Merge pull request #204 from ral-facilities/bugfix/improve-db-sessions

Bugfix/improve db sessions

datagateway_api/common/database/helpers.py

@@ -3,6 +3,7 @@
 from functools import wraps
 import logging
 
+from flask_sqlalchemy import SQLAlchemy
 from sqlalchemy.orm import aliased
 
 from datagateway_api.common.database.filters import (
@@ -17,7 +18,6 @@
     INVESTIGATIONINSTRUMENT,
     SESSION,
 )
-from datagateway_api.common.database.session_manager import session_manager
 from datagateway_api.common.exceptions import (
     AuthenticationError,
     BadRequestError,
@@ -28,6 +28,8 @@
 
 log = logging.getLogger()
 
+db = SQLAlchemy()
+
 
 def requires_session_id(method):
     """
@@ -41,12 +43,11 @@ def requires_session_id(method):
     @wraps(method)
     def wrapper_requires_session(*args, **kwargs):
         log.info(" Authenticating consumer")
-        session = session_manager.get_icat_db_session()
+        session = db.session
         query = session.query(SESSION).filter(SESSION.ID == args[1]).first()
         if query is not None:
             log.info(" Closing DB session")
             session.close()
-            session.close()
             log.info(" Consumer authenticated")
             return method(*args, **kwargs)
         else:
@@ -66,7 +67,7 @@ class Query(ABC):
 
     @abstractmethod
     def __init__(self, table):
-        self.session = session_manager.get_icat_db_session()
+        self.session = db.session
         self.table = table
         self.base_query = self.session.query(table)
 
@@ -86,7 +87,12 @@ def commit_changes(self):
         Commits all changes to the database and closes the session
         """
         log.info(" Committing changes to %s", self.table)
-        self.session.commit()
+        try:
+            self.session.commit()
+        except Exception as e:
+            log.error("Error whilst committing changes to %s, rolling back", self.table)
+            self.session.rollback()
+            raise e
 
 
 class CountQuery(Query):

datagateway_api/src/api_start_utils.py

@@ -9,6 +9,8 @@
 
 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,
     get_endpoint,
@@ -58,6 +60,17 @@ def create_app_infrastructure(flask_app):
     flask_app.url_map.strict_slashes = False
     api = CustomErrorHandledApi(flask_app)
 
+    try:
+        backend_type = flask_app.config["TEST_BACKEND"]
+        config.set_backend_type(backend_type)
+    except KeyError:
+        backend_type = config.get_backend_type()
+
+    if backend_type == "db":
+        flask_app.config["SQLALCHEMY_DATABASE_URI"] = Constants.DATABASE_URL
+        flask_app.config["SQLALCHEMY_TRACK_MODIFICATIONS"] = False
+        db.init_app(flask_app)
+
     initialise_spec(spec)
 
     return (api, spec)

pyproject.toml

@@ -19,6 +19,7 @@ flask-swagger-ui = "3.25.0"
 PyYAML = "5.3.1"
 python-icat = "0.17.0"
 suds-community = "^0.8.4"
+Flask-SQLAlchemy = "^2.4.4"
 
 [tool.poetry.dev-dependencies]
 pip-tools = "5.3.1"