refactor: move config to its own class #258

- This change has been made so the config can be mocked in tests

datagateway_api/src/api_start_utils.py

@@ -7,12 +7,12 @@
 from flask_restful import Api
 from flask_swagger_ui import get_swaggerui_blueprint
 
-from datagateway_api.src.common.config import config
+from datagateway_api.src.common.config import Config
 
 # Only attempt to create a DataGateway API backend if the datagateway_api object
 # is present in the config. This ensures that the API does not error on startup
 # due to an AttributeError exception being thrown if the object is missing.
-if config.datagateway_api is not None:
+if Config.config.datagateway_api is not None:
     from datagateway_api.src.datagateway_api.backends import create_backend
 from datagateway_api.src.datagateway_api.database.helpers import db  # noqa: I202
 from datagateway_api.src.datagateway_api.icat.icat_client_pool import create_client_pool
@@ -73,15 +73,17 @@ def create_app_infrastructure(flask_app):
     flask_app.url_map.strict_slashes = False
     api = CustomErrorHandledApi(flask_app)
 
-    if config.datagateway_api is not None:
+    if Config.config.datagateway_api is not None:
         try:
             backend_type = flask_app.config["TEST_BACKEND"]
-            config.datagateway_api.set_backend_type(backend_type)
+            Config.config.datagateway_api.set_backend_type(backend_type)
         except KeyError:
-            backend_type = config.datagateway_api.backend
+            backend_type = Config.config.datagateway_api.backend
 
         if backend_type == "db":
-            flask_app.config["SQLALCHEMY_DATABASE_URI"] = config.datagateway_api.db_url
+            flask_app.config[
+                "SQLALCHEMY_DATABASE_URI"
+            ] = Config.config.datagateway_api.db_url
             flask_app.config["SQLALCHEMY_TRACK_MODIFICATIONS"] = False
             db.init_app(flask_app)
 
@@ -92,12 +94,12 @@ def create_app_infrastructure(flask_app):
 
 def create_api_endpoints(flask_app, api, spec):
     # DataGateway API endpoints
-    if config.datagateway_api is not None:
+    if Config.config.datagateway_api is not None:
         try:
             backend_type = flask_app.config["TEST_BACKEND"]
-            config.datagateway_api.set_backend_type(backend_type)
+            Config.config.datagateway_api.set_backend_type(backend_type)
         except KeyError:
-            backend_type = config.datagateway_api.backend
+            backend_type = Config.config.datagateway_api.backend
 
         backend = create_backend(backend_type)
 
@@ -106,7 +108,7 @@ def create_api_endpoints(flask_app, api, spec):
             # Create client pool
             icat_client_pool = create_client_pool()
 
-        datagateway_api_extension = config.datagateway_api.extension
+        datagateway_api_extension = Config.config.datagateway_api.extension
         for entity_name in endpoints:
             get_endpoint_resource = get_endpoint(
                 entity_name,
@@ -220,8 +222,8 @@ def create_api_endpoints(flask_app, api, spec):
         spec.path(resource=ping_resource, api=api)
 
     # Search API endpoints
-    if config.search_api is not None:
-        search_api_extension = config.search_api.extension
+    if Config.config.search_api is not None:
+        search_api_extension = Config.config.search_api.extension
         search_api_entity_endpoints = ["datasets", "documents", "instruments"]
 
         for entity_name in search_api_entity_endpoints:
@@ -271,7 +273,7 @@ def create_api_endpoints(flask_app, api, spec):
 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
-    if config.generate_swagger:
+    if Config.config.generate_swagger:
         log.debug("Reordering OpenAPI docs to alphabetical order")
         for entity_data in spec._paths.values():
             for endpoint_name in sorted(entity_data.keys()):

datagateway_api/src/common/config.py

@@ -126,8 +126,6 @@ class SearchAPI(BaseModel):
     validation of the SearchAPI config data using Python type annotations.
     """
 
-    client_pool_init_size: StrictInt
-    client_pool_max_size: StrictInt
     extension: StrictStr
     icat_check_cert: StrictBool
     icat_url: StrictStr
@@ -215,4 +213,7 @@ def validate_api_extensions(cls, value, values):  # noqa: B902, N805
         return value
 
 
-config = APIConfig.load()
+class Config:
+    """Class containing config as a class variable so it can mocked during testing"""
+
+    config = APIConfig.load()

datagateway_api/src/common/logger_setup.py

@@ -1,9 +1,9 @@
 import logging.config
 from pathlib import Path
 
-from datagateway_api.src.common.config import config
+from datagateway_api.src.common.config import Config
 
-LOG_FILE_NAME = Path(config.log_location)
+LOG_FILE_NAME = Path(Config.config.log_location)
 logger_config = {
     "version": 1,
     "formatters": {
@@ -14,15 +14,15 @@
     },
     "handlers": {
         "default": {
-            "level": config.log_level,
+            "level": Config.config.log_level,
             "formatter": "default",
             "class": "logging.handlers.RotatingFileHandler",
             "filename": LOG_FILE_NAME,
             "maxBytes": 5000000,
             "backupCount": 10,
         },
     },
-    "root": {"level": config.log_level, "handlers": ["default"]},
+    "root": {"level": Config.config.log_level, "handlers": ["default"]},
 }
 
