Retry downloading external deb packages (#957)

scale_build/image/update.py

@@ -7,6 +7,7 @@ import requests
 import shutil
 import stat
 import tempfile
+import time
 
 from scale_build.config import SIGNING_KEY, SIGNING_PASSWORD
 from scale_build.extensions import build_extensions as do_build_extensions
@@ -200,6 +201,7 @@ def download_and_install_deb_package(package_name, download_url, deb_filename, p
         logger.info(f'Downloading {package_name} from {download_url}')
 
         # Download the package using requests
+        for retry in itertools.count(1):
             try:
                 response = requests.get(download_url, stream=True, timeout=60, allow_redirects=True)
                 response.raise_for_status()
@@ -212,7 +214,10 @@ def download_and_install_deb_package(package_name, download_url, deb_filename, p
 
             except requests.exceptions.RequestException as e:
                 logger.error(f'Failed to download {package_name}: {e}')
-            raise RuntimeError(f'Failed to download {package_name} from {download_url}: {e}')
+                if retry >= 5:
+                    raise RuntimeError(f'Failed to download {package_name} from {download_url}: {e}') from None
+                else:
+                    time.sleep(10)
 
         # Verify the downloaded file exists and has content
         if not os.path.exists(deb_path) or os.path.getsize(deb_path) == 0: