Merge pull request #2063 from edx/feature/rocha/lets-use-celery

Add Celery configuration to LMS and CMS 

cms/envs/aws.py

@@ -28,6 +28,47 @@ EMAIL_BACKEND = 'django_ses.SESBackend'
 SESSION_ENGINE = 'django.contrib.sessions.backends.cache'
 DEFAULT_FILE_STORAGE = 'storages.backends.s3boto.S3BotoStorage'
 
+###################################### CELERY  ################################
+
+# Don't use a connection pool, since connections are dropped by ELB.
+BROKER_POOL_LIMIT = 0
+BROKER_CONNECTION_TIMEOUT = 1
+
+# For the Result Store, use the django cache named 'celery'
+CELERY_RESULT_BACKEND = 'cache'
+CELERY_CACHE_BACKEND = 'celery'
+
+# When the broker is behind an ELB, use a heartbeat to refresh the
+# connection and to detect if it has been dropped.
+BROKER_HEARTBEAT = 10.0
+BROKER_HEARTBEAT_CHECKRATE = 2
+
+# Each worker should only fetch one message at a time
+CELERYD_PREFETCH_MULTIPLIER = 1
+
+# Skip djcelery migrations, since we don't use the database as the broker
+SOUTH_MIGRATION_MODULES = {
+    'djcelery': 'ignore',
+}
+
+# Rename the exchange and queues for each variant
+
+QUEUE_VARIANT = CONFIG_PREFIX.lower()
+
+CELERY_DEFAULT_EXCHANGE = 'edx.{0}core'.format(QUEUE_VARIANT)
+
+HIGH_PRIORITY_QUEUE = 'edx.{0}core.high'.format(QUEUE_VARIANT)
+DEFAULT_PRIORITY_QUEUE = 'edx.{0}core.default'.format(QUEUE_VARIANT)
+LOW_PRIORITY_QUEUE = 'edx.{0}core.low'.format(QUEUE_VARIANT)
+
+CELERY_DEFAULT_ROUTING_KEY = DEFAULT_PRIORITY_QUEUE
+
+CELERY_QUEUES = {
+    HIGH_PRIORITY_QUEUE: {},
+    LOW_PRIORITY_QUEUE: {},
+    DEFAULT_PRIORITY_QUEUE: {}
+}
+
 ############# NON-SECURE ENV CONFIG ##############################
 # Things like server locations, ports, etc.
 with open(ENV_ROOT / CONFIG_PREFIX + "env.json") as env_file:
@@ -78,3 +119,14 @@ CONTENTSTORE = AUTH_TOKENS['CONTENTSTORE']
 
 # Datadog for events!
 DATADOG_API = AUTH_TOKENS.get("DATADOG_API")
+
+# Celery Broker
+CELERY_BROKER_TRANSPORT = ENV_TOKENS.get("CELERY_BROKER_TRANSPORT", "")
+CELERY_BROKER_HOSTNAME = ENV_TOKENS.get("CELERY_BROKER_HOSTNAME", "")
+CELERY_BROKER_USER = AUTH_TOKENS.get("CELERY_BROKER_USER", "")
+CELERY_BROKER_PASSWORD = AUTH_TOKENS.get("CELERY_BROKER_PASSWORD", "")
+
+BROKER_URL = "{0}://{1}:{2}@{3}".format(CELERY_BROKER_TRANSPORT,
+                                        CELERY_BROKER_USER,
+                                        CELERY_BROKER_PASSWORD,
+                                        CELERY_BROKER_HOSTNAME)

cms/envs/common.py

@@ -34,6 +34,9 @@ MITX_FEATURES = {
     'STAFF_EMAIL': '',			# email address for staff (eg to request course creation)
     'STUDIO_NPS_SURVEY': True,
     'SEGMENT_IO': True,
+
+    # Enable URL that shows information about the status of variuous services
+    'ENABLE_SERVICE_STATUS': False,
 }
 ENABLE_JASMINE = False
 
@@ -240,6 +243,51 @@ STATICFILES_IGNORE_PATTERNS = (
 
 PIPELINE_YUI_BINARY = 'yui-compressor'
 
