Make sure data_dir is used for default result backend DB

doc/source/admin/galaxy_options.rst

@@ -5154,9 +5154,10 @@
     only if you have setup a Celery worker for Galaxy and you have
     configured the `celery_conf` option below. Specifically, you need
     to set the `result_backend` option in the `celery_conf` option to
-    a valid Celery result backend URL. By default a SQLite database is
-    used for storing task results, please use a more robust backend
-    for production setups like Redis. For details, see
+    a valid Celery result backend URL. By default, Galaxy uses an
+    SQLite database at '<data_dir>/results.sqlite' for storing task
+    results. Please use a more robust backend for production setups
+    like Redis. For details, see
     https://docs.galaxyproject.org/en/master/admin/production.html#use-celery-for-asynchronous-tasks
 :Default: ``false``
 :Type: bool

lib/galaxy/config/__init__.py

@@ -1082,6 +1082,9 @@ class GalaxyAppConfiguration(BaseAppConfiguration, CommonConfigurationMixin):
             self.amqp_internal_connection = (
                 f"sqlalchemy+sqlite:///{self._in_data_dir('control.sqlite')}?isolation_level=IMMEDIATE"
             )
+
+        self._process_celery_config()
+
         self.pretty_datetime_format = expand_pretty_datetime_format(self.pretty_datetime_format)
         try:
             with open(self.user_preferences_extra_conf_path) as stream:
@@ -1203,6 +1206,16 @@ class GalaxyAppConfiguration(BaseAppConfiguration, CommonConfigurationMixin):
         else:
             _load_theme(self.themes_config_file, self.themes)
 
+    def _process_celery_config(self):
+        if self.celery_conf:
+            result_backend = self.celery_conf.get("result_backend")
+            if result_backend:
+                # If the result_backend is the default SQLite database, we need to
+                # ensure that the correct data directory is used.
+                if "results.sqlite" in result_backend:
+                    result_backend = f"db+sqlite:///{self._in_data_dir('results.sqlite')}?isolation_level=IMMEDIATE"
+                self.celery_conf["result_backend"] = result_backend
+
     def _check_database_connection_strings(self):
         """
         Verify connection URI strings in galaxy's configuration are parseable with urllib.

lib/galaxy/config/sample/galaxy.yml.sample

@@ -2761,9 +2761,10 @@ galaxy:
   # only if you have setup a Celery worker for Galaxy and you have
   # configured the `celery_conf` option below. Specifically, you need to
   # set the `result_backend` option in the `celery_conf` option to a
-  # valid Celery result backend URL. By default a SQLite database is
-  # used for storing task results, please use a more robust backend for
-  # production setups like Redis. For details, see
+  # valid Celery result backend URL. By default, Galaxy uses an SQLite
+  # database at '<data_dir>/results.sqlite' for storing task results.
+  # Please use a more robust backend for production setups like Redis.
+  # For details, see
   # https://docs.galaxyproject.org/en/master/admin/production.html#use-celery-for-asynchronous-tasks
   #enable_celery_tasks: false
 

lib/galaxy/config/schemas/config_schema.yml

@@ -3764,8 +3764,8 @@ mapping:
           Activate this only if you have setup a Celery worker for Galaxy and you have
           configured the `celery_conf` option below. Specifically, you need to set the
           `result_backend` option in the `celery_conf` option to a valid Celery result
-          backend URL. By default a SQLite database is used for storing task results, please
-          use a more robust backend for production setups like Redis.
+          backend URL. By default, Galaxy uses an SQLite database at '<data_dir>/results.sqlite' for storing task results.
+          Please use a more robust backend for production setups like Redis.
           For details, see https://docs.galaxyproject.org/en/master/admin/production.html#use-celery-for-asynchronous-tasks
           
       celery_conf: