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Merge pull request #127 from mackerelio/devide-plugin-code
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Refactor mkr plugin install implementation
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@shibayu36
shibayu36 committed Oct 30, 2017
2 parents db1b786 + e35d9db commit 2303643
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332 changes: 1 addition & 331 deletions plugin/commands.go
View file
Original file line number Diff line number Diff line change
@@ -1,23 +1,6 @@
package plugin

import (
"context"
"encoding/json"
"fmt"
"io"
"io/ioutil"
"os"
"path"
"path/filepath"
"regexp"
"runtime"
"strings"

"net/url"

"github.com/mackerelio/mkr/logger"
"github.com/mholt/archiver"
"github.com/pkg/errors"
"gopkg.in/urfave/cli.v1"
)

Expand All @@ -30,319 +13,6 @@ var CommandPlugin = cli.Command{
check plugin by "mkr plugin install".
`,
Subcommands: []cli.Command{
{
Name: "install",
Usage: "Install a plugin from github or plugin registry",
ArgsUsage: "[--prefix <prefix>] [--overwrite] <install_target>",
Action: doPluginInstall,
Flags: []cli.Flag{
cli.StringFlag{
Name: "prefix",
Usage: "Plugin install location. The default is /opt/mackerel-agent/plugins",
},
cli.BoolFlag{
Name: "overwrite",
Usage: "Overwrite a plugin command in a plugin directory, even if same name command exists",
},
},
Description: `
Install a mackerel plugin and a check plugin from github or plugin registry.
To install by mkr, a plugin has to be released to Github Releases in specification format.
<install_target> is:
- <owner>/<repo>[@<release_tag>]
Install from specified github owner, repository, and Github Releases tag.
If you omit <release_tag>, the installer install from latest Github Release.
Example: mkr plugin install mackerelio/mackerel-plugin-sample@v0.0.1
- <plugin_name>[@<release_tag]
Install from plugin registry.
You can find available plugins in https://github.com/mackerelio/plugin-registry
Example: mkr plugin install mackerel-plugin-sample
The installer uses Github API to find the latest release. Please set a github token to
GITHUB_TOKEN environment variable, or to github.token in .gitconfig.
Otherwise, installation sometimes fails because of Github API Rate Limit.
If you want to use the plugin installer by a server provisioning tool,
we recommend you to specify <release_tag> explicitly.
If you specify <release_tag>, the installer doesn't use Github API,
so Github API Rate Limit error doesn't occur.
`,
},
commandPluginInstall,
},
}

// main function for mkr plugin install
func doPluginInstall(c *cli.Context) error {
argInstallTarget := c.Args().First()
if argInstallTarget == "" {
return fmt.Errorf("Specify install target")
}

it, err := newInstallTargetFromString(argInstallTarget)
if err != nil {
return errors.Wrap(err, "Failed to install plugin while parsing install target")
}

pluginDir, err := setupPluginDir(c.String("prefix"))
if err != nil {
return errors.Wrap(err, "Failed to install plugin while setup plugin directory")
}

// Create a work directory for downloading and extracting an artifact
workdir, err := ioutil.TempDir(filepath.Join(pluginDir, "work"), "mkr-plugin-installer-")
if err != nil {
return errors.Wrap(err, "Failed to install plugin while creating a work directory")
}
defer os.RemoveAll(workdir)

// Download an artifact and install by it
downloadURL, err := it.makeDownloadURL()
if err != nil {
return errors.Wrap(err, "Failed to install plugin while making a download URL")
}
artifactFile, err := downloadPluginArtifact(downloadURL, workdir)
if err != nil {
return errors.Wrap(err, "Failed to install plugin while downloading an artifact")
}
err = installByArtifact(artifactFile, filepath.Join(pluginDir, "bin"), workdir, c.Bool("overwrite"))
if err != nil {
return errors.Wrap(err, "Failed to install plugin while extracting and placing")
}

logger.Log("", fmt.Sprintf("Successfully installed %s", argInstallTarget))
return nil
}

// Create a directory for plugin install
func setupPluginDir(pluginDir string) (string, error) {
if pluginDir == "" {
pluginDir = "/opt/mackerel-agent/plugins"
}
err := os.MkdirAll(filepath.Join(pluginDir, "bin"), 0755)
if err != nil {
return "", err
}
err = os.MkdirAll(filepath.Join(pluginDir, "work"), 0755)
if err != nil {
return "", err
}
return pluginDir, nil
}

// Download plugin artifact from `u`(URL) to `workdir`,
// and returns downloaded filepath
func downloadPluginArtifact(u, workdir string) (fpath string, err error) {
logger.Log("", fmt.Sprintf("Downloading %s", u))

// Create request to download
resp, err := (&client{}).get(u)
if err != nil {
return "", err
}
defer resp.Body.Close()

// fpath is filepath where artifact will be saved
fpath = filepath.Join(workdir, path.Base(u))

// download artifact
file, err := os.OpenFile(fpath, os.O_RDWR|os.O_CREATE|os.O_TRUNC, 0644)
if err != nil {
return "", err
}
defer file.Close()

_, err = io.Copy(file, resp.Body)
if err != nil {
return "", err
}

return fpath, nil
}

// Extract artifact and install plugin
func installByArtifact(artifactFile, bindir, workdir string, overwrite bool) error {
// unzip artifact to work directory
err := archiver.Zip.Open(artifactFile, workdir)
if err != nil {
return err
}

