Include a StatusRequestHandler to make things easy

docs/request_handler.rst

@@ -9,3 +9,14 @@ functionality for interacting with PostgreSQL.
     :undoc-members:
     :private-members:
     :member-order: bysource
+
+The :class:`~sprockets_postgres.StatusRequestHandler` is a Tornado
+:class:`tornado.web.RequestHandler` that can be used for application health
+monitoring. If the Postgres connection is unavailable, it will report the
+API as unavailable and return a 503 status code.
+
+.. autoclass:: sprockets_postgres.StatusRequestHandler
+    :members:
+    :undoc-members:
+    :private-members:
+    :member-order: bysource

sprockets_postgres.py

@@ -717,3 +717,21 @@ class RequestHandlerMixin:
         else:
             LOGGER.debug('Postgres query %s duration: %s',
                          metric_name, duration)
+
+
+class StatusRequestHandler(web.RequestHandler):
+    """A RequestHandler that can be used to expose API health or status"""
+
+    async def get(self, *_args, **_kwarg):
+        postgres = await self.application.postgres_status()
+        if not postgres['available']:
+            self.set_status(503)
+        self.write({
+            'application': self.settings.get('service', 'unknown'),
+            'environment': self.settings.get('environment', 'unknown'),
+            'postgres': {
+                'pool_free': postgres['pool_free'],
+                'pool_size': postgres['pool_size']
+            },
+            'status': 'ok' if postgres['available'] else 'unavailable',
+            'version': self.settings.get('version', 'unknown')})

tests.py

@@ -175,15 +175,6 @@ class NoRowRequestHandler(RequestHandler):
             'rows': self.cast_data(result.rows)})
 
 
-class StatusRequestHandler(RequestHandler):
-
-    async def get(self):
-        status = await self.application.postgres_status()
-        if not status['available']:
-            self.set_status(503, 'Database Unavailable')
-        await self.finish(status)
-
-
 class TransactionRequestHandler(RequestHandler):
 
     GET_SQL = """\
@@ -315,7 +306,7 @@ class TestCase(testing.SprocketsHttpTestCase):
             web.url('/no-error', NoErrorRequestHandler),
             web.url('/no-row', NoRowRequestHandler),
             web.url('/row-count-no-rows', RowCountNoRowsRequestHandler),
-            web.url('/status', StatusRequestHandler),
+            web.url('/status', sprockets_postgres.StatusRequestHandler),
             web.url('/timeout-error', TimeoutErrorRequestHandler),
             web.url('/transaction', TransactionRequestHandler),
             web.url('/transaction/(?P<test_id>.*)', TransactionRequestHandler),
@@ -329,29 +320,31 @@ class RequestHandlerMixinTestCase(TestCase):
     def test_postgres_status(self):
         response = self.fetch('/status')
         data = json.loads(response.body)
-        self.assertTrue(data['available'])
+        self.assertEqual(data['status'], 'ok')
-        self.assertGreaterEqual(data['pool_size'], 1)
+        self.assertGreaterEqual(data['postgres']['pool_size'], 1)
-        self.assertGreaterEqual(data['pool_free'], 1)
+        self.assertGreaterEqual(data['postgres']['pool_free'], 1)
 
     @mock.patch('aiopg.pool.Pool.acquire')
     def test_postgres_status_connect_error(self, acquire):
         acquire.side_effect = asyncio.TimeoutError()
         response = self.fetch('/status')
         self.assertEqual(response.code, 503)
-        self.assertFalse(json.loads(response.body)['available'])
+        data = json.loads(response.body)
+        self.assertEqual(data['status'], 'unavailable')
 
     def test_postgres_status_not_connected(self):
         self.app._postgres_connected.clear()
         response = self.fetch('/status')
         self.assertEqual(response.code, 503)
-        self.assertFalse(json.loads(response.body)['available'])
+        data = json.loads(response.body)
+        self.assertEqual(data['status'], 'unavailable')
 
     @mock.patch('aiopg.cursor.Cursor.execute')
     def test_postgres_status_error(self, execute):
         execute.side_effect = asyncio.TimeoutError()
         response = self.fetch('/status')
-        self.assertEqual(response.code, 503)
+        data = json.loads(response.body)
-        self.assertFalse(json.loads(response.body)['available'])
+        self.assertEqual(data['status'], 'unavailable')
 
     def test_postgres_callproc(self):
         response = self.fetch('/callproc')