+################################# CELERY ######################################
+
+# Message configuration
+
+CELERY_TASK_SERIALIZER = 'json'
+CELERY_RESULT_SERIALIZER = 'json'
+
+CELERY_MESSAGE_COMPRESSION = 'gzip'
+
+# Results configuration
+
+CELERY_IGNORE_RESULT = False
+CELERY_STORE_ERRORS_EVEN_IF_IGNORED = True
+
+# Events configuration
+
+CELERY_TRACK_STARTED = True
+
+CELERY_SEND_EVENTS = True
+CELERY_SEND_TASK_SENT_EVENT = True
+
+# Exchange configuration
+
+CELERY_DEFAULT_EXCHANGE = 'edx.core'
+CELERY_DEFAULT_EXCHANGE_TYPE = 'direct'
+
+# Queues configuration
+
+HIGH_PRIORITY_QUEUE = 'edx.core.high'
+DEFAULT_PRIORITY_QUEUE = 'edx.core.default'
+LOW_PRIORITY_QUEUE = 'edx.core.low'
+
+CELERY_QUEUE_HA_POLICY = 'all'
+
+CELERY_CREATE_MISSING_QUEUES = True
+
+CELERY_DEFAULT_QUEUE = DEFAULT_PRIORITY_QUEUE
+CELERY_DEFAULT_ROUTING_KEY = DEFAULT_PRIORITY_QUEUE
+
+CELERY_QUEUES = {
+    HIGH_PRIORITY_QUEUE: {},
+    LOW_PRIORITY_QUEUE: {},
+    DEFAULT_PRIORITY_QUEUE: {}
+}
+
 ############################ APPS #####################################
 
 INSTALLED_APPS = (
@@ -249,8 +297,12 @@ INSTALLED_APPS = (
     'django.contrib.sessions',
     'django.contrib.sites',
     'django.contrib.messages',
+    'djcelery',
     'south',
 
+    # Monitor the status of services
+    'service_status',
+
     # For CMS
     'contentstore',
     'auth',

cms/envs/dev.py

@@ -116,6 +116,11 @@ SECRET_KEY = '85920908f28904ed733fe576320db18cabd7b6cd'
 
 PIPELINE_SASS_ARGUMENTS = '--debug-info --require {proj_dir}/static/sass/bourbon/lib/bourbon.rb'.format(proj_dir=PROJECT_ROOT)
 
+################################# CELERY ######################################
+
+# By default don't use a worker, execute tasks as if they were local functions
+CELERY_ALWAYS_EAGER = True
+
 ################################ DEBUG TOOLBAR #################################
 INSTALLED_APPS += ('debug_toolbar', 'debug_toolbar_mongo')
 MIDDLEWARE_CLASSES += ('django_comment_client.utils.QueryCountDebugMiddleware',
@@ -151,5 +156,8 @@ DEBUG_TOOLBAR_MONGO_STACKTRACES = True
 # disable NPS survey in dev mode
 MITX_FEATURES['STUDIO_NPS_SURVEY'] = False
 
+# Enable URL that shows information about the status of variuous services
+MITX_FEATURES['ENABLE_SERVICE_STATUS'] = True
+
 # segment-io key for dev
 SEGMENT_IO_KEY = 'mty8edrrsg'

cms/envs/dev_with_worker.py

+"""
+This config file follows the dev enviroment, but adds the
+requirement of a celery worker running in the background to process
+celery tasks.
+
+The worker can be executed using:
+
+django_admin.py celery worker
+"""
+
+from dev import *
+
+################################# CELERY ######################################
+
+# Requires a separate celery worker
+
+CELERY_ALWAYS_EAGER = False
+
+# Use django db as the broker and result store
+
+BROKER_URL = 'django://'
+INSTALLED_APPS += ('djcelery.transport', )
+CELERY_RESULT_BACKEND = 'database'
+DJKOMBU_POLLING_INTERVAL = 1.0
+
+# Disable transaction management because we are using a worker. Views
+# that request a task and wait for the result will deadlock otherwise.
+
+MIDDLEWARE_CLASSES = tuple(
+    c for c in MIDDLEWARE_CLASSES
+    if c != 'django.middleware.transaction.TransactionMiddleware')
+
+# Note: other alternatives for disabling transactions don't work in 1.4
+# https://code.djangoproject.com/ticket/2304
+# https://code.djangoproject.com/ticket/16039

cms/envs/test.py

@@ -108,6 +108,12 @@ CACHES = {
     }
 }
 
+################################# CELERY ######################################
+
+CELERY_ALWAYS_EAGER = True
+CELERY_RESULT_BACKEND = 'cache'
+BROKER_TRANSPORT = 'memory'
+
 ################### Make tests faster
 #http://slacy.com/blog/2012/04/make-your-tests-faster-in-django-1-4/
 PASSWORD_HASHERS = (
@@ -121,3 +127,4 @@ SEGMENT_IO_KEY = '***REMOVED***'
 # disable NPS survey in test mode
 MITX_FEATURES['STUDIO_NPS_SURVEY'] = False
 
