Specify wsgi_app in config #1359.

docs/source/run.rst

@@ -21,12 +21,15 @@ gunicorn
 
 Basic usage::
 
-    $ gunicorn [OPTIONS] APP_MODULE
+    $ gunicorn [OPTIONS] [WSGI_APP]
 
-Where ``APP_MODULE`` is of the pattern ``$(MODULE_NAME):$(VARIABLE_NAME)``. The
+Where ``WSGI_APP`` is of the pattern ``$(MODULE_NAME):$(VARIABLE_NAME)``. The
 module name can be a full dotted path. The variable name refers to a WSGI
 callable that should be found in the specified module.
 
+.. versionchanged:: 20.1.0
+    ``WSGI_APP`` is optional if it is defined in a :ref:`config` file.
+
 Example with the test app:
 
 .. code-block:: python

docs/source/settings.rst

@@ -42,6 +42,17 @@ application specific configuration.
    Loading the config from a Python module requires the ``python:``
    prefix.
 
+.. _wsgi-app:
+
+wsgi_app
+~~~~~~~~
+
+* ``None``
+
+A WSGI application path in pattern ``$(MODULE_NAME):$(VARIABLE_NAME)``.
+
+.. versionadded:: 20.1.0
+
 Debugging
 ---------
 

gunicorn/app/wsgiapp.py

@@ -12,6 +12,8 @@ from gunicorn import util
 
 class WSGIApplication(Application):
     def init(self, parser, opts, args):
+        self.app_uri = None
+
         if opts.paste:
             from .pasterapp import has_logging_config
 
@@ -29,11 +31,18 @@ class WSGIApplication(Application):
 
             return
 
-        if not args:
+        if len(args) > 0:
-            parser.error("No application module specified.")
+            self.cfg.set("default_proc_name", args[0])
+            self.app_uri = args[0]
 
-        self.cfg.set("default_proc_name", args[0])
+    def load_config(self):
-        self.app_uri = args[0]
+        super().load_config()
+
+        if self.app_uri is None:
+            if self.cfg.wsgi_app is not None:
+                self.app_uri = self.cfg.wsgi_app
+            else:
+                raise ConfigError("No application module specified.")
 
     def load_wsgiapp(self):
         return util.import_app(self.app_uri)

gunicorn/config.py

@@ -560,6 +560,17 @@ class ConfigFile(Setting):
            prefix.
         """
 
+class WSGIApp(Setting):
+    name = "wsgi_app"
+    section = "Config File"
+    meta = "STRING"
+    validator = validate_string
+    default = None
+    desc = """\
+        A WSGI application path in pattern ``$(MODULE_NAME):$(VARIABLE_NAME)``.
+
+        .. versionadded:: 20.1.0
+        """
 
 class Bind(Setting):
     name = "bind"

tests/config/test_cfg_with_wsgi_app.py

@@ -0,0 +1 @@
+wsgi_app = "app1:app1"

tests/test_config.py

@@ -11,6 +11,7 @@ import pytest
 
 from gunicorn import config
 from gunicorn.app.base import Application
+from gunicorn.app.wsgiapp import WSGIApplication
 from gunicorn.errors import ConfigError
 from gunicorn.workers.sync import SyncWorker
 from gunicorn import glogging
@@ -25,6 +26,8 @@ def cfg_file():
     return os.path.join(dirname, "config", "test_cfg.py")
 def alt_cfg_file():
     return os.path.join(dirname, "config", "test_cfg_alt.py")
+def cfg_file_with_wsgi_app():
+    return os.path.join(dirname, "config", "test_cfg_with_wsgi_app.py")
 def paster_ini():
     return os.path.join(dirname, "..", "examples", "frameworks", "pylonstest", "nose.ini")
 
@@ -52,6 +55,14 @@ class NoConfigApp(Application):
         pass
 
 
+class WSGIApp(WSGIApplication):
+    def __init__(self):
+        super().__init__("no_usage", prog="gunicorn_test")
+
+    def load(self):
+        pass
+
+
 def test_defaults():
     c = config.Config()
     for s in config.KNOWN_SETTINGS:
@@ -353,6 +364,7 @@ def test_invalid_enviroment_variables_config(monkeypatch, capsys):
         _, err = capsys.readouterr()
         assert  "error: unrecognized arguments: --foo" in err
 
+
 def test_cli_overrides_enviroment_variables_module(monkeypatch):
     monkeypatch.setenv("GUNICORN_CMD_ARGS", "--workers=4")
     with AltArgs(["prog_name", "-c", cfg_file(), "--workers", "3"]):
@@ -360,6 +372,34 @@ def test_cli_overrides_enviroment_variables_module(monkeypatch):
     assert app.cfg.workers == 3
 
 
+@pytest.mark.parametrize("options, expected", [
+    (["app:app"], 'app:app'),
+    (["-c", cfg_file(), "app:app"], 'app:app'),
+    (["-c", cfg_file_with_wsgi_app(), "app:app"], 'app:app'),
+    (["-c", cfg_file_with_wsgi_app()], 'app1:app1'),
+])
+def test_wsgi_app_config(options, expected):
+    cmdline = ["prog_name"]
+    cmdline.extend(options)
+    with AltArgs(cmdline):
+        app = WSGIApp()
+    assert app.app_uri == expected
+
+
+@pytest.mark.parametrize("options", [
+    ([]),
+    (["-c", cfg_file()]),
+])
+def test_non_wsgi_app(options, capsys):
+    cmdline = ["prog_name"]
+    cmdline.extend(options)
+    with AltArgs(cmdline):
+        with pytest.raises(SystemExit):
+            WSGIApp()
+        _, err = capsys.readouterr()
+        assert  "Error: No application module specified." in err
+
+
 @pytest.mark.parametrize("options, expected", [
     (["myapp:app"], False),
     (["--reload", "myapp:app"], True),