SQLAlchemy recovery after a rollback "This transaction is inactive"

Question

I’m trying to recover after a primary key violation in an insert, by logging the duplicate user to another table. However, my code produces the error InvalidRequestError: This transaction is inactive.

Unfortunately the traceback doesn’t show the specific line within this function where the error occurs–it only goes as deep as the function calling this function (which is strange).

Does my try/except begin/rollback/commit pattern look correct?

def convert_email(db, user_id, response):
    """Map a submitted email address to a user, if the user
    does not yet have an email address.
    """
    email = response['text_response']
    trans = db.begin()
    try:
        update_stmt = users_tbl.update(
                and_(users_tbl.c.user_id==user_id,
                     users_tbl.c.email==None))
        db.execute(update_stmt.values(dict(email=email)))
        trans.commit()
    except sqlalchemy.exc.IntegrityError as e:
        trans.rollback()
        if e.orig.pgcode == UNIQUE_VIOLATION:
            trans = db.begin()
            try:
                user = db.execute(users_tbl.select(users_tbl.c.email==email))
                parent_user_id = user.first()['user_id']

                insert_stmt = duplicate_public_users_tbl.insert().values(
                        user_id=user_id,
                        parent_id=parent_user_id)
                db.execute(insert_stmt)
                trans.commit()
            except sqlalchemy.exc.IntegrityError as e:
                trans.rollback()
                if e.orig.pgcode != UNIQUE_VIOLATION:
                    raise

Asked By: skyler

||

Source

Answer 1

The exception was being produced by the calling function, which itself was wrapped in a transaction.

with engine.begin() as db:
    convert_email(db, user_id, response)

The inner rollback() call must terminate the outer transaction as well. This is hinted at by the documentation for Transaction.close(),

… This is used to cancel a Transaction without affecting the scope of an enclosing transaction.

Answered By: skyler

SQLAlchemy recovery after a rollback "This transaction is inactive"

Question:

Answers: