use http get to download file from GitHub

cmd/clusterctl/client/repository/repository_github.go

@@ -156,6 +156,22 @@ func (g *gitHubRepository) ComponentsPath() string {
 
 // GetFile returns a file for a given provider version.
 func (g *gitHubRepository) GetFile(version, path string) ([]byte, error) {
+	cacheID := fmt.Sprintf("%s/%s:%s:%s", g.owner, g.repository, version, path)
+	if content, ok := cacheFiles[cacheID]; ok {
+		return content, nil
+	}
+
+	// Try to get the file using http get.
+	// NOTE: this can be disabled by setting GORPOXY to `direct` or `off` (same knobs used for skipping goproxy requests).
+	if goProxyClient, _ := g.getGoproxyClient(); goProxyClient != nil {
+		if files, err := g.httpGetFilesFromRelease(version, path); err == nil {
+			cacheFiles[cacheID] = files
+			return files, nil
+		}
+	}
+
+	// If the http get request failed (or it is disabled) falls back on using the GITHUB api to download the file
+
 	release, err := g.getReleaseByTag(version)
 	if err != nil {
 		if errors.Is(err, errNotFound) {
@@ -172,6 +188,7 @@ func (g *gitHubRepository) GetFile(version, path string) ([]byte, error) {
 		return nil, errors.Wrapf(err, "failed to download files from GitHub release %s", version)
 	}
 
+	cacheFiles[cacheID] = files
 	return files, nil
 }
 
@@ -379,14 +396,28 @@ func (g *gitHubRepository) getReleaseByTag(tag string) (*github.RepositoryReleas
 	return release, nil
 }
 
-// downloadFilesFromRelease download a file from release.
-func (g *gitHubRepository) downloadFilesFromRelease(release *github.RepositoryRelease, fileName string) ([]byte, error) {
+// httpGetFilesFromRelease gets a file from github using http get.
+func (g *gitHubRepository) httpGetFilesFromRelease(version, fileName string) ([]byte, error) {
 	ctx := context.TODO()
 
-	cacheID := fmt.Sprintf("%s/%s:%s:%s", g.owner, g.repository, *release.TagName, fileName)
-	if content, ok := cacheFiles[cacheID]; ok {
-		return content, nil
+	downloadURL := fmt.Sprintf("https://github.com/%s/%s/releases/download/%s/%s", g.owner, g.repository, version, fileName)
+	var retryError error
+	var content []byte
+	_ = wait.PollUntilContextTimeout(ctx, retryableOperationInterval, retryableOperationTimeout, true, func(ctx context.Context) (bool, error) {
+		if content, retryError = httpGetFile(downloadURL); retryError != nil {
+			return false, retryError
+		}
+		return true, nil
+	})
+	if retryError != nil {
+		return content, retryError
 	}
+	return content, nil
+}
+
+// downloadFilesFromRelease download a file from release.
+func (g *gitHubRepository) downloadFilesFromRelease(release *github.RepositoryRelease, fileName string) ([]byte, error) {
+	ctx := context.TODO()
 
 	client := g.getClient()
 	absoluteFileName := filepath.Join(g.rootPath, fileName)
@@ -441,7 +472,6 @@ func (g *gitHubRepository) downloadFilesFromRelease(release *github.RepositoryRe
 		return nil, retryError
 	}
 
-	cacheFiles[cacheID] = content
 	return content, nil
 }
 
@@ -457,3 +487,42 @@ func (g *gitHubRepository) handleGithubErr(err error, message string, args ...in
 	}
 	return errors.Wrapf(err, message, args...)
 }
+
+func httpGetFile(url string) ([]byte, error) {
+	// create a new HTTP client
+	client := &http.Client{}
+
+	// create a new GET request
+	req, err := http.NewRequestWithContext(context.TODO(), http.MethodGet, url, http.NoBody)
+	if err != nil {
+		return nil, errors.Wrap(err, "error creating request")
+	}
+
+	// send the request and get the response
+	resp, err := client.Do(req)
+	if err != nil {
+		return nil, errors.Wrap(err, "error sending request")
+	}
+	defer resp.Body.Close()
+
+	// check if the response was a redirect
+	if resp.StatusCode >= 300 && resp.StatusCode <= 399 {
+		redirectURL, err := resp.Location()
+		if err != nil {
+			return nil, errors.Wrap(err, "error getting redirect location")
+		}
+
+		// Follow the redirect
+		return httpGetFile(redirectURL.String())
+	}
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, errors.Errorf("error getting file, status code: %d", resp.StatusCode)
+	}
+
+	body, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return nil, errors.Wrap(err, "error reading response body")
+	}
+	return body, nil
+}