perf: optimize away more privilege requests

[MIGRATION] This commit contains a new version of the schema.

app/models/priv.py

@@ -47,6 +47,9 @@ class Group(db.Model):
     members = db.relationship('Member', secondary=lambda: GroupMember,
         back_populates='groups')
 
+    # Other fields populated automatically through relations:
+    #     <privileges> list of privileges
+
     def __init__(self, name, css, descr):
         self.name = name
         self.css = css
@@ -59,7 +62,7 @@ class Group(db.Model):
         * Group privileges
         """
 
-        for gp in GroupPrivilege.query.filter_by(gid=self.id).all():
+        for gp in self.privileges:
             db.session.delete(gp)
         db.session.commit()
 
@@ -67,8 +70,7 @@ class Group(db.Model):
         db.session.commit()
 
     def privs(self):
-        gps = GroupPrivilege.query.filter_by(gid=self.id).all()
-        return sorted(gp.priv for gp in gps)
+        return sorted(gp.priv for gp in self.privileges)
 
     def __repr__(self):
         return f'<Group: {self.name}>'
@@ -79,15 +81,17 @@ GroupMember = db.Table('group_member', db.Model.metadata,
     db.Column('gid', db.Integer, db.ForeignKey('group.id')),
     db.Column('uid', db.Integer, db.ForeignKey('member.id')))
 
-
-# Many-to-many relationship for privileges granted to groups
+# GroupPrivilege: A list of privileges for groups, materialized as a table
 class GroupPrivilege(db.Model):
     __tablename__ = 'group_privilege'
     id = db.Column(db.Integer, primary_key=True)
 
-    gid = db.Column(db.Integer, db.ForeignKey('group.id'))
+    group_id = db.Column(db.Integer, db.ForeignKey('group.id'))
+    group = db.relationship('Group', backref='privileges',
+        foreign_keys=group_id)
+
     priv = db.Column(db.String(64))
 
     def __init__(self, group, priv):
-        self.gid = group.id
+        self.group = group
         self.priv = priv

app/models/user.py

@@ -210,10 +210,10 @@ class Member(User):
         """Check whether the member has the specified privilege."""
         if priv in self.special_privs:
             return True
-        return db.session.query(Group, GroupPrivilege).filter(
-            Group.id.in_([g.id for g in self.groups]),
-            GroupPrivilege.gid==Group.id,
-            GroupPrivilege.priv==priv).first() is not None
+        for g in self.groups:
+            if priv in g.privs():
+                return True
+        return False
 
     def special_privileges(self):
         """List member's special privileges."""

master.py

@@ -78,11 +78,11 @@ def update_groups():
         # Update an existing group
         if g is not None:
             changes = (g.css != css) or (g.description != descr) or \
-                (set(g.privs()) != set(privs))
+                (set(g.privs) != set(privs))
             g.css = css
             g.description = descr
 
-            for gpriv in GroupPrivilege.query.filter_by(gid=g.id):
+            for gpriv in g.privs:
                 db.session.delete(gpriv)
             for priv in privs:
                 db.session.add(GroupPrivilege(g, priv))

migrations/versions/fcf53f1a14e3_relate_groups_with_their_privileges_.py

@@ -0,0 +1,25 @@
+"""relate groups with their privileges through a relationship
+
+Revision ID: fcf53f1a14e3
+Revises: 44fbbb1fd537
+Create Date: 2022-05-12 19:43:04.436448
+
+"""
+from alembic import op
+import sqlalchemy as sa
+
+
+# revision identifiers, used by Alembic.
+revision = 'fcf53f1a14e3'
+down_revision = '44fbbb1fd537'
+branch_labels = None
+depends_on = None
+
+
+def upgrade():
+    # Actually modified by hand for once - Lephe'
+    op.alter_column('group_privilege', 'gid', new_column_name='group_id')
+
+
+def downgrade():
+    op.alter_column('group_privilege', 'group_id', new_column_name='gid')