 	c.AddCommand(newFunctionHooksCmd(e))
 	c.AddCommand(newGenerateCmd(e))
 	c.AddCommand(newJsSdkCmd(e))

deploy_cmd.go

@@ -309,7 +309,8 @@ type deployInfo struct {
 	ParseVersion string         `json:"parseVersion,omitempty"`
 	Checksums    deployFileData `json:"checksums,omitempty"`
 	Versions     deployFileData `json:"userFiles,omitempty"`
-	Warning      string         `json:"warning,omitempty"`
+	Timestamp    string         `json:"timestamp,omitempty"` // only populated by get from releases
+	Warning      string         `json:"warning,omitempty"`   // only populated by post to deploy
 }
 
 func (d *deployCmd) makeNewRelease(info *deployInfo, e *env) (deployInfo, error) {

download_cmd.go

@@ -0,0 +1,252 @@
+package main
+
+import (
+	"crypto/md5"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net/url"
+	"os"
+	"path"
+	"path/filepath"
+
+	"github.com/facebookgo/errgroup"
+	"github.com/facebookgo/stackerr"
+	"github.com/spf13/cobra"
+)
+
+type downloadCmd struct {
+	force   bool
+	release *deployInfo
+}
+
+func (d *downloadCmd) verifyChecksum(path, checksum string) error {
+	file, err := os.Open(path)
+	if err != nil {
+		return stackerr.Wrap(err)
+	}
+	defer file.Close()
+
+	h := md5.New()
+	_, err = io.Copy(h, file)
+	if err != nil {
+		return stackerr.Wrap(err)
+	}
+
+	sum := fmt.Sprintf("%x", h.Sum(nil))
+	if sum != checksum {
+		return stackerr.Newf("Invalid checksum for %s", path)
+	}
+
+	return nil
+}
+
+func (d *downloadCmd) moveFiles(
+	e *env,
+	tempDir string,
+	release *deployInfo) error {
+	var wg errgroup.Group
+
+	maxParallel := make(chan struct{}, maxOpenFD)
+	wg.Add(len(release.Versions.Cloud) + len(release.Versions.Public))
+
+	moveFile := func(tempDir, kind, file, checksum string) {
+		defer func() {
+			wg.Done()
+			<-maxParallel
+		}()
+
+		err := os.MkdirAll(
+			filepath.Join(e.Root, kind, filepath.Dir(file)),
+			0755,
+		)
+		if err != nil {
+			wg.Error(stackerr.Wrap(err))
+			return
+		}
+
+		err = os.Rename(
+			filepath.Join(tempDir, kind, file),
+			filepath.Join(e.Root, kind, file),
+		)
+		if err != nil {
+			wg.Error(stackerr.Wrap(err))
+			return
+		}
+
+		err = d.verifyChecksum(
+			filepath.Join(e.Root, kind, file),
+			checksum,
+		)
+		if err != nil {
+			wg.Error(err)
+			return
+		}
+	}
+
+	for file, checksum := range release.Checksums.Cloud {
+		maxParallel <- struct{}{}
+		go moveFile(
+			tempDir,
+			cloudDir,
+			file,
+			checksum,
+		)
+	}
+	for file, checksum := range release.Checksums.Public {
+		maxParallel <- struct{}{}
+		go moveFile(
+			tempDir,
+			hostingDir,
+			file,
+			checksum,
+		)
+	}
+	return wg.Wait()
+}
+
+func (d *downloadCmd) download(e *env, tempDir string, release *deployInfo) error {
+	var wg errgroup.Group
+	maxParallel := make(chan struct{}, maxOpenFD)
+	wg.Add(len(release.Versions.Cloud) + len(release.Versions.Public))
+
+	downloadHosted := func(file, version, checksum string) {
+		defer func() {
+			wg.Done()
+			<-maxParallel
+		}()
+
+		v := make(url.Values)
+		v.Set("version", version)
+		v.Set("checksum", checksum)
+		u := &url.URL{