 

datagateway_api/src/datagateway_api/icat/filters.py

@@ -1,6 +1,6 @@
 import logging
 
-from datagateway_api.src.common.config import config
+from datagateway_api.src.common.config import Config
 from datagateway_api.src.common.exceptions import FilterError
 from datagateway_api.src.common.filters import (
     DistinctFieldFilter,
@@ -215,7 +215,8 @@ def __init__(self, skip_value):
 
     def apply_filter(self, query):
         icat_properties = get_icat_properties(
-            config.datagateway_api.icat_url, config.datagateway_api.icat_check_cert,
+            Config.config.datagateway_api.icat_url,
+            Config.config.datagateway_api.icat_check_cert,
         )
         icat_set_limit(query, self.skip_value, icat_properties["maxEntities"])
 

datagateway_api/src/datagateway_api/icat/icat_client_pool.py

@@ -3,7 +3,7 @@
 from icat.client import Client
 from object_pool import ObjectPool
 
-from datagateway_api.src.common.config import config
+from datagateway_api.src.common.config import Config
 
 log = logging.getLogger()
 
@@ -13,12 +13,12 @@ class ICATClient(Client):
 
     def __init__(self, client_use="datagateway_api"):
         if client_use == "datagateway_api":
-            icat_url = config.datagateway_api.icat_url
-            icat_check_cert = config.datagateway_api.icat_check_cert
+            icat_url = Config.config.datagateway_api.icat_url
+            icat_check_cert = Config.config.datagateway_api.icat_check_cert
         else:
             # Search API use cases
-            icat_url = config.search_api.icat_url
-            icat_check_cert = config.search_api.icat_check_cert
+            icat_url = Config.config.search_api.icat_url
+            icat_check_cert = Config.config.search_api.icat_check_cert
 
         super().__init__(icat_url, checkCert=icat_check_cert)
         # When clients are cleaned up, sessions won't be logged out
@@ -41,8 +41,8 @@ def create_client_pool():
 
     return ObjectPool(
         ICATClient,
-        min_init=config.datagateway_api.client_pool_init_size,
-        max_capacity=config.datagateway_api.client_pool_max_size,
+        min_init=Config.config.datagateway_api.client_pool_init_size,
+        max_capacity=Config.config.datagateway_api.client_pool_max_size,
         max_reusable=0,
         expires=0,
     )

datagateway_api/src/datagateway_api/icat/lru_cache.py

@@ -2,7 +2,7 @@
 
 from cachetools.lru import LRUCache
 
-from datagateway_api.src.common.config import config
+from datagateway_api.src.common.config import Config
 
 log = logging.getLogger()
 
@@ -19,7 +19,7 @@ class ExtendedLRUCache(LRUCache):
     """
 
     def __init__(self):
-        super().__init__(maxsize=config.datagateway_api.client_cache_size)
+        super().__init__(maxsize=Config.config.datagateway_api.client_cache_size)
 
     def popitem(self):
         key, client = super().popitem()

datagateway_api/src/datagateway_api/query_filter_factory.py

@@ -1,6 +1,6 @@
 import logging
 
-from datagateway_api.src.common.config import config
+from datagateway_api.src.common.config import Config
 from datagateway_api.src.common.exceptions import (
     ApiError,
     FilterError,
@@ -27,7 +27,7 @@ def get_query_filter(request_filter):
         :raises FilterError: If the filter name is not recognised
         """
 
-        backend_type = config.datagateway_api.backend
+        backend_type = Config.config.datagateway_api.backend
         if backend_type == "db":
             from datagateway_api.src.datagateway_api.database.filters import (
                 DatabaseDistinctFieldFilter as DistinctFieldFilter,

datagateway_api/src/main.py

@@ -8,7 +8,7 @@
     create_openapi_endpoint,
     openapi_config,
 )
-from datagateway_api.src.common.config import config
+from datagateway_api.src.common.config import Config
 from datagateway_api.src.common.logger_setup import setup_logger
 
 setup_logger()
@@ -23,8 +23,8 @@
 
 if __name__ == "__main__":
     app.run(
-        host=config.host,
-        port=config.port,
-        debug=config.debug_mode,
-        use_reloader=config.flask_reloader,
+        host=Config.config.host,
+        port=Config.config.port,
+        debug=Config.config.debug_mode,
+        use_reloader=Config.config.flask_reloader,
     )

