add -e/--env command line argunment

This command line argunment allows someone to pass an environement variable to
gunicorn:

	$ gunicorn --env FOO=1 test:app

With the command line above the application will be able to use the FOO
environment vatriable.

examples/test.py

@@ -5,6 +5,7 @@
 #
 # Example code from Eventlet sources
 
+import os
 from wsgiref.validate import validator
 import sys
 
@@ -12,9 +13,12 @@ from gunicorn import __version__
 #@validator
 def app(environ, start_response):
     """Simplest possible application object"""
+
     data = b'Hello, World!\n'
     status = '200 OK'
 
+    print("foo=%s" % (os.environ['FOO']))
+
     response_headers = [
         ('Content-type','text/plain'),
         ('Content-Length', str(len(data))),

gunicorn/arbiter.py

@@ -122,6 +122,12 @@ class Arbiter(object):
             self.pidfile = Pidfile(self.cfg.pidfile)
             self.pidfile.create(self.pid)
         self.cfg.on_starting(self)
+
+        # set enviroment' variables
+        if self.cfg.env:
+            for k, v in self.cfg.env.items():
+                os.environ[k] = v
+
         self.init_signals()
         if not self.LISTENERS:
             self.LISTENERS = create_sockets(self.cfg, self.log)
@@ -346,17 +352,32 @@ class Arbiter(object):
             self.master_name = "Old Master"
             return
 
+        environ = self.cfg.env_orig.copy()
         fds = [l.fileno() for l in self.LISTENERS]
-        os.environ['GUNICORN_FD'] = ",".join([str(fd) for fd in fds])
+        environ['GUNICORN_FD'] = ",".join([str(fd) for fd in fds])
 
         os.chdir(self.START_CTX['cwd'])
         self.cfg.pre_exec(self)
 
-        os.execvpe(self.START_CTX[0], self.START_CTX['args'], os.environ)
+        # exec the process using the original environnement
+        os.execvpe(self.START_CTX[0], self.START_CTX['args'], environ)
 
     def reload(self):
         old_address = self.cfg.address
 
+        # reset old environement
+        for k in self.cfg.env:
+            if k in self.cfg.env_orig:
+                # reset the key to the value it had before
+                # we launched gunicorn
+                os.environ[k] = self.cfg.env_orig[k]
+            else:
+                # delete the value set by gunicorn
+                try:
+                    del os.environ[k]
+                except KeyError:
+                    pass
+
         # reload conf
         self.app.reload()
         self.setup(self.app)

gunicorn/config.py

@@ -48,8 +48,12 @@ class Config(object):
         self.settings = make_settings()
         self.usage = usage
         self.prog = prog or os.path.basename(sys.argv[0])
+        self.env_orig = os.environ.copy()
 
     def __getattr__(self, name):
+        if name == "env_orig":
+            return self.env_orig
+
         if name not in self.settings:
             raise AttributeError("No configuration setting for: %s" % name)
         return self.settings[name].get()
@@ -144,6 +148,23 @@ class Config(object):
 
         return opts
 
+    @property
+    def env(self):
+        env = {}
+        if not self.settings['raw_env']:
+            return env
+
+        for e in self.settings['raw_env'].get():
+            s = six.bytes_to_str(e)
+            try:
+                k, v = s.split('=')
+            except ValueError:
+                raise RuntimeError("environement setting %r invalid" % s)
+
+            env[k] = v
+
+        return env
+
 
 class SettingMeta(type):
     def __new__(cls, name, bases, attrs):
@@ -699,6 +720,23 @@ class Daemon(Setting):
         background.
         """
 
+class Env(Setting):
+    name = "raw_env"
+    action = "append"
+    section = "Server Mechanic"
+    cli = ["-e", "--env"]
+    meta = "ENV"
+    validator = validate_list_string
+
+    desc = """\
+        Set environment variable (key=value).
+
+        Pass variables to the execution environment. Ex.::
+
+            $ gunicorn -b 127.0.0.1:8000 --env FOO=1 test:app
+
+        and test for the foo variable environement in your application.
+        """
 
 class Pidfile(Setting):
     name = "pidfile"

gunicorn/workers/base.py

@@ -78,6 +78,12 @@ class Worker(object):
         super(MyWorkerClass, self).init_process() so that the ``run()``
         loop is initiated.
         """
+
+        # set enviroment' variables
+        if self.cfg.env:
+            for k, v in self.cfg.env.items():
+                os.environ[k] = v
+
         util.set_owner_process(self.cfg.uid, self.cfg.gid)
 
         # Reseed the random number generator