Allow for passing in --with-plugins to the alembic gmg subcommand.

This allows plugin writers to easily take advantage off alembic's migration
autogeneration support.

* mediagoblin/gmg_commands/alembic_commands.py: Adjusted imports.
  (FudgedCommandLine.main, parser_setup): Add support for importing
  plugins when --with-plugins is passed in.

1 files changed, 19 insertions, 0 deletions

diff --git a/mediagoblin/gmg_commands/alembic_commands.py b/mediagoblin/gmg_commands/alembic_commands.py
index 58b931dc..dc679f22 100644
--- a/mediagoblin/gmg_commands/alembic_commands.py
+++ b/mediagoblin/gmg_commands/alembic_commands.py
@@ -22,17 +22,33 @@ from sqlalchemy.orm import sessionmaker
 from mediagoblin.db.open import setup_connection_and_db_from_config
 from mediagoblin.init import setup_global_and_app_config
 from mediagoblin.db.migration_tools import build_alembic_config
+from mediagoblin.tools.common import import_component
 
 
 class FudgedCommandLine(config.CommandLine):
     def main(self, args, db, global_config):
         options = self.parser.parse_args(args.args_for_alembic)
+
+        # This is useful for people running commands involving plugins, such
+        # as building autogenerated revisions.
+        if args.with_plugins:
+            plugins = global_config.get('plugins', {}).keys()
+            for plugin in plugins:
+                print(plugin)
+                try:
+                    import_component('{0}.models:MODELS'.format(plugin))
+                except ImportError:
+                    # It doesn't really matter if there's no models to import
+                    # here.
+                    pass
+
         # This code is inspired by a hack in Alembic, but isn't the same really.
         # Regardless, Alembic is Expat licensed.
         if not hasattr(options, "cmd"):
             print(
                 "* Only use this command if you know what you are doing! *\n"
                 "If not, use the 'gmg dbupdate' command instead.\n\n"
+                "(You can also pass --with-plugins here.)"
                 "Alembic help:\n")
             self.parser.print_help()
             return
@@ -45,6 +61,9 @@ class FudgedCommandLine(config.CommandLine):
             self.run_cmd(cfg, options)
         
 def parser_setup(subparser):
+    subparser.add_argument(
+        "--with-plugins", action="store_true",
+        help="Import all plugins' models before running alembic commands.")
     subparser.add_argument("args_for_alembic", nargs=argparse.REMAINDER)
 
 def raw_alembic_cli(args):