Refactor/documentation round for platydock.

platypush/platydock/__init__.py

@@ -10,7 +10,7 @@ import pathlib
 import re
 import sys
 import textwrap
-from typing import Iterable
+from typing import Iterable, Sequence
 
 from platypush.config import Config
 from platypush.utils.manifest import (
@@ -70,7 +70,6 @@ class DockerfileGenerator:
         """
         Generate a Dockerfile based on a configuration file.
 
-        :param cfgfile: Path to the configuration file.
         :return: The content of the generated Dockerfile.
         """
         import platypush
@@ -131,6 +130,11 @@ class DockerfileGenerator:
         return '\n'.join(new_file_lines)
 
     def _generate_git_clone_command(self) -> str:
+        """
+        Generates a git clone command in Dockerfile that checks out the repo
+        and the right git reference, if the application sources aren't already
+        available under /install.
+        """
         pkg_manager = self._pkg_manager_by_base_image[self.image]
         install_cmd = ' '.join(pkg_manager.value.install)
         uninstall_cmd = ' '.join(pkg_manager.value.uninstall)
@@ -148,26 +152,13 @@ class DockerfileGenerator:
             """
         )
 
-    @staticmethod
-    def _get_exposed_ports() -> Iterable[int]:
+    @classmethod
+    def from_cmdline(cls, args: Sequence[str]) -> 'DockerfileGenerator':
         """
-        :return: The listen ports used by the backends enabled in the configuration
-            file.
-        """
-        backends_config = Config.get_backends()
-        return {
-            int(port)
-            for port in (
-                backends_config.get('http', {}).get('port'),
-                backends_config.get('tcp', {}).get('port'),
-            )
-            if port
-        }
+        Create a DockerfileGenerator instance from command line arguments.
 
-
-def main():
-    """
-    Generates a Dockerfile based on the configuration file.
+        :param args: Command line arguments.
+        :return: A DockerfileGenerator instance.
         """
         parser = argparse.ArgumentParser(
             prog='platydock',
@@ -210,10 +201,10 @@ def main():
             'option which branch, tag or commit hash to use. Defaults to master.',
         )
 
-    opts, _ = parser.parse_known_args(sys.argv[1:])
+        opts, _ = parser.parse_known_args(args)
         if opts.show_usage:
             parser.print_help()
-        return 0
+            sys.exit(0)
 
         if not opts.cfgfile:
             opts.cfgfile = os.path.join(
@@ -226,11 +217,30 @@ def main():
                 file=sys.stderr,
             )
 
-    dockerfile = DockerfileGenerator(
-        opts.cfgfile, image=opts.image, gitref=opts.gitref
-    ).generate()
+        return cls(opts.cfgfile, image=opts.image, gitref=opts.gitref)
 
-    print(dockerfile)
+    @staticmethod
+    def _get_exposed_ports() -> Iterable[int]:
+        """
+        :return: The listen ports used by the backends enabled in the configuration
+            file.
+        """
+        backends_config = Config.get_backends()
+        return {
+            int(port)
+            for port in (
+                backends_config.get('http', {}).get('port'),
+                backends_config.get('tcp', {}).get('port'),
+            )
+            if port
+        }
+
+
+def main():
+    """
+    Generates a Dockerfile based on the configuration file.
+    """
+    print(DockerfileGenerator.from_cmdline(sys.argv[1:]).generate())
     return 0