[OntologyManager] Use in-memory SQL backend by default

src/pycram/ontology/ontology.py

@@ -4,6 +4,7 @@
 import itertools
 import logging
 import os.path
+import sqlite3
 
 from pathlib import Path
 from typing import Callable, Dict, List, Optional, Type, Tuple, Union
@@ -22,7 +23,8 @@
 from ..designator import DesignatorDescription, ObjectDesignatorDescription
 
 from ..ontology.ontology_common import (OntologyConceptHolderStore, OntologyConceptHolder,
-                                        ONTOLOGY_SQL_BACKEND_FILE_EXTENSION)
+                                        ONTOLOGY_SQL_BACKEND_FILE_EXTENSION,
+                                        ONTOLOGY_SQL_IN_MEMORY_BACKEND)
 
 SOMA_HOME_ONTOLOGY_IRI = "http://www.ease-crc.org/ont/SOMA-HOME.owl"
 SOMA_ONTOLOGY_IRI = "http://www.ease-crc.org/ont/SOMA.owl"
@@ -35,12 +37,14 @@ class OntologyManager(object, metaclass=Singleton):
     Singleton class as the adapter accessing data of an OWL ontology, largely based on owlready2.
     """
 
-    def __init__(self, main_ontology_iri: Optional[str] = None, ontology_search_path: Optional[str] = None,
+    def __init__(self, main_ontology_iri: Optional[str] = None, main_sql_backend_filename: Optional[str] = None,
+                 ontology_search_path: Optional[str] = None,
                  use_global_default_world: bool = True):
         """
         Create the singleton object of OntologyManager class
 
         :param main_ontology_iri: Ontology IRI (Internationalized Resource Identifier), either a URL to a remote OWL file or the full name path of a local one
+        :param main_sql_backend_filename: a full file path (no need to already exist) being used as SQL backend for the ontology world. If None, in-memory is used instead
         :param ontology_search_path: directory path from which a possibly existing ontology is searched. This is appended to `owlready2.onto_path`, a global variable containing a list of directories for searching local copies of ontologies (similarly to python `sys.path` for modules/packages). If not specified, the path is "$HOME/ontologies"
         :param use_global_default_world: whether or not using the owlready2-provided global default persistent world
         """
@@ -74,6 +78,9 @@ def __init__(self, main_ontology_iri: Optional[str] = None, ontology_search_path
         #: Namespace of the main ontology
         self.main_ontology_namespace: Optional[Namespace] = None
 
+        #: SQL backend for :attr:`main_ontology_world`, being either "memory" or a full file path (no need to already exist)
+        self.main_ontology_sql_backend = main_sql_backend_filename if main_sql_backend_filename else ONTOLOGY_SQL_IN_MEMORY_BACKEND
+
         # Create the main ontology world holding triples
         self.create_main_ontology_world(use_global_default_world=use_global_default_world)
 
@@ -149,46 +156,70 @@ def get_main_ontology_dir(self) -> Optional[str]:
         return os.path.dirname(self.main_ontology_iri) if os.path.isabs(
             self.main_ontology_iri) else self.get_default_ontology_search_path()
 
+    def is_main_ontology_sql_backend_in_memory(self) -> bool:
+        """
+        Whether the main ontology's SQL backend is in-memory
+
+        :return: true if the main ontology's SQL backend is in-memory
+        """
+        return self.main_ontology_sql_backend == ONTOLOGY_SQL_IN_MEMORY_BACKEND
+
     def create_main_ontology_world(self, use_global_default_world: bool = True) -> None:
         """
         Create the main ontology world, either reusing the owlready2-provided global default ontology world or create a new one
         A backend sqlite3 file of same name with `main_ontology` is also created at the same folder with :attr:`main_ontology_iri`
         (if it is a local absolute path). The file is automatically registered as cache for the main ontology world.
 
         :param use_global_default_world: whether or not using the owlready2-provided global default persistent world
+        :param sql_backend_filename: a full file path (no need to already exist) being used as SQL backend for the ontology world. If None, memory is used instead
         """
         self.main_ontology_world = self.create_ontology_world(
-            sql_backend_filename=os.path.join(self.get_main_ontology_dir(),
-                                              f"{Path(self.main_ontology_iri).stem}{ONTOLOGY_SQL_BACKEND_FILE_EXTENSION}"),
+            sql_backend_filename=self.main_ontology_sql_backend,
             use_global_default_world=use_global_default_world)
 
     @staticmethod
     def create_ontology_world(use_global_default_world: bool = False,
                               sql_backend_filename: Optional[str] = None) -> OntologyWorld:
         """
-        Either reuse the owlready2-provided global default ontology world or create a new one
+        Either reuse the owlready2-provided global default ontology world or create a new one.
 
