#150: Move Flask/API setup into functions

- This will help to specify whether a unit test should use the db or python_icat backend, to be fully implemented in future commits

datagateway_api/src/main.py

@@ -8,6 +8,7 @@
 from flask_restful import Api
 from flask_swagger_ui import get_swaggerui_blueprint
 
+from datagateway_api.common.backends import create_backend
 from datagateway_api.common.config import config
 from datagateway_api.common.exceptions import ApiError
 from datagateway_api.common.logger_setup import setup_logger
@@ -28,95 +29,108 @@
 from datagateway_api.src.swagger.apispec_flask_restful import RestfulPlugin
 from datagateway_api.src.swagger.initialise_spec import initialise_spec
 
-
-spec = APISpec(
-    title="DataGateway API",
-    version="1.0",
-    openapi_version="3.0.3",
-    plugins=[RestfulPlugin()],
-    security=[{"session_id": []}],
-)
+setup_logger()
+log = logging.getLogger()
+log.info("Logging now setup")
 
 app = Flask(__name__)
-cors = CORS(app)
-app.url_map.strict_slashes = False
-api = Api(app)
-
-
-def handle_error(e):
-    return str(e), e.status_code
-
-
-app.register_error_handler(ApiError, handle_error)
-
 
 swaggerui_blueprint = get_swaggerui_blueprint(
     "", "/openapi.json", config={"app_name": "DataGateway API OpenAPI Spec"},
 )
-
 app.register_blueprint(swaggerui_blueprint, url_prefix="/")
 
-setup_logger()
-log = logging.getLogger()
-log.info("Logging now setup")
 
-initialise_spec(spec)
+def create_app_infrastructure(app):
+    spec = APISpec(
+        title="DataGateway API",
+        version="1.0",
+        openapi_version="3.0.3",
+        plugins=[RestfulPlugin()],
+        security=[{"session_id": []}],
+    )
 
-for entity_name in endpoints:
-    get_endpoint_resource = get_endpoint(entity_name, endpoints[entity_name])
-    api.add_resource(get_endpoint_resource, f"/{entity_name.lower()}")
-    spec.path(resource=get_endpoint_resource, api=api)
+    cors = CORS(app)
+    app.url_map.strict_slashes = False
+    api = Api(app)
 
-    get_id_endpoint_resource = get_id_endpoint(entity_name, endpoints[entity_name])
-    api.add_resource(get_id_endpoint_resource, f"/{entity_name.lower()}/<int:id_>")
-    spec.path(resource=get_id_endpoint_resource, api=api)
+    app.register_error_handler(ApiError, handle_error)
 
-    get_count_endpoint_resource = get_count_endpoint(
-        entity_name, endpoints[entity_name],
-    )
-    api.add_resource(get_count_endpoint_resource, f"/{entity_name.lower()}/count")
-    spec.path(resource=get_count_endpoint_resource, api=api)
+    initialise_spec(spec)
 
-    get_find_one_endpoint_resource = get_find_one_endpoint(
-        entity_name, endpoints[entity_name],
-    )
-    api.add_resource(get_find_one_endpoint_resource, f"/{entity_name.lower()}/findone")
-    spec.path(resource=get_find_one_endpoint_resource, api=api)
+    return (api, spec)
 
