#241: Add non-backend specific infrastructure for /ping

datagateway_api/common/backend.py

@@ -6,6 +6,15 @@ class Backend(ABC):
     Abstact base class for implementations of a backend to inherit from
     """
 
+    @abstractmethod
+    def ping(self):
+        """
+        Endpoint requiring no authentication to check the API is alive and does a basic
+        check to ensure the connection method to ICAT is working
+        :returns: String to tell user the API is OK
+        """
+        pass
+
     @abstractmethod
     def login(self, credentials):
         """

datagateway_api/common/constants.py

@@ -6,3 +6,4 @@
 class Constants:
     PYTHON_ICAT_DISTNCT_CONDITION = "!= null"
     TEST_MOD_CREATE_DATETIME = datetime(2000, 1, 1, tzinfo=tzlocal())
+    PING_OK_RESPONSE = "DataGateway API OK"

datagateway_api/src/api_start_utils.py

@@ -18,6 +18,7 @@
     get_id_endpoint,
 )
 from datagateway_api.src.resources.entities.entity_endpoint_dict import endpoints
+from datagateway_api.src.resources.non_entities.ping_endpoint import ping_endpoint
 from datagateway_api.src.resources.non_entities.sessions_endpoints import (
     session_endpoints,
 )
@@ -161,6 +162,11 @@ def create_api_endpoints(flask_app, api, spec):
     )
     spec.path(resource=count_instrument_investigation_resource, api=api)
 
+    # Ping endpoint
+    ping_resource = ping_endpoint(backend, client_pool=icat_client_pool)
+    api.add_resource(ping_resource, "/ping")
+    spec.path(resource=ping_resource, api=api)
+
 
 def openapi_config(spec):
     # Reorder paths (e.g. get, patch, post) so openapi.yaml only changes when there's a

datagateway_api/src/resources/non_entities/ping_endpoint.py

@@ -0,0 +1,39 @@
+from flask_restful import Resource
+
+
+def ping_endpoint(backend, **kwargs):
+    """
+    Generate a flask_restful Resource class using the configured backend. In main.py
+    these generated classes are registered with the api e.g.
+    `api.add_resource(get_endpoint("Datafiles", DATAFILE), "/datafiles")`
+
+    :param backend: The backend instance used for processing requests
+    :type backend: :class:`DatabaseBackend` or :class:`PythonICATBackend`
+    :return: The generated ping endpoint class
+    """
+
+    class Ping(Resource):
+        def get(self):
+            """
+            Pings the connection method to ensure the API is responsive
+            :return: String: A standard OK message, 200
+            ---
+            summary: Ping API connection method
+            description: Pings the API's connection method to check responsiveness
+            tags:
+              - Ping
+            responses:
+              200:
+                description: Success - the API is responsive on the backend configured
+                content:
+                  application/json:
+                    schema:
+                      type: string
+                      description: OK message
+                      example: DataGateway API OK
+              500:
+                description: Pinging the API's connection method has gone wrong
+            """
+            return backend.ping(**kwargs), 200
+
+    return Ping