test/datagateway_api/db/conftest.py

@@ -3,7 +3,7 @@
 
 import pytest
 
-from datagateway_api.src.common.config import config
+from datagateway_api.src.common.config import Config
 from datagateway_api.src.common.constants import Constants
 from datagateway_api.src.datagateway_api.database.helpers import (
     delete_row_by_id,
@@ -117,7 +117,8 @@ def isis_specific_endpoint_data_db():
 @pytest.fixture()
 def final_instrument_id(flask_test_app_db, valid_db_credentials_header):
     final_instrument_result = flask_test_app_db.get(
-        f'{config.datagateway_api.extension}/instruments/findone?order="id DESC"',
+        f"{Config.config.datagateway_api.extension}/instruments/findone"
+        '?order="id DESC"',
         headers=valid_db_credentials_header,
     )
     return final_instrument_result.json["id"]
@@ -126,7 +127,8 @@ def final_instrument_id(flask_test_app_db, valid_db_credentials_header):
 @pytest.fixture()
 def final_facilitycycle_id(flask_test_app_db, valid_db_credentials_header):
     final_facilitycycle_result = flask_test_app_db.get(
-        f'{config.datagateway_api.extension}/facilitycycles/findone?order="id DESC"',
+        f"{Config.config.datagateway_api.extension}/facilitycycles/findone"
+        '?order="id DESC"',
         headers=valid_db_credentials_header,
     )
     return final_facilitycycle_result.json["id"]

test/datagateway_api/db/endpoints/test_count_with_filters_db.py

@@ -1,6 +1,6 @@
 import pytest
 
-from datagateway_api.src.common.config import config
+from datagateway_api.src.common.config import Config
 
 
 class TestDBCountWithFilters:
@@ -9,7 +9,7 @@ def test_valid_count_with_filters(
         self, flask_test_app_db, valid_db_credentials_header,
     ):
         test_response = flask_test_app_db.get(
-            f"{config.datagateway_api.extension}/investigations/count?where="
+            f"{Config.config.datagateway_api.extension}/investigations/count?where="
             '{"title": {"like": "Title for DataGateway API Testing (DB)"}}',
             headers=valid_db_credentials_header,
         )
@@ -20,7 +20,7 @@ def test_valid_no_results_count_with_filters(
         self, flask_test_app_db, valid_db_credentials_header,
     ):
         test_response = flask_test_app_db.get(
-            f"{config.datagateway_api.extension}/investigations/count?where="
+            f"{Config.config.datagateway_api.extension}/investigations/count?where="
             '{"title": {"like": "This filter should cause a404 for testing '
             'purposes..."}}',
             headers=valid_db_credentials_header,

test/datagateway_api/db/endpoints/test_findone_db.py

@@ -1,4 +1,4 @@
-from datagateway_api.src.common.config import config
+from datagateway_api.src.common.config import Config
 
 
 class TestDBFindone:
@@ -9,7 +9,7 @@ def test_valid_findone_with_filters(
         single_investigation_test_data_db,
     ):
         test_response = flask_test_app_db.get(
-            f"{config.datagateway_api.extension}/investigations/findone?where="
+            f"{Config.config.datagateway_api.extension}/investigations/findone?where="
             '{"title": {"like": "Title for DataGateway API Testing (DB)"}}',
             headers=valid_db_credentials_header,
         )
@@ -20,7 +20,7 @@ def test_valid_no_results_findone_with_filters(
         self, flask_test_app_db, valid_db_credentials_header,
     ):
         test_response = flask_test_app_db.get(
-            f"{config.datagateway_api.extension}/investigations/findone?where="
+            f"{Config.config.datagateway_api.extension}/investigations/findone?where="
             '{"title": {"eq": "This filter should cause a404 for testing '
             'purposes..."}}',
             headers=valid_db_credentials_header,

test/datagateway_api/db/endpoints/test_get_by_id_db.py

@@ -1,4 +1,4 @@
-from datagateway_api.src.common.config import config
+from datagateway_api.src.common.config import Config
 
 
 class TestDBGetByID:
@@ -10,14 +10,14 @@ def test_valid_get_with_id(
     ):
         # Need to identify the ID given to the test data
         investigation_data = flask_test_app_db.get(
-            f"{config.datagateway_api.extension}/investigations?where="
+            f"{Config.config.datagateway_api.extension}/investigations?where="
             '{"title": {"like": "Title for DataGateway API Testing (DB)"}}',
             headers=valid_db_credentials_header,
         )
         test_data_id = investigation_data.json[0]["id"]
 
         test_response = flask_test_app_db.get(
-            f"{config.datagateway_api.extension}/investigations/{test_data_id}",
+            f"{Config.config.datagateway_api.extension}/investigations/{test_data_id}",
             headers=valid_db_credentials_header,
         )
 
@@ -27,15 +27,16 @@ def test_invalid_get_with_id(
         self, flask_test_app_db, valid_db_credentials_header,
     ):
         final_investigation_result = flask_test_app_db.get(
-            f"{config.datagateway_api.extension}/investigations/findone?order="
+            f"{Config.config.datagateway_api.extension}/investigations/findone?order="
             '"id DESC"',
             headers=valid_db_credentials_header,
         )
         test_data_id = final_investigation_result.json["id"]
 
         # Adding 100 onto the ID to the most recent result should ensure a 404
         test_response = flask_test_app_db.get(
-            f"{config.datagateway_api.extension}/investigations/{test_data_id + 100}",
+            f"{Config.config.datagateway_api.extension}/investigations"
+            f"/{test_data_id + 100}",
             headers=valid_db_credentials_header,
         )