From 35bd38d677b247bb6421fbea49fc9b3fb0eced5d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Carlos=20Andr=C3=A9s=20Rocha?= <rocha@edx.org>
Date: Wed, 3 Apr 2013 17:33:11 -0400
Subject: [PATCH] Add status app with simple view to check celery workers

---
 cms/envs/common.py                           |  3 +
 cms/envs/dev.py                              |  3 +
 cms/envs/test.py                             |  2 +
 cms/urls.py                                  |  6 ++
 common/djangoapps/service_status/__init__.py |  3 +
 common/djangoapps/service_status/tasks.py    | 25 +++++++++
 common/djangoapps/service_status/test.py     | 47 ++++++++++++++++
 common/djangoapps/service_status/urls.py     | 15 +++++
 common/djangoapps/service_status/views.py    | 59 ++++++++++++++++++++
 lms/envs/common.py                           |  3 +
 lms/envs/dev.py                              |  2 +-
 lms/envs/test.py                             |  2 +
 lms/urls.py                                  |  5 ++
 13 files changed, 174 insertions(+), 1 deletion(-)
 create mode 100644 common/djangoapps/service_status/__init__.py
 create mode 100644 common/djangoapps/service_status/tasks.py
 create mode 100644 common/djangoapps/service_status/test.py
 create mode 100644 common/djangoapps/service_status/urls.py
 create mode 100644 common/djangoapps/service_status/views.py

diff --git a/cms/envs/common.py b/cms/envs/common.py
index fb61db4d73..0aca432654 100644
--- a/cms/envs/common.py
+++ b/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
 
diff --git a/cms/envs/dev.py b/cms/envs/dev.py
index a05ad5731b..f3080c356f 100644
--- a/cms/envs/dev.py
+++ b/cms/envs/dev.py
@@ -156,5 +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'
diff --git a/cms/envs/test.py b/cms/envs/test.py
index 4362aaaac0..c4d2b2d972 100644
--- a/cms/envs/test.py
+++ b/cms/envs/test.py
@@ -126,3 +126,5 @@ SEGMENT_IO_KEY = '***REMOVED***'
 
 # disable NPS survey in test mode
 MITX_FEATURES['STUDIO_NPS_SURVEY'] = False
+
+MITX_FEATURES['ENABLE_SERVICE_STATUS'] = True
diff --git a/cms/urls.py b/cms/urls.py
index 3b91eceb44..cdeea35cb7 100644
--- a/cms/urls.py
+++ b/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
diff --git a/common/djangoapps/service_status/__init__.py b/common/djangoapps/service_status/__init__.py
new file mode 100644
index 0000000000..e90be0088e
--- /dev/null
+++ b/common/djangoapps/service_status/__init__.py
@@ -0,0 +1,3 @@
+"""
+Stub for a Django app to report the status of various services
+"""
diff --git a/common/djangoapps/service_status/tasks.py b/common/djangoapps/service_status/tasks.py
new file mode 100644
index 0000000000..40367120b2
--- /dev/null
+++ b/common/djangoapps/service_status/tasks.py
@@ -0,0 +1,25 @@
+"""
+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
diff --git a/common/djangoapps/service_status/test.py b/common/djangoapps/service_status/test.py
new file mode 100644
index 0000000000..1c4f10497e
--- /dev/null
+++ b/common/djangoapps/service_status/test.py
@@ -0,0 +1,47 @@
+"""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)
diff --git a/common/djangoapps/service_status/urls.py b/common/djangoapps/service_status/urls.py
new file mode 100644
index 0000000000..c5ee44b8b6
--- /dev/null
+++ b/common/djangoapps/service_status/urls.py
@@ -0,0 +1,15 @@
+"""
+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'),
+)
diff --git a/common/djangoapps/service_status/views.py b/common/djangoapps/service_status/views.py
new file mode 100644
index 0000000000..7233cbdbda
--- /dev/null
+++ b/common/djangoapps/service_status/views.py
@@ -0,0 +1,59 @@
+"""
+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")
diff --git a/lms/envs/common.py b/lms/envs/common.py
index 64b07ef855..cc03915fb2 100644
--- a/lms/envs/common.py
+++ b/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
diff --git a/lms/envs/dev.py b/lms/envs/dev.py
index 28c9a57a16..488110655e 100644
--- a/lms/envs/dev.py
+++ b/lms/envs/dev.py
@@ -22,7 +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
 
diff --git a/lms/envs/test.py b/lms/envs/test.py
index 9f3dea3980..003f7933be 100644
--- a/lms/envs/test.py
+++ b/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'] = False
 
+MITX_FEATURES['ENABLE_SERVICE_STATUS'] = True
+
 # Need wiki for courseware views to work. TODO (vshnayder): shouldn't need it.
 WIKI_ENABLED = True
 
diff --git a/lms/urls.py b/lms/urls.py
index 99b55fdb54..bf54cfc6c0 100644
--- a/lms/urls.py
+++ b/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...