#210: Remove config calls from being added as a constant

- No real reason for this to happen, once the JSON is loaded, the values aren't changed until API restart and not modified elsewhere currently
- It's probably a good thing the request behind ICAT_PROPERTIES actually gets called on demand in case the values get changed before the API is restarted
- Ultimately, this is the cause of the issue (requiring DB_URL despite using ICAT backend)

datagateway_api/common/constants.py

@@ -1,10 +1,6 @@
 from datetime import datetime
 
-from datagateway_api.common.config import config
-
 
 class Constants:
-    DATABASE_URL = config.get_db_url()
     PYTHON_ICAT_DISTNCT_CONDITION = "!= null"
-    ICAT_PROPERTIES = config.get_icat_properties()
     TEST_MOD_CREATE_DATETIME = datetime(2000, 1, 1)

datagateway_api/common/icat/filters.py

@@ -1,6 +1,6 @@
 import logging
 
-from datagateway_api.common.constants import Constants
+from datagateway_api.common.config import config
 from datagateway_api.common.exceptions import FilterError
 from datagateway_api.common.filters import (
     DistinctFieldFilter,
@@ -163,7 +163,7 @@ def __init__(self, skip_value):
         super().__init__(skip_value)
 
     def apply_filter(self, query):
-        icat_properties = Constants.ICAT_PROPERTIES
+        icat_properties = config.get_icat_properties()
         icat_set_limit(query, self.skip_value, icat_properties["maxEntities"])
 
 

datagateway_api/src/api_start_utils.py

@@ -9,7 +9,6 @@
 
 from datagateway_api.common.backends import create_backend
 from datagateway_api.common.config import config
-from datagateway_api.common.constants import Constants
 from datagateway_api.common.database.helpers import db
 from datagateway_api.src.resources.entities.entity_endpoint import (
     get_count_endpoint,
@@ -67,7 +66,7 @@ def create_app_infrastructure(flask_app):
         backend_type = config.get_backend_type()
 
     if backend_type == "db":
-        flask_app.config["SQLALCHEMY_DATABASE_URI"] = Constants.DATABASE_URL
+        flask_app.config["SQLALCHEMY_DATABASE_URI"] = config.get_db_url()
         flask_app.config["SQLALCHEMY_TRACK_MODIFICATIONS"] = False
         db.init_app(flask_app)
 

util/icat_db_generator.py

@@ -9,7 +9,7 @@
 from sqlalchemy.orm import scoped_session, sessionmaker
 from sqlalchemy.pool import QueuePool
 
-from datagateway_api.common.constants import Constants
+from datagateway_api.common.config import config
 from datagateway_api.common.database import models
 
 parser = argparse.ArgumentParser()
@@ -38,7 +38,7 @@
 
 
 engine = create_engine(
-    Constants.DATABASE_URL, poolclass=QueuePool, pool_size=100, max_overflow=0,
+    config.get_db_url(), poolclass=QueuePool, pool_size=100, max_overflow=0,
 )
 session_factory = sessionmaker(engine)
 session = scoped_session(session_factory)()