+MITX_FEATURES['ENABLE_SERVICE_STATUS'] = True

cms/urls.py

@@ -135,6 +135,12 @@ if settings.ENABLE_JASMINE:
     # # Jasmine
     urlpatterns = urlpatterns + (url(r'^_jasmine/', include('django_jasmine.urls')),)
 
+
+if settings.MITX_FEATURES.get('ENABLE_SERVICE_STATUS'):
+    urlpatterns += (
+        url(r'^status/', include('service_status.urls')),
+    )
+
 urlpatterns = patterns(*urlpatterns)
 
 # Custom error pages

common/djangoapps/service_status/__init__.py

+"""
+Stub for a Django app to report the status of various services
+"""

common/djangoapps/service_status/tasks.py

+"""
+Django Celery tasks for service status app
+"""
+
+import time
+
+from dogapi import dog_stats_api
+
+from djcelery import celery
+
+
+@celery.task
+@dog_stats_api.timed('status.service.celery.pong')
+def delayed_ping(value, delay):
+    """A simple tasks that replies to a message after a especified amount
+    of seconds.
+    """
+    if value == 'ping':
+        result = 'pong'
+    else:
+        result = 'got: {0}'.format(value)
+
+    time.sleep(delay)
+
+    return result

common/djangoapps/service_status/test.py

+"""Test for async task service status"""
+
+from django.utils import unittest
+from django.test.client import Client
+from django.core.urlresolvers import reverse
+import json
+
+
+class CeleryConfigTest(unittest.TestCase):
+    """
+    Test that we can get a response from Celery
+    """
+
+    def setUp(self):
+        """
+        Create a django test client
+        """
+        self.client = Client()
+        self.ping_url = reverse('status.service.celery.ping')
+
+    def test_ping(self):
+        """
+        Try to ping celery.
+        """
+
+        # Access the service status page, which starts a delayed
+        # asynchronous task
+        response = self.client.get(self.ping_url)
+
+        # HTTP response should be successful
+        self.assertEqual(response.status_code, 200)
+
+        # Expect to get a JSON-serialized dict with
+        # task and time information
+        result_dict = json.loads(response.content)
+
+        # Was it successful?
+        self.assertTrue(result_dict['success'])
+
+        # We should get a "pong" message back
+        self.assertEqual(result_dict['value'], "pong")
+
+        # We don't know the other dict values exactly,
+        # but we can assert that they take the right form
+        self.assertTrue(isinstance(result_dict['task_id'], unicode))
+        self.assertTrue(isinstance(result_dict['time'], float))
+        self.assertTrue(result_dict['time'] > 0.0)

common/djangoapps/service_status/urls.py

+"""
+Django URLs for service status app
+"""
+
+from django.conf.urls import patterns, url
+
+
+urlpatterns = patterns(
+    '',
+    url(r'^$', 'service_status.views.index', name='status.service.index'),
+    url(r'^celery/$', 'service_status.views.celery_status',
+        name='status.service.celery.status'),
+    url(r'^celery/ping/$', 'service_status.views.celery_ping',
+        name='status.service.celery.ping'),
+)

common/djangoapps/service_status/views.py

+"""
+Django Views for service status app
+"""
+
+import json
+import time
+
+from django.http import HttpResponse
+
+from dogapi import dog_stats_api
+
+from service_status import tasks
+from djcelery import celery
+from celery.exceptions import TimeoutError
+
+
+def index(_):
+    """
+    An empty view
+    """
+    return HttpResponse()
+
+
+@dog_stats_api.timed('status.service.celery.status')
+def celery_status(_):
+    """
+    A view that returns Celery stats
+    """
+    stats = celery.control.inspect().stats() or {}
+    return HttpResponse(json.dumps(stats, indent=4),
+                        mimetype="application/json")
+
+
+@dog_stats_api.timed('status.service.celery.ping')
+def celery_ping(_):
+    """
+    A Simple view that checks if Celery can process a simple task
+    """
+    start = time.time()
+    result = tasks.delayed_ping.apply_async(('ping', 0.1))
+    task_id = result.id
+
+    # Wait until we get the result
+    try:
+        value = result.get(timeout=4.0)
+        success = True
+    except TimeoutError:
+        value = None
+        success = False
+
+    output = {
+        'success': success,
+        'task_id': task_id,
+        'value': value,
+        'time': time.time() - start,
+    }
+
+    return HttpResponse(json.dumps(output, indent=4),
+                        mimetype="application/json")