+			Path:     path.Join("hosted_files", file),
+			RawQuery: v.Encode(),
+		}
+		var content []byte
+		_, err := e.ParseAPIClient.Get(u, &content)
+		if err != nil {
+			wg.Error(err)
+			return
+		}
+
+		path := path.Join(tempDir, hostingDir, file)
+		if err := os.MkdirAll(filepath.Dir(path), 0755); err != nil {
+			wg.Error(stackerr.Wrap(err))
+			return
+		}
+		if err := ioutil.WriteFile(path, content, 0644); err != nil {
+			wg.Error(stackerr.Wrap(err))
+			return
+		}
+		if err := d.verifyChecksum(path, checksum); err != nil {
+			wg.Error(err)
+			return
+		}
+	}
+
+	downloadScript := func(file, version, checksum string) {
+		defer func() {
+			wg.Done()
+			<-maxParallel
+		}()
+
+		v := make(url.Values)
+		v.Set("version", version)
+		v.Set("checksum", checksum)
+		u := &url.URL{
+			Path:     path.Join("scripts", file),
+			RawQuery: v.Encode(),
+		}
+		var content string
+		_, err := e.ParseAPIClient.Get(u, &content)
+		if err != nil {
+			wg.Error(err)
+			return
+		}
+
+		path := path.Join(tempDir, cloudDir, file)
+		if err := os.MkdirAll(filepath.Dir(path), 0755); err != nil {
+			wg.Error(stackerr.Wrap(err))
+			return
+		}
+		if err := ioutil.WriteFile(path, []byte(content), 0644); err != nil {
+			wg.Error(stackerr.Wrap(err))
+			return
+		}
+	}
+
+	for file, version := range release.Versions.Public {
+		checksum, ok := release.Checksums.Public[file]
+		if !ok {
+			continue
+		}
+		maxParallel <- struct{}{}
+		go downloadHosted(file, version, checksum)
+	}
+
+	for file, version := range release.Versions.Cloud {
+		checksum, ok := release.Checksums.Cloud[file]
+		if !ok {
+			continue
+		}
+		maxParallel <- struct{}{}
+		go downloadScript(file, version, checksum)
+	}
+
+	return wg.Wait()
+}
+
+func (d *downloadCmd) run(e *env, c *context) error {
+	if d.release == nil {
+		latestRelease, err := (&deployCmd{}).getPrevDeplInfo(e)
+		if err != nil {
+			return err
+		}
+		d.release = latestRelease
+	}
+
+	tempDir, err := ioutil.TempDir("", "parse_code_")
+	if err != nil {
+		return stackerr.Wrap(err)
+	}
+
+	err = d.download(e, tempDir, d.release)
+	if err != nil {
+		fmt.Fprintln(e.Err, "Failed to download Cloud Code.")
+		return stackerr.Wrap(err)
+	}
+	if !d.force {
+		fmt.Fprintf(e.Out, "Successfully downloaded Cloud Code to %q.\n", tempDir)
+		return nil
+	}
+
+	err = d.moveFiles(e, tempDir, d.release)
+	if err != nil {
+		fmt.Fprintf(
+			e.Out,
+			`Failed to download Cloud Code to %q.
+Sorry! but %s might have corrupted contents.
+If you want to download Cloud Code from Parse,
+try again without the "-f" option.
+`,
+			e.Root,
+			e.Root,
+		)
+		return stackerr.Wrap(err)
+	}
+	return nil
+}
+
+func newDownloadCmd(e *env) *cobra.Command {
+	d := &downloadCmd{}
+	cmd := &cobra.Command{
+		Use:   "download [app]",
+		Short: "Downloads the Cloud Code project",
+		Long:  "Downloads the Cloud Code project at a temporary location.",
+		Run:   runWithClient(e, d.run),
+	}
+	cmd.Flags().BoolVarP(&d.force, "force", "f", d.force,
+		"Force will overwrite any content in the current project directory")
+	return cmd
+}