Support disabling apache wsgi socket rotation

Bug LP 1863232 introduced a new Apache configuration option called
WSGISocketRotation which allows users to disable wsgi socket
rotation. This patch makes this configurable with a new
wsgi-socket-rotation config option that defaults to the Apache
default and can optionally be set to False.

Change-Id: I34258c46c839db1c70a3967b7e1ee6889db8a7fd
Closes-Bug: #2021550

charmhelpers/contrib/openstack/context.py

@@ -1665,6 +1665,9 @@ class WSGIWorkerConfigContext(WorkerConfigContext):
 
     def __call__(self):
         total_processes = _calculate_workers()
+        enable_wsgi_socket_rotation = config('wsgi-socket-rotation')
+        if enable_wsgi_socket_rotation is None:
+            enable_wsgi_socket_rotation = True
         ctxt = {
             "service_name": self.service_name,
             "user": self.user,
@@ -1678,6 +1681,7 @@ class WSGIWorkerConfigContext(WorkerConfigContext):
             "public_processes": int(math.ceil(self.public_process_weight *
                                               total_processes)),
             "threads": 1,
+            "wsgi_socket_rotation": enable_wsgi_socket_rotation,
         }
         return ctxt
 

charmhelpers/contrib/openstack/templates/wsgi-openstack-api.conf

@@ -12,6 +12,12 @@ Listen {{ admin_port }}
 Listen {{ public_port }}
 {% endif -%}
 
+{% if wsgi_socket_rotation -%}
+WSGISocketRotation On
+{% else -%}
+WSGISocketRotation Off
+{% endif -%}
+
 {% if port -%}
 <VirtualHost *:{{ port }}>
     WSGIDaemonProcess {{ service_name }} processes={{ processes }} threads={{ threads }} user={{ user }} group={{ group }} \

charmhelpers/contrib/openstack/templates/wsgi-openstack-metadata.conf

@@ -12,6 +12,12 @@ Listen {{ admin_port }}
 Listen {{ public_port }}
 {% endif -%}
 
+{% if wsgi_socket_rotation -%}
+WSGISocketRotation On
+{% else -%}
+WSGISocketRotation Off
+{% endif -%}
+
 {% if port -%}
 <VirtualHost *:{{ port }}>
     WSGIDaemonProcess {{ service_name }} processes={{ processes }} threads={{ threads }} user={{ user }} group={{ group }} \

charmhelpers/fetch/snap.py

@@ -52,7 +52,7 @@ def _snap_exec(commands):
     :param commands: List commands
     :return: Integer exit code
     """
-    assert type(commands) == list
+    assert type(commands) is list
 
     retry_count = 0
     return_code = None

config.yaml

@@ -790,3 +790,11 @@ options:
       allowed and letting the request fail, Negative number: Allows
       unlimited number of local devices, Positive number: Allows only
       these many number of local devices.
+  wsgi-socket-rotation:
+    type: boolean
+    default: True
+    description: |
+      Allow users to disable Apache wsgi socket rotation. If not configured,
+      this option sets True as the default value, which is consistent with the
+      default value 'WSGISocketRotation On' in Apache. This option should be
+      used with caution. Please read the Apache doc page for more information.