A script to download and install the latest release of a github package

This commit is contained in:
Nick Craig-Wood 2018-02-28 10:25:56 +00:00
parent fc32fee4ad
commit d41017a277

239
bin/get-github-release.go Normal file
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// +build ignore
// Get the latest release from a github project
package main
import (
"encoding/json"
"flag"
"io"
"log"
"net/http"
"os"
"os/exec"
"path/filepath"
"regexp"
"strings"
"time"
"golang.org/x/sys/unix"
)
var (
// Flags
install = flag.Bool("install", false, "Install the downloaded package using sudo dpkg -i.")
extract = flag.String("extract", "", "Extract the named executable from the .tar.gz and install into bindir.")
bindir = flag.String("bindir", defaultBinDir(), "Directory to install files downloaded with -extract.")
// Globals
matchProject = regexp.MustCompile(`^(\w+)/(\w+)$`)
)
// A github release
//
// Made by pasting the JSON into https://mholt.github.io/json-to-go/
type Release struct {
URL string `json:"url"`
AssetsURL string `json:"assets_url"`
UploadURL string `json:"upload_url"`
HTMLURL string `json:"html_url"`
ID int `json:"id"`
TagName string `json:"tag_name"`
TargetCommitish string `json:"target_commitish"`
Name string `json:"name"`
Draft bool `json:"draft"`
Author struct {
Login string `json:"login"`
ID int `json:"id"`
AvatarURL string `json:"avatar_url"`
GravatarID string `json:"gravatar_id"`
URL string `json:"url"`
HTMLURL string `json:"html_url"`
FollowersURL string `json:"followers_url"`
FollowingURL string `json:"following_url"`
GistsURL string `json:"gists_url"`
StarredURL string `json:"starred_url"`
SubscriptionsURL string `json:"subscriptions_url"`
OrganizationsURL string `json:"organizations_url"`
ReposURL string `json:"repos_url"`
EventsURL string `json:"events_url"`
ReceivedEventsURL string `json:"received_events_url"`
Type string `json:"type"`
SiteAdmin bool `json:"site_admin"`
} `json:"author"`
Prerelease bool `json:"prerelease"`
CreatedAt time.Time `json:"created_at"`
PublishedAt time.Time `json:"published_at"`
Assets []struct {
URL string `json:"url"`
ID int `json:"id"`
Name string `json:"name"`
Label string `json:"label"`
Uploader struct {
Login string `json:"login"`
ID int `json:"id"`
AvatarURL string `json:"avatar_url"`
GravatarID string `json:"gravatar_id"`
URL string `json:"url"`
HTMLURL string `json:"html_url"`
FollowersURL string `json:"followers_url"`
FollowingURL string `json:"following_url"`
GistsURL string `json:"gists_url"`
StarredURL string `json:"starred_url"`
SubscriptionsURL string `json:"subscriptions_url"`
OrganizationsURL string `json:"organizations_url"`
ReposURL string `json:"repos_url"`
EventsURL string `json:"events_url"`
ReceivedEventsURL string `json:"received_events_url"`
Type string `json:"type"`
SiteAdmin bool `json:"site_admin"`
} `json:"uploader"`
ContentType string `json:"content_type"`
State string `json:"state"`
Size int `json:"size"`
DownloadCount int `json:"download_count"`
CreatedAt time.Time `json:"created_at"`
UpdatedAt time.Time `json:"updated_at"`
BrowserDownloadURL string `json:"browser_download_url"`
} `json:"assets"`
TarballURL string `json:"tarball_url"`
ZipballURL string `json:"zipball_url"`
Body string `json:"body"`
}
// checks if a path has write access
func writable(path string) bool {
return unix.Access(path, unix.W_OK) == nil
}
// Directory to install releases in by default
//
// Find writable directories on $PATH. Use the first writable
// directory which is in $HOME or failing that the first writable
// directory.
//
// Returns "" if none of the above were found
func defaultBinDir() string {
home := os.Getenv("HOME")
var binDir string
for _, dir := range strings.Split(os.Getenv("PATH"), ":") {
if writable(dir) {
if strings.HasPrefix(dir, home) {
return dir
}
if binDir != "" {
binDir = dir
}
}
}
return binDir
}
// Get an asset URL and name
func getAsset(project string, matchName *regexp.Regexp) (string, string) {
url := "https://api.github.com/repos/" + project + "/releases/latest"
log.Printf("Fetching asset info for %q from %q", project, url)
resp, err := http.Get(url)
if err != nil {
log.Fatalf("Failed to fetch release info %q: %v", url, err)
}
if resp.StatusCode != http.StatusOK {
log.Fatalf("Bad status %d when fetching %q release info: %s", resp.StatusCode, url, resp.Status)
}
var release Release
err = json.NewDecoder(resp.Body).Decode(&release)
if err != nil {
log.Fatalf("Failed to decode release info: %v", err)
}
err = resp.Body.Close()
if err != nil {
log.Fatalf("Failed to close body: %v", err)
}
for _, asset := range release.Assets {
if matchName.MatchString(asset.Name) {
return asset.BrowserDownloadURL, asset.Name
}
}
log.Fatalf("Didn't find asset in info")
return "", ""
}
// get a file for download
func getFile(url, fileName string) {
log.Printf("Downloading %q from %q", fileName, url)
out, err := os.Create(fileName)
if err != nil {
log.Fatalf("Failed to open %q: %v", fileName, err)
}
resp, err := http.Get(url)
if err != nil {
log.Fatalf("Failed to fetch asset %q: %v", url, err)
}
if resp.StatusCode != http.StatusOK {
log.Fatalf("Bad status %d when fetching %q asset: %s", resp.StatusCode, url, resp.Status)
}
n, err := io.Copy(out, resp.Body)
if err != nil {
log.Fatalf("Error while downloading: %v", err)
}
err = resp.Body.Close()
if err != nil {
log.Fatalf("Failed to close body: %v", err)
}
err = out.Close()
if err != nil {
log.Fatalf("Failed to close output file: %v", err)
}
log.Printf("Downloaded %q (%d bytes)", fileName, n)
}
// run a shell command
func run(args ...string) {
cmd := exec.Command(args[0], args[1:]...)
cmd.Stdout = os.Stdout
cmd.Stderr = os.Stderr
err := cmd.Run()
if err != nil {
log.Fatalf("Failed to run %v: %v", args, err)
}
}
func main() {
flag.Parse()
args := flag.Args()
if len(args) != 2 {
log.Fatalf("Syntax: %s <user/project> <name reg exp>", os.Args[0])
}
project, nameRe := args[0], args[1]
if !matchProject.MatchString(project) {
log.Fatalf("Project %q must be in form user/project", project)
}
matchName, err := regexp.Compile(nameRe)
if err != nil {
log.Fatalf("Invalid regexp for name %q: %v", nameRe, err)
}
assetURL, assetName := getAsset(project, matchName)
fileName := filepath.Join(os.TempDir(), assetName)
getFile(assetURL, fileName)
if *install {
log.Printf("Installing %s", fileName)
run("sudo", "dpkg", "--force-bad-version", "-i", fileName)
log.Printf("Installed %s", fileName)
} else if *extract != "" {
if *bindir == "" {
log.Fatalf("Need to set -bindir")
}
log.Printf("Unpacking %s from %s and installing into %s", *extract, fileName, *bindir)
run("tar", "xf", fileName, *extract)
run("chmod", "a+x", *extract)
run("mv", "-f", *extract, *bindir+"/")
}
}