lms/envs/aws.py

@@ -26,7 +26,8 @@ if SERVICE_VARIANT:
     CONFIG_PREFIX = SERVICE_VARIANT + "."
 
 
-################### ALWAYS THE SAME ################################
+################################ ALWAYS THE SAME ##############################
+
 DEBUG = False
 TEMPLATE_DEBUG = False
 
@@ -45,7 +46,48 @@ MITX_FEATURES['ENABLE_DISCUSSION_SERVICE'] = True
 # for other warnings.
 SECURE_PROXY_SSL_HEADER = ('HTTP_X_FORWARDED_PROTO', 'https')
 
-################# NON-SECURE ENV CONFIG ##############################
+###################################### CELERY  ################################
+
+# Don't use a connection pool, since connections are dropped by ELB.
+BROKER_POOL_LIMIT = 0
+BROKER_CONNECTION_TIMEOUT = 1
+
+# For the Result Store, use the django cache named 'celery'
+CELERY_RESULT_BACKEND = 'cache'
+CELERY_CACHE_BACKEND = 'celery'
+
+# When the broker is behind an ELB, use a heartbeat to refresh the
+# connection and to detect if it has been dropped.
+BROKER_HEARTBEAT = 10.0
+BROKER_HEARTBEAT_CHECKRATE = 2
+
+# Each worker should only fetch one message at a time
+CELERYD_PREFETCH_MULTIPLIER = 1
+
+# Skip djcelery migrations, since we don't use the database as the broker
+SOUTH_MIGRATION_MODULES = {
+    'djcelery': 'ignore',
+}
+
+# Rename the exchange and queues for each variant
+
+QUEUE_VARIANT = CONFIG_PREFIX.lower()
+
+CELERY_DEFAULT_EXCHANGE = 'edx.{0}core'.format(QUEUE_VARIANT)
+
+HIGH_PRIORITY_QUEUE = 'edx.{0}core.high'.format(QUEUE_VARIANT)
+DEFAULT_PRIORITY_QUEUE = 'edx.{0}core.default'.format(QUEUE_VARIANT)
+LOW_PRIORITY_QUEUE = 'edx.{0}core.low'.format(QUEUE_VARIANT)
+
+CELERY_DEFAULT_ROUTING_KEY = DEFAULT_PRIORITY_QUEUE
+
+CELERY_QUEUES = {
+    HIGH_PRIORITY_QUEUE: {},
+    LOW_PRIORITY_QUEUE: {},
+    DEFAULT_PRIORITY_QUEUE: {}
+}
+
+########################## NON-SECURE ENV CONFIG ##############################
 # Things like server locations, ports, etc.
 
 with open(ENV_ROOT / CONFIG_PREFIX + "env.json") as env_file:
@@ -104,6 +146,7 @@ COURSES_WITH_UNSAFE_CODE = ENV_TOKENS.get("COURSES_WITH_UNSAFE_CODE", [])
 
 ############################## SECURE AUTH ITEMS ###############
 # Secret things: passwords, access keys, etc.
+
 with open(ENV_ROOT / CONFIG_PREFIX + "auth.json") as auth_file:
     AUTH_TOKENS = json.load(auth_file)
 
@@ -122,7 +165,8 @@ XQUEUE_INTERFACE = AUTH_TOKENS['XQUEUE_INTERFACE']
 MODULESTORE = AUTH_TOKENS.get('MODULESTORE', MODULESTORE)
 CONTENTSTORE = AUTH_TOKENS.get('CONTENTSTORE', CONTENTSTORE)
 
-OPEN_ENDED_GRADING_INTERFACE = AUTH_TOKENS.get('OPEN_ENDED_GRADING_INTERFACE', OPEN_ENDED_GRADING_INTERFACE)
+OPEN_ENDED_GRADING_INTERFACE = AUTH_TOKENS.get('OPEN_ENDED_GRADING_INTERFACE',
+                                               OPEN_ENDED_GRADING_INTERFACE)
 