 
-# Session endpoint
-api.add_resource(Sessions, "/sessions")
-spec.path(resource=Sessions, api=api)
+def handle_error(e):
+    return str(e), e.status_code
+
+
+def create_api_endpoints(app, api, spec):
+    try:
+        backend_type = app.config["TEST_BACKEND"]
+    except KeyError:
+        backend_type = config.get_backend_type()
+
+    backend = create_backend(backend_type)
+
+    for entity_name in endpoints:
+        get_endpoint_resource = get_endpoint(entity_name, endpoints[entity_name])
+        api.add_resource(get_endpoint_resource, f"/{entity_name.lower()}")
+        spec.path(resource=get_endpoint_resource, api=api)
+
+        get_id_endpoint_resource = get_id_endpoint(entity_name, endpoints[entity_name])
+        api.add_resource(get_id_endpoint_resource, f"/{entity_name.lower()}/<int:id_>")
+        spec.path(resource=get_id_endpoint_resource, api=api)
+
+        get_count_endpoint_resource = get_count_endpoint(
+            entity_name, endpoints[entity_name],
+        )
+        api.add_resource(get_count_endpoint_resource, f"/{entity_name.lower()}/count")
+        spec.path(resource=get_count_endpoint_resource, api=api)
+
+        get_find_one_endpoint_resource = get_find_one_endpoint(
+            entity_name, endpoints[entity_name],
+        )
+        api.add_resource(
+            get_find_one_endpoint_resource, f"/{entity_name.lower()}/findone"
+        )
+        spec.path(resource=get_find_one_endpoint_resource, api=api)
+
+    # Session endpoint
+    api.add_resource(Sessions, "/sessions")
+    spec.path(resource=Sessions, api=api)
+
+    # Table specific endpoints
+    api.add_resource(InstrumentsFacilityCycles, "/instruments/<int:id_>/facilitycycles")
+    spec.path(resource=InstrumentsFacilityCycles, api=api)
+    api.add_resource(
+        InstrumentsFacilityCyclesCount, "/instruments/<int:id_>/facilitycycles/count",
+    )
+    spec.path(resource=InstrumentsFacilityCyclesCount, api=api)
+    api.add_resource(
+        InstrumentsFacilityCyclesInvestigations,
+        "/instruments/<int:instrument_id>/facilitycycles/<int:cycle_id>/investigations",
+    )
+    spec.path(resource=InstrumentsFacilityCyclesInvestigations, api=api)
+    api.add_resource(
+        InstrumentsFacilityCyclesInvestigationsCount,
+        "/instruments/<int:instrument_id>/facilitycycles/<int:cycle_id>/investigations"
+        "/count",
+    )
+    spec.path(resource=InstrumentsFacilityCyclesInvestigationsCount, api=api)
 
-# Table specific endpoints
-api.add_resource(InstrumentsFacilityCycles, "/instruments/<int:id_>/facilitycycles")
-spec.path(resource=InstrumentsFacilityCycles, api=api)
-api.add_resource(
-    InstrumentsFacilityCyclesCount, "/instruments/<int:id_>/facilitycycles/count",
-)
-spec.path(resource=InstrumentsFacilityCyclesCount, api=api)
-api.add_resource(
-    InstrumentsFacilityCyclesInvestigations,
-    "/instruments/<int:instrument_id>/facilitycycles/<int:cycle_id>/investigations",
-)
-spec.path(resource=InstrumentsFacilityCyclesInvestigations, api=api)
-api.add_resource(
-    InstrumentsFacilityCyclesInvestigationsCount,
-    "/instruments/<int:instrument_id>/facilitycycles/<int:cycle_id>/investigations"
-    "/count",
-)
-spec.path(resource=InstrumentsFacilityCyclesInvestigationsCount, api=api)
 
-# Reorder paths (e.g. get, patch, post) so openapi.yaml only changes when there's a
-# change to the Swagger docs, rather than changing on each startup
-log.debug("Reordering OpenAPI docs to alphabetical order")
-for entity_data in spec._paths.values():
-    for endpoint_name in sorted(entity_data.keys()):
-        entity_data.move_to_end(endpoint_name)
+def openapi_config(spec):
+    # Reorder paths (e.g. get, patch, post) so openapi.yaml only changes when there's a
+    # change to the Swagger docs, rather than changing on each startup
+    log.debug("Reordering OpenAPI docs to alphabetical order")
+    for entity_data in spec._paths.values():
+        for endpoint_name in sorted(entity_data.keys()):
+            entity_data.move_to_end(endpoint_name)
 
-openapi_spec_path = Path(__file__).parent / "swagger/openapi.yaml"
-with open(openapi_spec_path, "w") as f:
-    f.write(spec.to_yaml())
+    openapi_spec_path = Path(__file__).parent / "swagger/openapi.yaml"
+    with open(openapi_spec_path, "w") as f:
+        f.write(spec.to_yaml())
 
 
 @app.route("/openapi.json")
@@ -127,6 +141,9 @@ def specs():
 
 
 if __name__ == "__main__":
+    api, spec = create_app_infrastructure()
+    create_api_endpoints(app, api, spec)
+    openapi_config(spec)
     app.run(
         host=config.get_host(), port=config.get_port(), debug=config.is_debug_mode(),
     )