Merge pull request #19 from python-microservices/feature/add_error_handlers

Added methods for error  handler registration in Microservice's subclasses.

Author: avara1986

pyms/flask/app/__init__.py

@@ -13,13 +13,14 @@
 
 class Microservice:
     service = None
+    application = None
 
     def __init__(self, service: Text, path=__file__):
         self.service = service
         self.path = os.path.dirname(path)
 
-    def init_libs(self, app):
-        return app
+    def init_libs(self):
+        return self.application
 
     def create_app(self):
         """Initialize the Flask app, register blueprints and initialize
@@ -35,23 +36,42 @@ def create_app(self):
                     base_path=config.APPLICATION_ROOT
                     )
 
-        application = app.app
-        application.config.from_object(get_conf(service=self.service))
-        application.tracer = None
+        self.application = app.app
+        self.application._connexion_app = app
+        self.application.config.from_object(get_conf(service=self.service))
+        self.application.tracer = None
 
         # Initialize Blueprints
-        application.register_blueprint(healthcheck_blueprint)
-        self.init_libs(application)
+        self.application.register_blueprint(healthcheck_blueprint)
+
+        self.init_libs()
+        self.add_error_handlers()
+
         # Inject Modules
         formatter = CustomJsonFormatter('(timestamp) (level) (name) (module) (funcName) (lineno) (message)')
-        if not application.config["TESTING"]:
+        if not self.application.config["TESTING"]:
             log_handler = logging.StreamHandler()
 
-            application.tracer = FlaskTracer(init_jaeger_tracer(), True, application)
-            formatter.add_service_name(application.config["APP_NAME"])
-            formatter.add_trace_span(application.tracer)
+            self.application.tracer = FlaskTracer(init_jaeger_tracer(), True, self.application)
+            formatter.add_service_name(self.application.config["APP_NAME"])
+            formatter.add_trace_span(self.application.tracer)
             log_handler.setFormatter(formatter)
-            application.logger.addHandler(log_handler)
-            application.logger.setLevel(logging.INFO)
+            self.application.logger.addHandler(log_handler)
+            self.application.logger.setLevel(logging.INFO)
+
+        return self.application
+
+    def add_error_handlers(self):
+        """Subclasses will override this method in order to add specific error handlers. This should be done with
+        calls to add_error_handler method.
+        """
+        pass
+
+    def add_error_handler(self, code_or_exception, handler):
+        """Add custom handler for an error code or exception in the connexion app.
+
+        :param code_or_exception: HTTP error code or exception
+        :param handler: callback for error handler
+        """
 
-        return application
+        self.application._connexion_app.add_error_handler(code_or_exception, handler)