         :param use_global_default_world: whether or not using the owlready2-provided global default persistent world
-        :param sql_backend_filename: a full file path (no need to already exist) being used as SQL backend for the ontology world. If None, memory is used instead
+        :param sql_backend_filename: an absolute file path (no need to already exist) being used as SQL backend for the ontology world. If it is None or non-absolute path, in-memory is used instead
         :return: owlready2-provided global default ontology world or a newly created ontology world
         """
         world = default_world
-        sql_backend_path_valid = sql_backend_filename and os.path.isabs(sql_backend_filename)
-        sql_backend_name = sql_backend_filename if sql_backend_path_valid else "memory"
-        if use_global_default_world:
-            # Reuse default world
-            if sql_backend_path_valid:
-                world.set_backend(filename=sql_backend_filename, exclusive=False, enable_thread_parallelism=True)
-            else:
-                world.set_backend(exclusive=False, enable_thread_parallelism=True)
-            rospy.loginfo(f"Using global default ontology world with SQL backend: {sql_backend_name}")
-        else:
-            # Create a new world with parallelized file parsing enabled
-            if sql_backend_path_valid:
-                world = OntologyWorld(filename=sql_backend_filename, exclusive=False, enable_thread_parallelism=True)
+        sql_backend_path_absolute = (sql_backend_filename and os.path.isabs(sql_backend_filename))
+        if sql_backend_filename and (sql_backend_filename != ONTOLOGY_SQL_IN_MEMORY_BACKEND):
+            if not sql_backend_path_absolute:
+                rospy.logerr(f"For ontology world accessing, either f{ONTOLOGY_SQL_IN_MEMORY_BACKEND}"
+                              f"or an absolute path to its SQL file backend is expected: {sql_backend_filename}")
+                return default_world
+            elif not sql_backend_filename.endswith(ONTOLOGY_SQL_BACKEND_FILE_EXTENSION):
+                rospy.logerr(
+                    f"Ontology world SQL backend file path, {sql_backend_filename},"
+                    f"is expected to be of extension {ONTOLOGY_SQL_BACKEND_FILE_EXTENSION}!")
+                return default_world
+
+        sql_backend_path_valid = sql_backend_path_absolute
+        sql_backend_name = sql_backend_filename if sql_backend_path_valid else ONTOLOGY_SQL_IN_MEMORY_BACKEND
+        try:
+            if use_global_default_world:
+                # Reuse default world
+                if sql_backend_path_valid:
+                    world.set_backend(filename=sql_backend_filename, exclusive=False, enable_thread_parallelism=True)
+                else:
+                    world.set_backend(exclusive=False, enable_thread_parallelism=True)
+                rospy.loginfo(f"Using global default ontology world with SQL backend: {sql_backend_name}")
             else:
-                world = OntologyWorld(exclusive=False, enable_thread_parallelism=True)
-            rospy.loginfo(f"Created a new ontology world with SQL backend: {sql_backend_name}")
+                # Create a new world with parallelized file parsing enabled
+                if sql_backend_path_valid:
+                    world = OntologyWorld(filename=sql_backend_filename, exclusive=False, enable_thread_parallelism=True)
+                else:
+                    world = OntologyWorld(exclusive=False, enable_thread_parallelism=True)
+                rospy.loginfo(f"Created a new ontology world with SQL backend: {sql_backend_name}")
+        except sqlite3.Error as e:
+            rospy.logerr(f"Failed accessing the SQL backend of ontology world: {sql_backend_name}",
+                          e.sqlite_errorcode, e.sqlite_errorname)
         return world
 
     def create_main_ontology(self) -> bool:
@@ -223,7 +254,9 @@ def load_ontology(self, ontology_iri: str) -> Optional[Tuple[Ontology, Namespace
         # If `ontology_iri` is a local path
         if is_local_ontology_iri and not Path(ontology_iri).exists():
             # -> Create an empty ontology file if not existing
-            with open(ontology_iri, 'w'):
+            ontology_path = ontology_iri if os.path.isabs(ontology_iri) else (
+                os.path.join(self.get_main_ontology_dir(), ontology_iri))
+            with open(ontology_path, 'w'):
                 pass
 
