Merge pull request #727 from benoitc/feature/651

PR that rebase #651. Should also fix #625.

Add the capability to load gunicorn.base.Application without the
loading of the arguments of the command line.

docs/source/custom.rst

@@ -0,0 +1,61 @@
+.. _custom:
+
+==================
+Custom Application
+==================
+
+.. versionadded:: 19.0
+
+Sometimes, you want to integrate Gunicorn with your WSGI application. In this
+case, you can inherit from :class:`gunicorn.app.base.BaseApplication`.
+
+Here is a small example where we create a very small WSGI app and load it with a
+custom Application::
+
+    #!/usr/bin/env python
+    import gunicorn.app.base
+
+    def handler_app(environ, start_response):
+        response_body = 'Works fine'
+        status = '200 OK'
+
+        response_headers = [
+            ('Content-Type', 'text/plain'),
+            ('Content-Length', str(len(response_body)))
+        ]
+
+        start_response(status, response_headers)
+
+        return [response_body]
+
+    class StandaloneApplication(gunicorn.app.base.BaseApplication):
+        def __init__(self, app, options=None):
+            self.options = dict(options or {})
+            self.application = app
+            super(StandaloneApplication, self).__init__()
+
+        def load_config(self):
+            tmp_config = map(
+                lambda item: (item[0].lower(), item[1]),
+                self.options.iteritems()
+            )
+
+            config = dict(
+                (key, value)
+                for key, value in tmp_config
+                if key in self.cfg.settings and value is not None
+            )
+
+            for key, value in config.iteritems():
+                self.cfg.set(key.lower(), value)
+
+        def load(self):
+            return self.application
+
+    if __name__ == '__main__':
+        options = {
+            'bind': '%s:%s' % ('127.0.0.1', '8080'),
+            'workers': 4,
+            # 'pidfile': pidfile,
+        }
+        StandaloneApplication(handler_app, options).run()

docs/source/index.rst

@@ -43,6 +43,7 @@ Contents
     deploy
     design
     signals
+    custom
     community
     faq
     news

examples/standalone_app.py

@@ -0,0 +1,63 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+#
+# An example of a standalone application using the internal API of Gunicorn.
+#
+#   $ python standalone_app.py
+#
+# This file is part of gunicorn released under the MIT license.
+# See the NOTICE for more information.
+
+import gunicorn
+import gunicorn.app.base
+import multiprocessing
+
+def number_of_workers():
+    return (multiprocessing.cpu_count() * 2) + 1
+
+
+def handler_app(environ, start_response):
+    response_body = 'Works fine'
+    status = '200 OK'
+
+    response_headers = [
+        ('Content-Type', 'text/plain'),
+        ('Content-Lenfth', str(len(response_body))),
+    ]
+
+    start_response(status, response_headers)
+
+    return [response_body]
+
+
+class StandaloneApplication(gunicorn.app.base.BaseApplication):
+    def __init__(self, app, options=None):
+        self.options = dict(options or {})
+        self.application = app
+        super(StandaloneApplication, self).__init__()
+
+    def load_config(self):
+        tmp_config = map(
+            lambda item: (item[0].lower(), item[1]),
+            self.options.iteritems()
+        )
+
+        config = dict(
+            (key, value)
+            for key, value in tmp_config
+            if key in self.cfg.settings and value is not None
+        )
+
+        for key, value in config.iteritems():
+            self.cfg.set(key.lower(), value)
+
+    def load(self):
+        return self.application
+
+
+if __name__ == '__main__':
+    options = {
+        'bind': '%s:%s' % ('127.0.0.1', '8080'),
+        'workers': number_of_workers(),
+    }
+    StandaloneApplication(handler_app, options).run()

gunicorn/app/base.py

@@ -13,12 +13,11 @@ from gunicorn.config import Config, get_default_config_file
 from gunicorn import debug
 from gunicorn.six import execfile_
 
-class Application(object):
-    """\
+class BaseApplication(object):
+    """
     An application interface for configuring and loading
     the various necessities for any given web framework.
     """
-
     def __init__(self, usage=None, prog=None):
         self.usage = usage
         self.cfg = None
@@ -28,15 +27,59 @@ class Application(object):
         self.do_load_config()
 
     def do_load_config(self):
+        """
+        Loads the configuration
+        """
         try:
+            self.load_default_config()
             self.load_config()
         except Exception as e:
             sys.stderr.write("\nError: %s\n" % str(e))
             sys.stderr.flush()
             sys.exit(1)
 
-    def load_config_from_file(self, filename):
+    def load_default_config(self):
+        # init configuration
+        self.cfg = Config(self.usage, prog=self.prog)
 
+    def init(self, parser, opts, args):
+        raise NotImplementedError
+
+    def load(self):
+        raise NotImplementedError
+
+    def load_config(self):
+        """
+        This method is used to load the configuration from one or several input(s).
+        Custom Command line, configuration file.
+        You have to override this method in your class.
+        """
+        raise NotImplementedError
+
+    def reload(self):
+        self.do_load_config()
+        if self.cfg.spew:
+            debug.spew()
+
+    def wsgi(self):
+        if self.callable is None:
+            self.callable = self.load()
+        return self.callable
+
+    def run(self):
+        try:
+            Arbiter(self).run()
+        except RuntimeError as e:
+            sys.stderr.write("\nError: %s\n\n" % e)
+            sys.stderr.flush()
+            sys.exit(1)
+
+class Application(BaseApplication):
+    def load_config_from_file(self, filename):
+        """
+        Loads the configuration file: the file is a python file, otherwise raise an RuntimeError
+        Exception or stop the process if the configuration file contains a syntax error.
+        """
         if not os.path.exists(filename):
             raise RuntimeError("%r doesn't exist" % filename)
 
@@ -67,9 +110,6 @@ class Application(object):
         return cfg
 
     def load_config(self):
-        # init configuration
-        self.cfg = Config(self.usage, prog=self.prog)
-
         # parse console args
         parser = self.cfg.parser()
         args = parser.parse_args()
@@ -98,22 +138,6 @@ class Application(object):
                 continue
             self.cfg.set(k.lower(), v)
 
-    def init(self, parser, opts, args):
-        raise NotImplementedError
-
-    def load(self):
-        raise NotImplementedError
-
-    def reload(self):
-        self.do_load_config()
-        if self.cfg.spew:
-            debug.spew()
-
-    def wsgi(self):
-        if self.callable is None:
-            self.callable = self.load()
-        return self.callable
-
     def run(self):
         if self.cfg.check_config:
             try:
@@ -139,9 +163,4 @@ class Application(object):
                 if pythonpath not in sys.path:
                     sys.path.insert(0, pythonpath)
 
-        try:
-            Arbiter(self).run()
-        except RuntimeError as e:
-            sys.stderr.write("\nError: %s\n\n" % e)
-            sys.stderr.flush()
-            sys.exit(1)
+        super(Application, self).run()