Add --factory option (#351)

granian/_internal.py

@@ -50,7 +50,7 @@ def load_module(module_name: str, raise_on_failure: bool = True) -> Optional[Mod
     return sys.modules[module_name]
 
 
-def load_target(target: str) -> Callable[..., None]:
+def load_target(target: str, factory: bool = False) -> Callable[..., None]:
     sys.path.insert(0, '')
     path, name = get_import_components(target)
     path = prepare_import(path) if path else None
@@ -59,4 +59,6 @@ def load_target(target: str) -> Callable[..., None]:
     rv = module
     for element in name.split('.'):
         rv = getattr(rv, element)
+    if factory:
+        rv = rv()
     return rv

granian/cli.py

@@ -195,6 +195,11 @@ def option(*param_decls: str, cls: Optional[Type[click.Option]] = None, **attrs:
     type=click.IntRange(60),
     help='The maximum amount of time in seconds a worker will be kept alive before respawn',
 )
+@option(
+    '--factory/--no-factory',
+    default=False,
+    help='Treat target as a factory function, that should be invoked to build the actual target',
+)
 @option(
     '--reload/--no-reload',
     default=False,
@@ -278,6 +283,7 @@ def cli(
     respawn_failed_workers: bool,
     respawn_interval: float,
     workers_lifetime: Optional[int],
+    factory: bool,
     reload: bool,
     reload_paths: Optional[List[pathlib.Path]],
     reload_ignore_dirs: Optional[List[str]],
@@ -336,6 +342,7 @@ def cli(
         respawn_failed_workers=respawn_failed_workers,
         respawn_interval=respawn_interval,
         workers_lifetime=workers_lifetime,
+        factory=factory,
         reload=reload,
         reload_paths=reload_paths,
         reload_ignore_paths=reload_ignore_paths,

granian/server.py

@@ -97,6 +97,7 @@ def __init__(
         respawn_failed_workers: bool = False,
         respawn_interval: float = 3.5,
         workers_lifetime: Optional[int] = None,
+        factory: bool = False,
         reload: bool = False,
         reload_paths: Optional[Sequence[Path]] = None,
         reload_ignore_dirs: Optional[Sequence[str]] = None,
@@ -138,6 +139,7 @@ def __init__(
         self.reload_on_changes = reload
         self.respawn_interval = respawn_interval
         self.workers_lifetime = workers_lifetime
+        self.factory = factory
         self.reload_paths = reload_paths or [Path.cwd()]
         self.reload_ignore_paths = reload_ignore_paths or ()
         self.reload_ignore_dirs = reload_ignore_dirs or ()
@@ -680,7 +682,7 @@ def serve(
             if wrap_loader:
                 target_loader = partial(target_loader, self.target)
         else:
-            target_loader = partial(load_target, self.target)
+            target_loader = partial(load_target, self.target, factory=self.factory)
 
         if not spawn_target:
             spawn_target = default_spawners[self.interface]