Add framework for a site status banner.

- still needs style
- will cache for 10 seconds

common/djangoapps/status/__init__.py

+

common/djangoapps/status/status.py

+"""
+A tiny app that checks for a status message.
+"""
+
+from django.conf import settings
+import logging
+import os
+import sys
+
+from util.cache import cache
+
+log = logging.getLogger(__name__)
+
+def get_site_status_msg():
+    """
+    Look for a file settings.STATUS_MESSAGE_PATH.  If found, return the
+    contents.  Otherwise, return None.  Caches result for 10 seconds, per-machine.
+
+    If something goes wrong, returns None.  ("is there a status msg?" logic is
+    not allowed to break the entire site).
+    """
+    cache_time = 10
+    try:
+        key = ','.join([settings.HOSTNAME, settings.STATUS_MESSAGE_PATH])
+        content = cache.get(key)
+        if content == '':
+            # cached that there isn't a status message
+            return None
+
+        if content is None:
+            # nothing in the cache, so check the filesystem
+            if os.path.isfile(settings.STATUS_MESSAGE_PATH):
+                with open(settings.STATUS_MESSAGE_PATH) as f:
+                    content = f.read()
+            else:
+                # remember that there isn't anything there
+                cache.set(key, '', cache_time)
+                content = None
+
+        return content
+    except:
+        log.debug("Error while getting a status message: {0}".format(sys.exc_info()))
+        return None

lms/envs/common.py

@@ -25,6 +25,7 @@ import glob2
 import errno
 import hashlib
 from collections import defaultdict
+import socket
 
 import djcelery
 from path import path
@@ -95,6 +96,13 @@ GENERATE_PROFILE_SCORES = False
 # Used with XQueue
 XQUEUE_WAITTIME_BETWEEN_REQUESTS = 5 # seconds
 
+
+# Used for per-maching caching
+try:
+    HOSTNAME = socket.gethostname()
+except:
+    HOSTNAME = 'localhost'
+
 ############################# SET PATH INFORMATION #############################
 PROJECT_ROOT = path(__file__).abspath().dirname().dirname()  # /mitx/lms
 REPO_ROOT = PROJECT_ROOT.dirname()
@@ -103,7 +111,6 @@ ENV_ROOT = REPO_ROOT.dirname()  # virtualenv dir /mitx is in
 ASKBOT_ROOT = REPO_ROOT / "askbot"
 COURSES_ROOT = ENV_ROOT / "data"
 
-# FIXME: To support multiple courses, we should walk the courses dir at startup
 DATA_DIR = COURSES_ROOT
 
 sys.path.append(REPO_ROOT)
@@ -127,6 +134,9 @@ node_paths = [COMMON_ROOT / "static/js/vendor",
 NODE_PATH = ':'.join(node_paths)
 
 
+# Where to look for a status message
+STATUS_MESSAGE_PATH = ENV_ROOT / "status_message.html"
+
 ############################ OpenID Provider  ##################################
 OPENID_PROVIDER_TRUSTED_ROOTS = ['cs50.net', '*.cs50.net']
 

lms/templates/navigation.html

@@ -8,19 +8,27 @@ from django.core.urlresolvers import reverse
 
 # App that handles subdomain specific branding
 import branding
+# app that handles site status messages
+from status.status import get_site_status_msg
+site_status_msg = get_site_status_msg()
 %>
 
-%if course:
+% if site_status_msg:
+<div class="site-status">${site_status_msg}</div>
+% endif
+  
+
+% if course:
   <header class="global slim" aria-label="Global Navigation">
-%else:
+% else:
   <header class="global" aria-label="Global Navigation">
-%endif
+% endif
   <nav>
   <h1 class="logo"><a href="${reverse('root')}"><img src="${static.url(branding.get_logo_url(request.META.get('HTTP_HOST')))}"/></a></h1>
 
-    %if course:
+    % if course:
       <h2><span class="provider">${course.org}:</span> ${course.number} ${course.title}</h2>
-    %endif
+    % endif
 
     <ol class="left find-courses-button">
       <li class="primary">
@@ -28,7 +36,7 @@ import branding
       </li>
     </ol>
 
-  %if user.is_authenticated():
+  % if user.is_authenticated():
     <ol class="user">
       <li class="primary">
         <a href="${reverse('dashboard')}" class="user-link">
@@ -46,7 +54,7 @@ import branding
       </li>
     </ol>
 
-  %else:
+  % else:
     <ol class="guest">
       <li class="secondary">
         <a href="${reverse('about_edx')}">About</a>