[Code Engine] Allow to build the default runtime with Python 3.13 (#1415)

Author: JosepSampe

CHANGELOG.md

@@ -12,6 +12,7 @@
 - [Standalone] Fixed an issue causing workers to stop prematurely in Consume mode
 - [Invoker] Reduced the number of threads used in the async FaaS Invoker
 - [Monitoring] Fixed token bucket issue that prevented generating the correct number of tokens
+- [Code Engine] Allow to build the default runtime with Python 3.13
 
 
 ## [v3.5.1]

lithops/serverless/backends/code_engine/code_engine.py

@@ -282,8 +282,10 @@ def _build_default_runtime(self, default_runtime_img_name):
         """
         # Build default runtime using local dokcer
         dockerfile = "Dockefile.default-ce-runtime"
+        python_version = utils.CURRENT_PY_VERSION
+        base_image = "slim-buster" if int(python_version.split('.')[1]) < 13 else "bookworm"
         with open(dockerfile, 'w') as f:
-            f.write(f"FROM python:{utils.CURRENT_PY_VERSION}-slim-buster\n")
+            f.write(f"FROM python:{python_version}-{base_image}\n")
             f.write(config.DOCKERFILE_DEFAULT)
         try:
             self.build_runtime(default_runtime_img_name, dockerfile)