(WIP) Support for Postgres as an alternative backend to sqlite

.gitignore

@@ -8,3 +8,7 @@ __pycache__
 /docs/_build
 /docs/_static
 /docs/_templates
+
+
+# Jupyter
+*.ipynb

ngshare/alembic/versions/aa00db20c10a_init.py

@@ -71,7 +71,7 @@ def upgrade():
     )
     op.create_table(
         'assignment_files_assoc_table',
-        sa.Column('left_id', sa.TEXT(), nullable=False),
+        sa.Column('left_id', sa.INTEGER(), nullable=False), # changed from TEXT
         sa.Column('right_id', sa.INTEGER(), nullable=False),
         sa.ForeignKeyConstraint(['left_id'], ['assignments._id'],),
         sa.ForeignKeyConstraint(['right_id'], ['files._id'],),
@@ -89,15 +89,15 @@ def upgrade():
     )
     op.create_table(
         'feedback_files_assoc_table',
-        sa.Column('left_id', sa.TEXT(), nullable=False),
+        sa.Column('left_id', sa.INTEGER(), nullable=False), # changed from TEXT
         sa.Column('right_id', sa.INTEGER(), nullable=False),
         sa.ForeignKeyConstraint(['left_id'], ['submissions._id'],),
         sa.ForeignKeyConstraint(['right_id'], ['files._id'],),
         sa.PrimaryKeyConstraint('left_id', 'right_id'),
     )
     op.create_table(
         'submission_files_assoc_table',
-        sa.Column('left_id', sa.TEXT(), nullable=False),
+        sa.Column('left_id', sa.INTEGER(), nullable=False), # changed from TEXT
         sa.Column('right_id', sa.INTEGER(), nullable=False),
         sa.ForeignKeyConstraint(['left_id'], ['submissions._id'],),
         sa.ForeignKeyConstraint(['right_id'], ['files._id'],),

ngshare/database/database.py

@@ -24,23 +24,23 @@
 assignment_files_assoc_table = Table(
     'assignment_files_assoc_table',
     Base.metadata,
-    Column('left_id', TEXT, ForeignKey('assignments._id'), primary_key=True),
+    Column('left_id', INTEGER, ForeignKey('assignments._id'), primary_key=True), # changed from TEXT
     Column('right_id', INTEGER, ForeignKey('files._id'), primary_key=True),
 )
 
 # Submission -> Course (One to Many)
 submission_files_assoc_table = Table(
     'submission_files_assoc_table',
     Base.metadata,
-    Column('left_id', TEXT, ForeignKey('submissions._id'), primary_key=True),
+    Column('left_id', INTEGER, ForeignKey('submissions._id'), primary_key=True), # changed from TEXT
     Column('right_id', INTEGER, ForeignKey('files._id'), primary_key=True),
 )
 
 # Submission (feedback) -> Course (One to Many)
 feedback_files_assoc_table = Table(
     'feedback_files_assoc_table',
     Base.metadata,
-    Column('left_id', TEXT, ForeignKey('submissions._id'), primary_key=True),
+    Column('left_id', INTEGER, ForeignKey('submissions._id'), primary_key=True), # changed from TEXT
     Column('right_id', INTEGER, ForeignKey('files._id'), primary_key=True),
 )
 

ngshare/database/test_database.py

@@ -19,19 +19,20 @@
 
 def clear_db(db, storage_path):
     'Remove all data from database'
-    db.query(User).delete()
-    db.query(Course).delete()
-    db.query(Assignment).delete()
-    db.query(Submission).delete()
-    db.query(File).delete()
-    db.query(InstructorAssociation).delete()
-    db.query(StudentAssociation).delete()
     for table_name in [
         'assignment_files_assoc_table',
         'submission_files_assoc_table',
         'feedback_files_assoc_table',
     ]:
         db.execute('DELETE FROM %s' % table_name)
+    db.query(InstructorAssociation).delete()
+    db.query(StudentAssociation).delete()
+    db.query(Submission).delete()
+    db.query(Assignment).delete()
+    db.query(File).delete()
+    db.query(Course).delete()
+    db.query(User).delete()
+
     db.commit()
     if storage_path is not None:
         shutil.rmtree(storage_path, ignore_errors=True)

ngshare/ngshare.py

@@ -25,6 +25,7 @@
 from jupyterhub.services.auth import HubAuthenticated
 from sqlalchemy import create_engine, or_
 from sqlalchemy.orm import sessionmaker
+from sqlalchemy_utils import database_exists, create_database
 
 try:
     from . import dbutil
@@ -944,6 +945,8 @@ def __init__(
         )
         # Connect Database
         engine = create_engine(db_url)
+        if not database_exists(engine.url):
+            create_database(engine.url)
         Base.metadata.bind = engine
         Base.metadata.create_all(engine)
         self.db_session = sessionmaker(bind=engine)

ngshare/test_ngshare.py

@@ -26,22 +26,38 @@
 application, db_name, storage_name = None, None, None
 user, hc, bu = None, None, None
 
+BACKEND_POSTGRES = "postgresql"
+BACKEND_SQLITE = "sqlite"
+
+db_backend = BACKEND_POSTGRES
+#db_backend = BACKEND_SQLITE
 
 @pytest.fixture
 def app():
+    '''Handle alternative backends'''
     'Create Tornado application for testing'
     global application, db_name, storage_name
     # Create temporary location for db and storage
+    storage_name = tempfile.mktemp('-ngshare-test-dir')
     if db_name is None:
-        db_name = tempfile.mktemp('.db')
-        storage_name = tempfile.mktemp('-ngshare-test-dir')
-    application = MyApplication(
-        '/api/',
-        'sqlite:///' + db_name,
-        storage_name,
-        admin=['root'],
-        debug=True,
-    )
+        if db_backend == BACKEND_SQLITE:
+            db_name = tempfile.mktemp('.db')
+            application = MyApplication(
+                '/api/',
+                'sqlite:///' + db_name,
+                storage_name,
+                admin=['root'],
+                debug=True,
+            )
+        elif db_backend == BACKEND_POSTGRES:
+#            db_name = tempfile.mktemp('.db')
+            application = MyApplication(
+                '/api/',
+                'postgresql://postgres:omg-a-password@localhost:5432/ngshare_test',
+                storage_name,
+                admin=['root'],
+                debug=True,
+            )
     # Mock authentication using vngshare
     MyRequestHandler.__bases__ = (MockAuth, RequestHandler, MyHelpers)
     return application
@@ -1312,7 +1328,10 @@ def test_notimpl():
 
 
 def test_clean():
-    'Clean temporary files'
+    'Clean temporary files - only relevant with an sqlite backend'
     global db_name, storage_name
-    os.remove(db_name)
-    shutil.rmtree(storage_name)
+    if db_backend == BACKEND_SQLITE:
+        os.remove(db_name)
+        shutil.rmtree(storage_name)
+    elif db_backend == BACKEND_POSTGRES:
+        pass