         # Load ontology from `ontology_iri`

src/pycram/ontology/ontology_common.py

@@ -11,6 +11,7 @@
 from owlready2 import issubclass, Thing
 
 ONTOLOGY_SQL_BACKEND_FILE_EXTENSION = ".sqlite3"
+ONTOLOGY_SQL_IN_MEMORY_BACKEND = "memory"
 ONTOLOGY_OWL_FILE_EXTENSION = ".owl"
 
 

test/test_ontology.py

@@ -28,7 +28,8 @@
 
 from pycram.ontology.ontology import OntologyManager, SOMA_HOME_ONTOLOGY_IRI, SOMA_ONTOLOGY_IRI
 from pycram.ontology.ontology_common import (OntologyConceptHolderStore, OntologyConceptHolder,
-                                             ONTOLOGY_SQL_BACKEND_FILE_EXTENSION, ONTOLOGY_OWL_FILE_EXTENSION)
+                                             ONTOLOGY_SQL_BACKEND_FILE_EXTENSION, ONTOLOGY_OWL_FILE_EXTENSION,
+                                             ONTOLOGY_SQL_IN_MEMORY_BACKEND)
 
 DEFAULT_LOCAL_ONTOLOGY_IRI = "default.owl"
 class TestOntologyManager(unittest.TestCase):
@@ -40,7 +41,9 @@ class TestOntologyManager(unittest.TestCase):
     @classmethod
     def setUpClass(cls):
         # Try loading from remote `SOMA_ONTOLOGY_IRI`, which will fail given no internet access
-        cls.ontology_manager = OntologyManager(SOMA_ONTOLOGY_IRI)
+        cls.ontology_manager = OntologyManager(main_ontology_iri=SOMA_ONTOLOGY_IRI,
+                                               main_sql_backend_filename=os.path.join(Path.home(),
+                                               f"{Path(SOMA_ONTOLOGY_IRI).stem}{ONTOLOGY_SQL_BACKEND_FILE_EXTENSION}"))
         if cls.ontology_manager.initialized():
             cls.soma = cls.ontology_manager.soma
             cls.dul = cls.ontology_manager.dul
@@ -49,6 +52,7 @@ def setUpClass(cls):
             cls.soma = None
             cls.dul = None
             cls.ontology_manager.main_ontology_iri = DEFAULT_LOCAL_ONTOLOGY_IRI
+            cls.ontology_manager.main_ontology_sql_backend = ONTOLOGY_SQL_IN_MEMORY_BACKEND
             cls.ontology_manager.create_main_ontology_world()
             cls.ontology_manager.create_main_ontology()
         cls.main_ontology = cls.ontology_manager.main_ontology
@@ -57,9 +61,8 @@ def setUpClass(cls):
     def tearDownClass(cls):
         save_dir = cls.ontology_manager.get_main_ontology_dir()
         owl_filepath = f"{save_dir}/{Path(cls.ontology_manager.main_ontology_iri).stem}{ONTOLOGY_OWL_FILE_EXTENSION}"
-        sql_filepath = f"{save_dir}/{Path(owl_filepath).stem}{ONTOLOGY_SQL_BACKEND_FILE_EXTENSION}"
         os.remove(owl_filepath)
-        cls.remove_sql_file(sql_filepath)
+        cls.remove_sql_file(cls.ontology_manager.main_ontology_sql_backend)
 
     @classmethod
     def remove_sql_file(cls, sql_filepath: str):
@@ -299,10 +302,11 @@ def coresidents(a: reasoning_ontology.Entity, b: reasoning_ontology.Entity) -> b
     def test_ontology_save(self):
         save_dir = self.ontology_manager.get_main_ontology_dir()
         owl_filepath = f"{save_dir}/{Path(self.ontology_manager.main_ontology_iri).stem}{ONTOLOGY_OWL_FILE_EXTENSION}"
-        sql_filepath = f"{save_dir}/{Path(owl_filepath).stem}{ONTOLOGY_SQL_BACKEND_FILE_EXTENSION}"
         self.assertTrue(self.ontology_manager.save(owl_filepath))
         self.assertTrue(Path(owl_filepath).is_file())
-        self.assertTrue(Path(sql_filepath).is_file())
+        sql_backend = self.ontology_manager.main_ontology_sql_backend
+        if sql_backend != ONTOLOGY_SQL_IN_MEMORY_BACKEND:
+            self.assertTrue(Path(sql_backend).is_file())
 
 if __name__ == '__main__':
     unittest.main()