 PEARSON_TEST_USER = "pearsontest"
 PEARSON_TEST_PASSWORD = AUTH_TOKENS.get("PEARSON_TEST_PASSWORD")
@@ -137,5 +181,17 @@ DATADOG_API = AUTH_TOKENS.get("DATADOG_API")
 ANALYTICS_SERVER_URL = ENV_TOKENS.get("ANALYTICS_SERVER_URL")
 ANALYTICS_API_KEY = AUTH_TOKENS.get("ANALYTICS_API_KEY", "")
 
+# Zendesk
 ZENDESK_USER = AUTH_TOKENS.get("ZENDESK_USER")
 ZENDESK_API_KEY = AUTH_TOKENS.get("ZENDESK_API_KEY")
+
+# Celery Broker
+CELERY_BROKER_TRANSPORT = ENV_TOKENS.get("CELERY_BROKER_TRANSPORT", "")
+CELERY_BROKER_HOSTNAME = ENV_TOKENS.get("CELERY_BROKER_HOSTNAME", "")
+CELERY_BROKER_USER = AUTH_TOKENS.get("CELERY_BROKER_USER", "")
+CELERY_BROKER_PASSWORD = AUTH_TOKENS.get("CELERY_BROKER_PASSWORD", "")
+
+BROKER_URL = "{0}://{1}:{2}@{3}".format(CELERY_BROKER_TRANSPORT,
+                                        CELERY_BROKER_USER,
+                                        CELERY_BROKER_PASSWORD,
+                                        CELERY_BROKER_HOSTNAME)

lms/envs/common.py

@@ -101,6 +101,9 @@ MITX_FEATURES = {
     # Turn on a page that lets staff enter Python code to be run in the
     # sandbox, for testing whether it's enabled properly.
     'ENABLE_DEBUG_RUN_PYTHON': False,
+
+    # Enable URL that shows information about the status of variuous services
+    'ENABLE_SERVICE_STATUS': False,
 }
 
 # Used for A/B testing
@@ -582,7 +585,52 @@ PIPELINE_YUI_BINARY = 'yui-compressor'
 # Setting that will only affect the MITx version of django-pipeline until our changes are merged upstream
 PIPELINE_COMPILE_INPLACE = True
 
-################################### APPS #######################################
+################################# CELERY ######################################
+
+# Message configuration
+
+CELERY_TASK_SERIALIZER = 'json'
+CELERY_RESULT_SERIALIZER = 'json'
+
+CELERY_MESSAGE_COMPRESSION = 'gzip'
+
+# Results configuration
+
+CELERY_IGNORE_RESULT = False
+CELERY_STORE_ERRORS_EVEN_IF_IGNORED = True
+
+# Events configuration
+
+CELERY_TRACK_STARTED = True
+
+CELERY_SEND_EVENTS = True
+CELERY_SEND_TASK_SENT_EVENT = True
+
+# Exchange configuration
+
+CELERY_DEFAULT_EXCHANGE = 'edx.core'
+CELERY_DEFAULT_EXCHANGE_TYPE = 'direct'
+
+# Queues configuration
+
+HIGH_PRIORITY_QUEUE = 'edx.core.high'
+DEFAULT_PRIORITY_QUEUE = 'edx.core.default'
+LOW_PRIORITY_QUEUE = 'edx.core.low'
+
+CELERY_QUEUE_HA_POLICY = 'all'
+
+CELERY_CREATE_MISSING_QUEUES = True
+
+CELERY_DEFAULT_QUEUE = DEFAULT_PRIORITY_QUEUE
+CELERY_DEFAULT_ROUTING_KEY = DEFAULT_PRIORITY_QUEUE
+
+CELERY_QUEUES = {
+    HIGH_PRIORITY_QUEUE: {},
+    LOW_PRIORITY_QUEUE: {},
+    DEFAULT_PRIORITY_QUEUE: {}
+}
+
+################################### APPS ######################################
 INSTALLED_APPS = (
     # Standard ones that are always installed...
     'django.contrib.auth',
@@ -591,8 +639,12 @@ INSTALLED_APPS = (
     'django.contrib.messages',
     'django.contrib.sessions',
     'django.contrib.sites',
+    'djcelery',
     'south',
 
+    # Monitor the status of services
+    'service_status',
+
     # For asset pipelining
     'pipeline',
     'staticfiles',
@@ -639,4 +691,3 @@ INSTALLED_APPS = (
     # Student notes
     'notes',
 )
-

lms/envs/dev.py

@@ -22,8 +22,7 @@ MITX_FEATURES['FORCE_UNIVERSITY_DOMAIN'] = None		# show all university courses i
 MITX_FEATURES['ENABLE_MANUAL_GIT_RELOAD'] = True
 MITX_FEATURES['ENABLE_PSYCHOMETRICS'] = False    # real-time psychometrics (eg item response theory analysis in instructor dashboard)
 MITX_FEATURES['ENABLE_INSTRUCTOR_ANALYTICS'] = True
-
-
+MITX_FEATURES['ENABLE_SERVICE_STATUS'] = True
 
 WIKI_ENABLED = True
 
@@ -143,7 +142,7 @@ if os.path.isdir(DATA_DIR):
 
 MITX_VERSION_STRING = os.popen('cd %s; git describe' % REPO_ROOT).read().strip()
 
-################################# Open ended grading config  #####################
+############################ Open ended grading config  #####################
 
 OPEN_ENDED_GRADING_INTERFACE = {
     'url' : 'http://127.0.0.1:3033/',
@@ -154,7 +153,7 @@ OPEN_ENDED_GRADING_INTERFACE = {
     'grading_controller' : 'grading_controller'
 }
 
-################################ LMS Migration #################################
+############################## LMS Migration ##################################
 MITX_FEATURES['ENABLE_LMS_MIGRATION'] = True
 MITX_FEATURES['ACCESS_REQUIRE_STAFF_FOR_COURSE'] = False   # require that user be in the staff_* group to be able to enroll
 MITX_FEATURES['USE_XQA_SERVER'] = 'http://xqa:server@content-qa.mitx.mit.edu/xqa'
@@ -164,6 +163,7 @@ INSTALLED_APPS += ('lms_migration',)
 LMS_MIGRATION_ALLOWED_IPS = ['127.0.0.1']
 
 ################################ OpenID Auth #################################
+
 MITX_FEATURES['AUTH_USE_OPENID'] = True
 MITX_FEATURES['AUTH_USE_OPENID_PROVIDER'] = True
 MITX_FEATURES['BYPASS_ACTIVATION_EMAIL_FOR_EXTAUTH'] = True
@@ -173,16 +173,22 @@ INSTALLED_APPS += ('django_openid_auth',)
 
 OPENID_CREATE_USERS = False
 OPENID_UPDATE_DETAILS_FROM_SREG = True
-OPENID_SSO_SERVER_URL = 'https://www.google.com/accounts/o8/id'  	# TODO: accept more endpoints
+OPENID_SSO_SERVER_URL = 'https://www.google.com/accounts/o8/id'  # TODO: accept more endpoints
 OPENID_USE_AS_ADMIN_LOGIN = False
 
 OPENID_PROVIDER_TRUSTED_ROOTS = ['*']
 
-################################ MIT Certificates SSL Auth #################################
+######################## MIT Certificates SSL Auth ############################
 
 MITX_FEATURES['AUTH_USE_MIT_CERTIFICATES'] = True
 
-################################ DEBUG TOOLBAR #################################
+################################# CELERY ######################################
+
+# By default don't use a worker, execute tasks as if they were local functions
+CELERY_ALWAYS_EAGER = True
+
+################################ DEBUG TOOLBAR ################################
+
 INSTALLED_APPS += ('debug_toolbar',)
 MIDDLEWARE_CLASSES += ('django_comment_client.utils.QueryCountDebugMiddleware',
                        'debug_toolbar.middleware.DebugToolbarMiddleware',)
@@ -208,7 +214,9 @@ DEBUG_TOOLBAR_PANELS = (
 DEBUG_TOOLBAR_CONFIG = {
     'INTERCEPT_REDIRECTS': False
 }
-############################ FILE UPLOADS (for discussion forums) #############################
+
+#################### FILE UPLOADS (for discussion forums) #####################
+
 DEFAULT_FILE_STORAGE = 'django.core.files.storage.FileSystemStorage'
 MEDIA_ROOT = ENV_ROOT / "uploads"
 MEDIA_URL = "/static/uploads/"

