Function FetchGoVersion

releng/prepare-release-branch/internal/run/run.go:116–143

FetchGoVersion fetches the Go version string from the given URL. Returns ErrBranchNotFound if the release branch does not exist (HTTP 404).

(ctx context.Context, url string)

// FetchGoVersion fetches the Go version string from the given URL.
// Returns ErrBranchNotFound if the release branch does not exist (HTTP 404).
func FetchGoVersion(ctx context.Context, url string) (string, error) {
	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, http.NoBody)
	if err != nil {
		return "", fmt.Errorf("creating request: %w", err)
	}

	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		return "", fmt.Errorf("fetching Go version: %w", err)
	}

	defer func() { _ = resp.Body.Close() }()

	if resp.StatusCode == http.StatusNotFound {
		return "", fmt.Errorf("%w: %s", ErrBranchNotFound, url)
	}

	if resp.StatusCode != http.StatusOK {
		return "", fmt.Errorf("%w: %d", ErrHTTPStatus, resp.StatusCode)
	}

	body, err := io.ReadAll(resp.Body)
	if err != nil {
		return "", fmt.Errorf("reading Go version response: %w", err)
	}

	return strings.TrimSpace(string(body)), nil
}