Add support for external modules

This commmit adds support to define and use external modules for custom migration steps.

Signed-off-by: Tobias Wolf <[email protected]>

Dockerfile

@@ -27,6 +27,7 @@ LABEL org.opencontainers.image.source="https://github.com/SovereignCloudStack/ro
 
 ARG ROOKIFY_VERSION=0.0.0.dev1
 ENV ROOKIFY_VERSION=$ROOKIFY_VERSION
+ENV PYTHONPATH="${PYTHONPATH}:/app/rookify/src"
 
 WORKDIR /app/rookify
 

src/rookify/modules/__init__.py

@@ -30,7 +30,16 @@ def _load_module(machine: Machine, config: Dict[str, Any], module_name: str) ->
     :return: returns tuple of preflight_modules, modules
     """
 
-    module = importlib.import_module("rookify.modules.{0}".format(module_name))
+    if "." in module_name:
+        absolute_module_name = module_name
+    else:
+        absolute_module_name = "rookify.modules.{0}".format(module_name)
+
+    try:
+        module = importlib.import_module(absolute_module_name)
+    except ModuleNotFoundError as e:
+        raise ModuleLoadException(module_name, str(e))
+
     additional_modules = []
 
     if not hasattr(module, "ModuleHandler") or not callable(
@@ -63,6 +72,11 @@ def load_modules(machine: Machine, config: Dict[str, Any]) -> None:
             migration_modules.remove(entry.name)
             _load_module(machine, config, entry.name)
 
+    for migration_module in migration_modules.copy():
+        if "." in migration_module:
+            migration_modules.remove(migration_module)
+            _load_module(machine, config, migration_module)
+
     if len(migration_modules) > 0 or len(config["migration_modules"]) < 1:
         logger = get_logger()