Adding upstream version 1.2.3.

Signed-off-by: Daniel Baumann <daniel@debian.org>

selfupdate/update.go

@@ -0,0 +1,181 @@
+package selfupdate
+
+import (
+	"bytes"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"os"
+	"path/filepath"
+	"runtime"
+	"strings"
+
+	"github.com/blang/semver"
+	"github.com/inconshreveable/go-update"
+)
+
+func uncompressAndUpdate(src io.Reader, assetURL, cmdPath string) error {
+	_, cmd := filepath.Split(cmdPath)
+	asset, err := UncompressCommand(src, assetURL, cmd)
+	if err != nil {
+		return err
+	}
+
+	log.Println("Will update", cmdPath, "to the latest downloaded from", assetURL)
+	return update.Apply(asset, update.Options{
+		TargetPath: cmdPath,
+	})
+}
+
+func (up *Updater) downloadDirectlyFromURL(assetURL string) (io.ReadCloser, error) {
+	req, err := http.NewRequest("GET", assetURL, nil)
+	if err != nil {
+		return nil, fmt.Errorf("Failed to create HTTP request to %s: %s", assetURL, err)
+	}
+
+	req.Header.Add("Accept", "application/octet-stream")
+	req = req.WithContext(up.apiCtx)
+
+	// OAuth HTTP client is not available to download blob from URL when the URL is a redirect URL
+	// returned from GitHub Releases API (response status 400).
+	// Use default HTTP client instead.
+	res, err := http.DefaultClient.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("Failed to download a release file from %s: %s", assetURL, err)
+	}
+
+	if res.StatusCode != 200 {
+		return nil, fmt.Errorf("Failed to download a release file from %s: Not successful status %d", assetURL, res.StatusCode)
+	}
+
+	return res.Body, nil
+}
+
+// UpdateTo downloads an executable from GitHub Releases API and replace current binary with the downloaded one.
+// It downloads a release asset via GitHub Releases API so this function is available for update releases on private repository.
+// If a redirect occurs, it fallbacks into directly downloading from the redirect URL.
+func (up *Updater) UpdateTo(rel *Release, cmdPath string) error {
+	var client http.Client
+	src, redirectURL, err := up.api.Repositories.DownloadReleaseAsset(up.apiCtx, rel.RepoOwner, rel.RepoName, rel.AssetID, &client)
+	if err != nil {
+		return fmt.Errorf("Failed to call GitHub Releases API for getting an asset(ID: %d) for repository '%s/%s': %s", rel.AssetID, rel.RepoOwner, rel.RepoName, err)
+	}
+	if redirectURL != "" {
+		log.Println("Redirect URL was returned while trying to download a release asset from GitHub API. Falling back to downloading from asset URL directly:", redirectURL)
+		src, err = up.downloadDirectlyFromURL(redirectURL)
+		if err != nil {
+			return err
+		}
+	}
+	defer src.Close()
+
+	data, err := ioutil.ReadAll(src)
+	if err != nil {
+		return fmt.Errorf("Failed reading asset body: %v", err)
+	}
+
+	if up.validator == nil {
+		return uncompressAndUpdate(bytes.NewReader(data), rel.AssetURL, cmdPath)
+	}
+
+	validationSrc, validationRedirectURL, err := up.api.Repositories.DownloadReleaseAsset(up.apiCtx, rel.RepoOwner, rel.RepoName, rel.ValidationAssetID, &client)
+	if err != nil {
+		return fmt.Errorf("Failed to call GitHub Releases API for getting an validation asset(ID: %d) for repository '%s/%s': %s", rel.ValidationAssetID, rel.RepoOwner, rel.RepoName, err)
+	}
+	if validationRedirectURL != "" {
+		log.Println("Redirect URL was returned while trying to download a release validation asset from GitHub API. Falling back to downloading from asset URL directly:", redirectURL)
+		validationSrc, err = up.downloadDirectlyFromURL(validationRedirectURL)
+		if err != nil {
+			return err
+		}
+	}
+
+	defer validationSrc.Close()
+
+	validationData, err := ioutil.ReadAll(validationSrc)
+	if err != nil {
+		return fmt.Errorf("Failed reading validation asset body: %v", err)
+	}
+
+	if err := up.validator.Validate(data, validationData); err != nil {
+		return fmt.Errorf("Failed validating asset content: %v", err)
+	}
+
+	return uncompressAndUpdate(bytes.NewReader(data), rel.AssetURL, cmdPath)
+}
+
+// UpdateCommand updates a given command binary to the latest version.
+// 'slug' represents 'owner/name' repository on GitHub and 'current' means the current version.
+func (up *Updater) UpdateCommand(cmdPath string, current semver.Version, slug string) (*Release, error) {
+	if runtime.GOOS == "windows" && !strings.HasSuffix(cmdPath, ".exe") {
+		// Ensure to add '.exe' to given path on Windows
+		cmdPath = cmdPath + ".exe"
+	}
+
+	stat, err := os.Lstat(cmdPath)
+	if err != nil {
+		return nil, fmt.Errorf("Failed to stat '%s'. File may not exist: %s", cmdPath, err)
+	}
+	if stat.Mode()&os.ModeSymlink != 0 {
+		p, err := filepath.EvalSymlinks(cmdPath)
+		if err != nil {
+			return nil, fmt.Errorf("Failed to resolve symlink '%s' for executable: %s", cmdPath, err)
+		}
+		cmdPath = p
+	}
+
+	rel, ok, err := up.DetectLatest(slug)
+	if err != nil {
+		return nil, err
+	}
+	if !ok {
+		log.Println("No release detected. Current version is considered up-to-date")
+		return &Release{Version: current}, nil
+	}
+	if current.Equals(rel.Version) {
+		log.Println("Current version", current, "is the latest. Update is not needed")
+		return rel, nil
+	}
+	log.Println("Will update", cmdPath, "to the latest version", rel.Version)
+	if err := up.UpdateTo(rel, cmdPath); err != nil {
+		return nil, err
+	}
+	return rel, nil
+}
+
+// UpdateSelf updates the running executable itself to the latest version.
+// 'slug' represents 'owner/name' repository on GitHub and 'current' means the current version.
+func (up *Updater) UpdateSelf(current semver.Version, slug string) (*Release, error) {
+	cmdPath, err := os.Executable()
+	if err != nil {
+		return nil, err
+	}
+	return up.UpdateCommand(cmdPath, current, slug)
+}
+
+// UpdateTo downloads an executable from assetURL and replace the current binary with the downloaded one.
+// This function is low-level API to update the binary. Because it does not use GitHub API and downloads asset directly from the URL via HTTP,
+// this function is not available to update a release for private repositories.
+// cmdPath is a file path to command executable.
+func UpdateTo(assetURL, cmdPath string) error {
+	up := DefaultUpdater()
+	src, err := up.downloadDirectlyFromURL(assetURL)
+	if err != nil {
+		return err
+	}
+	defer src.Close()
+	return uncompressAndUpdate(src, assetURL, cmdPath)
+}
+
+// UpdateCommand updates a given command binary to the latest version.
+// This function is a shortcut version of updater.UpdateCommand.
+func UpdateCommand(cmdPath string, current semver.Version, slug string) (*Release, error) {
+	return DefaultUpdater().UpdateCommand(cmdPath, current, slug)
+}
+
+// UpdateSelf updates the running executable itself to the latest version.
+// This function is a shortcut version of updater.UpdateSelf.
+func UpdateSelf(current semver.Version, slug string) (*Release, error) {
+	return DefaultUpdater().UpdateSelf(current, slug)
+}