// Look for plugin files recursively, and place those to binPath
return filepath.Walk(workdir, func(path string, info os.FileInfo, err error) error {
if err != nil {
return err
}
if info.IsDir() {
return nil
}

// a plugin file should be executable, and have specified name.
name := info.Name()
isExecutable := (info.Mode() & 0111) != 0
if isExecutable && looksLikePlugin(name) {
return placePlugin(path, filepath.Join(bindir, name), overwrite)
}

// `path` is a file but not plugin.
return nil
})
}

func looksLikePlugin(name string) bool {
return strings.HasPrefix(name, "check-") || strings.HasPrefix(name, "mackerel-plugin-")
}

func placePlugin(src, dest string, overwrite bool) error {
_, err := os.Stat(dest)
if err == nil && !overwrite {
logger.Log("", fmt.Sprintf("%s already exists. Skip installing for now", dest))
return nil
}
logger.Log("", fmt.Sprintf("Installing %s", dest))
return os.Rename(src, dest)
}

type installTarget struct {
owner string
repo string
pluginName string
releaseTag string

// fields for testing
rawGithubURL string
apiGithubURL string
}

const (
defaultRawGithubURL = "https://raw.githubusercontent.com"
defaultAPIGithubURL = "https://api.github.com"
)

// the pattern of installTarget string
// (?:<plugin_name>|<owner>/<repo>)(?:@<releaseTag>)?
var targetReg = regexp.MustCompile(`^(?:([^@/]+)/([^@/]+)|([^@/]+))(?:@(.+))?$`)

// Parse install target string, and construct installTarget
// example is below
// - mackerelio/mackerel-plugin-sample
// - mackerel-plugin-sample
// - mackerelio/mackerel-plugin-sample@v0.0.1
func newInstallTargetFromString(target string) (*installTarget, error) {
matches := targetReg.FindStringSubmatch(target)
if len(matches) != 5 {
return nil, fmt.Errorf("Install target is invalid: %s", target)
}

it := &installTarget{
owner: matches[1],
repo: matches[2],
pluginName: matches[3],
releaseTag: matches[4],
}
return it, nil
}

// Make artifact's download URL
func (it *installTarget) makeDownloadURL() (string, error) {
owner, repo, err := it.getOwnerAndRepo()
if err != nil {
return "", err
}

releaseTag, err := it.getReleaseTag(owner, repo)
if err != nil {
return "", err
}

filename := fmt.Sprintf("%s_%s_%s.zip", url.PathEscape(repo), runtime.GOOS, runtime.GOARCH)
downloadURL := fmt.Sprintf(
"https://github.com/%s/%s/releases/download/%s/%s",
url.PathEscape(owner),
url.PathEscape(repo),
url.PathEscape(releaseTag),
filename,
)

return downloadURL, nil
}

func (it *installTarget) getOwnerAndRepo() (string, string, error) {
if it.owner != "" && it.repo != "" {
return it.owner, it.repo, nil
}

// Get owner and repo from plugin registry
defURL := fmt.Sprintf(
"%s/mackerelio/plugin-registry/master/plugins/%s.json",
it.getRawGithubURL(),
url.PathEscape(it.pluginName),
)
resp, err := (&client{}).get(defURL)
if err != nil {
return "", "", err
}
defer resp.Body.Close()

var def registryDef
err = json.NewDecoder(resp.Body).Decode(&def)
if err != nil {
return "", "", err
}

ownerAndRepo := strings.Split(def.Source, "/")
if len(ownerAndRepo) != 2 {
return "", "", fmt.Errorf("source definition is invalid")
}

// Cache owner and repo
it.owner = ownerAndRepo[0]
it.repo = ownerAndRepo[1]

return it.owner, it.repo, nil
}

func (it *installTarget) getReleaseTag(owner, repo string) (string, error) {
if it.releaseTag != "" {
return it.releaseTag, nil
}

// Get latest release tag from Github API
ctx := context.Background()
client := getGithubClient(ctx)
client.BaseURL = it.getAPIGithubURL()

release, _, err := client.Repositories.GetLatestRelease(ctx, owner, repo)
if err != nil {
return "", err
}

// Cache releaseTag
it.releaseTag = release.GetTagName()
return it.releaseTag, nil
}

func (it *installTarget) getRawGithubURL() string {
if it.rawGithubURL != "" {
return it.rawGithubURL
}
return defaultRawGithubURL
}

// Returns URL object which Github Client.BaseURL can receive as it is
func (it *installTarget) getAPIGithubURL() *url.URL {
u := defaultAPIGithubURL
if it.apiGithubURL != "" {
u = it.apiGithubURL
}
// Ignore err because apiGithubURL is specified only internally
apiURL, _ := url.Parse(u + "/") // trailing `/` is required for BaseURL
return apiURL
}

// registryDef represents one plugin definition in plugin-registry
// See Also: https://github.com/mackerelio/plugin-registry
type registryDef struct {
Source string `json:"source"`
Description string `json:"description"`
}
2 changes: 1 addition & 1 deletion plugin/github_test.go
View file
Original file line number Diff line number Diff line change
Expand Up @@ -20,7 +20,7 @@ func githubTestSetup() func() {
origGitConfigEnv := os.Getenv("GIT_CONFIG")
os.Unsetenv("GIT_CONFIG")

return func () {
return func() {
os.Setenv("GITHUB_TOKEN", origTokenEnv)
os.Setenv("GIT_CONFIG", origGitConfigEnv)
}
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