Mentat

#!/usr/bin/env python3

from flask import Flask

from flask_sqlalchemy import SQLAlchemy

import time

app = Flask(__name__)

app.config['SQLALCHEMY_DATABASE_URI'] = 'postgresql://'

app.config['SQLALCHEMY_TRACK_MODIFICATIONS'] = False

db = SQLAlchemy(app)

def isolated():

    print(db.session.query('NOW()').first()[0])

def main():

    print('Flask-SQLAlchemy session lifetime management test (times in one section should always differ)')

    print('No commit')

    print(db.session.query('NOW()').first()[0])

    time.sleep(1)

    print(db.session.query('NOW()').first()[0])

    print(db.session.query('NOW()').first()[0])

    print()

    print('Isolated context')

    isolated()

    time.sleep(1)

    isolated()

    print()

    print('Commit - simple')

    db.session.commit()

    print(db.session.query('NOW()').first()[0])

    time.sleep(1)

    print(db.session.query('NOW()').first()[0])

    print()

    print('Commit - transaction start')

    db.session.commit()

    print(db.session.query('NOW()').first()[0])

    db.session.commit()

    time.sleep(4)

    print(db.session.query('NOW()').first()[0])

    print()

    print('Rollback')

    db.session.rollback()

    print(db.session.query('NOW()').first()[0])

    db.session.rollback()

    time.sleep(1)

    print(db.session.query('NOW()').first()[0])

    print()

if __name__ == '__main__':

    main()