lms/envs/dev_with_worker.py

+"""
+This config file follows the dev enviroment, but adds the
+requirement of a celery worker running in the background to process
+celery tasks.
+
+The worker can be executed using:
+
+django_admin.py celery worker
+"""
+
+from dev import *
+
+################################# CELERY ######################################
+
+# Requires a separate celery worker
+
+CELERY_ALWAYS_EAGER = False
+
+# Use django db as the broker and result store
+
+BROKER_URL = 'django://'
+INSTALLED_APPS += ('djcelery.transport', )
+CELERY_RESULT_BACKEND = 'database'
+DJKOMBU_POLLING_INTERVAL = 1.0
+
+# Disable transaction management because we are using a worker. Views
+# that request a task and wait for the result will deadlock otherwise.
+
+MIDDLEWARE_CLASSES = tuple(
+    c for c in MIDDLEWARE_CLASSES
+    if c != 'django.middleware.transaction.TransactionMiddleware')
+
+# Note: other alternatives for disabling transactions don't work in 1.4
+# https://code.djangoproject.com/ticket/2304
+# https://code.djangoproject.com/ticket/16039

lms/envs/test.py

@@ -18,6 +18,8 @@ MITX_FEATURES['DISABLE_START_DATES'] = True
 # Until we have discussion actually working in test mode, just turn it off
 MITX_FEATURES['ENABLE_DISCUSSION_SERVICE'] = True
 
+MITX_FEATURES['ENABLE_SERVICE_STATUS'] = True
+
 # Need wiki for courseware views to work. TODO (vshnayder): shouldn't need it.
 WIKI_ENABLED = True
 
@@ -124,7 +126,7 @@ CACHES = {
 # Dummy secret key for dev
 SECRET_KEY = '85920908f28904ed733fe576320db18cabd7b6cd'
 
-################################## OPENID ######################################
+################################## OPENID #####################################
 MITX_FEATURES['AUTH_USE_OPENID'] = True
 MITX_FEATURES['AUTH_USE_OPENID_PROVIDER'] = True
 
@@ -136,6 +138,12 @@ OPENID_PROVIDER_TRUSTED_ROOTS = ['*']
 INSTALLED_APPS += ('external_auth',)
 INSTALLED_APPS += ('django_openid_auth',)
 
+################################# CELERY ######################################
+
+CELERY_ALWAYS_EAGER = True
+CELERY_RESULT_BACKEND = 'cache'
+BROKER_TRANSPORT = 'memory'
+
 ############################ STATIC FILES #############################
 DEFAULT_FILE_STORAGE = 'django.core.files.storage.FileSystemStorage'
 MEDIA_ROOT = TEST_ROOT / "uploads"

lms/urls.py

@@ -357,6 +357,11 @@ if settings.MITX_FEATURES.get('ENABLE_SQL_TRACKING_LOGS'):
         url(r'^event_logs/(?P<args>.+)$', 'track.views.view_tracking_log'),
     )
 
+if settings.MITX_FEATURES.get('ENABLE_SERVICE_STATUS'):
+    urlpatterns += (
+        url(r'^status/', include('service_status.urls')),
+    )
+
 # FoldIt views
 urlpatterns += (
     # The path is hardcoded into their app...

rakefiles/django.rake

@@ -25,6 +25,14 @@ end
         sh(django_admin(system, args.env, 'runserver', args.options))
     end
 
+    desc "Start #{system} Celery worker"
+    task "#{system}_worker", [:options] => [:predjango] do |t, args|
+      args.with_defaults(:options => default_options[system])
+      django_admin = ENV['DJANGO_ADMIN_PATH'] || select_executable('django-admin.py', 'django-admin')
+      command = 'celery worker'
+      sh("#{django_admin} #{command} --loglevel=INFO --settings=#{system}.envs.dev_with_worker --pythonpath=. #{args.join(' ')}")
+    end
+
     # Per environment tasks
     environments(system).each do |env|
         desc "Attempt to import the settings file #{system}.envs.#{env} and report any errors"

requirements/edx/base.txt

@@ -3,8 +3,9 @@
 beautifulsoup4==4.1.3
 beautifulsoup==3.2.1
 boto==2.6.0
+celery==3.0.19
 distribute==0.6.28
-django-celery==3.0.11
+django-celery==3.0.17
 django-countries==1.5
 django-followit==0.0.3
 django-keyedcache==1.4-6