Added readiness and liveliness endpoints for all microservices

adsmutils/__init__.py

@@ -24,6 +24,7 @@
 import inspect
 from cloghandler import ConcurrentRotatingFileHandler
 from flask import Flask
+from flask import Response
 from pythonjsonlogger import jsonlogger
 from logging import Formatter
 import flask
@@ -293,6 +294,9 @@ def __init__(self, app_name, *args, **kwargs):
         self.client.mount('http://', http_adapter)
         self.before_request_funcs.setdefault(None, []).append(self._before_request)
 
+        self.add_url_rule('/ready', 'ready', self.ready)
+        self.add_url_rule('/alive', 'alive', self.alive)
+
     def _before_request(self):
         if flask.has_request_context():
             # New request will contain also key information from the original request
@@ -318,6 +322,28 @@ def close_app(self):
         self.db = None
         self.logger = None
 
+    def ready(self, key='ready'):
+        """Endpoint /ready to signal that the application is ready to receive requests"""
+        if self._db_failure():
+            return Response(json.dumps({key: False}), mimetype='application/json', status=503)
+        else:
+            return Response(json.dumps({key: True}), mimetype='application/json', status=200)
+
+    def alive(self):
+        """Endpoint /alive to signal that the application is healthy"""
+        return self.ready(key="alive")
+
+    def _db_failure(self):
+        if self.db is None:
+            return False
+        else:
+            with self.session_scope() as session:
+                try:
+                    session.execute('SELECT 1')
+                    return False
+                except:
+                    return True
+
 
     @contextmanager
     def session_scope(self):

adsmutils/tests/base.py

@@ -0,0 +1,58 @@
+# -*- coding: utf-8 -*-
+
+import testing.postgresql
+from flask_testing import TestCase
+from adsmutils import ADSFlask
+
+class TestCaseDatabase(TestCase):
+
+    postgresql_url_dict = {
+        'port': 1234,
+        'host': '127.0.0.1',
+        'user': 'postgres',
+        'database': 'test'
+    }
+    postgresql_url = 'postgresql://{user}@{host}:{port}/{database}' \
+        .format(
+        user=postgresql_url_dict['user'],
+        host=postgresql_url_dict['host'],
+        port=postgresql_url_dict['port'],
+        database=postgresql_url_dict['database']
+    )
+
+    def create_app(self):
+        '''Start the wsgi application'''
+        local_config = {
+            'SQLALCHEMY_DATABASE_URI': self.postgresql_url,
+            'SQLALCHEMY_ECHO': False,
+            'TESTING': True,
+            'PROPAGATE_EXCEPTIONS': True,
+            'TRAP_BAD_REQUEST_ERRORS': True
+        }
+        app = ADSFlask(__name__, static_folder=None, local_config=local_config)
+        return app
+
+    @classmethod
+    def setUpClass(cls):
+        cls.postgresql = \
+            testing.postgresql.Postgresql(**cls.postgresql_url_dict)
+
+    @classmethod
+    def tearDownClass(cls):
+        cls.postgresql.stop()
+
+    def setUp(self):
+        pass
+
+    def tearDown(self):
+        self.app.db.session.remove()
+        self.app.db.drop_all()
+
+class TestCase(TestCase):
+
+    def create_app(self):
+        '''Start the wsgi application'''
+        local_config = { }
+        app = ADSFlask(__name__, static_folder=None, local_config=local_config)
+        return app
+

adsmutils/tests/test_service.py

@@ -0,0 +1,53 @@
+# -*- coding: utf-8 -*-
+
+from base import TestCase, TestCaseDatabase
+import mock
+
+class TestServices(TestCase):
+
+    def test_readiness_probe(self):
+        '''Tests for the existence of a /ready route, and that it returns properly
+        formatted JSON data'''
+        r = self.client.get('/ready')
+        self.assertEqual(r.status_code, 200)
+        self.assertEqual(r.json['ready'], True)
+
+    def test_liveliness_probe(self):
+        '''Tests for the existence of a /alive route, and that it returns properly
+        formatted JSON data'''
+        r = self.client.get('/alive')
+        self.assertEqual(r.status_code, 200)
+        self.assertEqual(r.json['alive'], True)
+
+
+class TestServicesWithDatabase(TestCaseDatabase):
+
+    def test_readiness_probe(self):
+        '''Tests for the existence of a /ready route, and that it returns properly
+        formatted JSON data'''
+        r = self.client.get('/ready')
+        self.assertEqual(r.status_code, 200)
+        self.assertEqual(r.json['ready'], True)
+
+    def test_liveliness_probe(self):
+        '''Tests for the existence of a /alive route, and that it returns properly
+        formatted JSON data'''
+        r = self.client.get('/alive')
+        self.assertEqual(r.status_code, 200)
+        self.assertEqual(r.json['alive'], True)
+
+    def test_readiness_probe_with_db_failure(self):
+        '''Tests for the existence of a /ready route, and that it returns properly
+        formatted JSON data when database connection has been lost'''
+        self.app._db_failure = mock.MagicMock(return_value=True)
+        r = self.client.get('/ready')
+        self.assertEqual(r.status_code, 503)
+        self.assertEqual(r.json['ready'], False)
+
+    def test_liveliness_probe_with_db_failure(self):
+        '''Tests for the existence of a /alive route, and that it returns properly
+        formatted JSON data when database connection has been lost'''
+        self.app._db_failure = mock.MagicMock(return_value=True)
+        r = self.client.get('/alive')
+        self.assertEqual(r.status_code, 503)
+        self.assertEqual(r.json['alive'], False)

dev-requirements.txt

@@ -1,6 +1,9 @@
 pytest==2.8.2
+Flask-Testing==0.7.1
 coveralls==1.1.0
 httpretty==0.8.10
 mock==1.3.0
 coverage==4.0.1
 pytest-cov==2.2.0
+testing.postgresql==1.2.1
+psycopg2==2.7.5