Add Cors support in the app (#119)

* Add Cors support in the app

* Add Env var CORS_ENABLED

metadata_service/__init__.py

@@ -5,6 +5,7 @@
 import os
 import sys
 from typing import Dict, Any  # noqa: F401
+from flask_cors import CORS
 
 from flasgger import Swagger
 from flask import Flask, Blueprint
@@ -22,13 +23,15 @@
                                        UserFollowsAPI, UserOwnsAPI,
                                        UserOwnAPI, UserReadsAPI)
 
-
 # For customized flask use below arguments to override.
 FLASK_APP_MODULE_NAME = os.getenv('FLASK_APP_MODULE_NAME')
 FLASK_APP_CLASS_NAME = os.getenv('FLASK_APP_CLASS_NAME')
 FLASK_APP_KWARGS_DICT_STR = os.getenv('FLASK_APP_KWARGS_DICT')
 ROOT_DIR = os.path.dirname(os.path.abspath(__file__))
 
+# Environment Variable to enable cors
+CORS_ENABLED = os.environ.get('CORS_ENABLED', False)
+
 
 def create_app(*, config_module_class: str) -> Flask:
     """
@@ -61,6 +64,8 @@ def create_app(*, config_module_class: str) -> Flask:
     else:
         app = Flask(__name__)
 
+    if CORS_ENABLED:
+        CORS(app)
     config_module_class = \
         os.getenv('METADATA_SVC_CONFIG_MODULE_CLASS') or config_module_class
     app.config.from_object(config_module_class)

requirements.txt

@@ -45,6 +45,7 @@ amundsen-common==0.2.6
 flasgger==0.9.3
 Flask-RESTful==0.3.6
 Flask==1.0.2
+flask-cors==3.0.8
 gremlinpython==3.4.3
 aniso8601==3.0.0
 attrs==19.1.0