Linking python app docker and postgress docker

I have two docker containers running by the following commands:

docker run --name postgres -v "/Users/xxx/Desktop/Coding/DockerMounting":/home/ -e POSTGRES_PASSWORD=xyz -d postgres
docker run -it -v "/Users/xxx/Desktop/Coding/DockerMounting":/home/t -p 5000:5000 --name some-app --link postgres:postgres -d xxx/ubuntu:latest

I have created the necessary user, database and table in my postgres (psql) container.

I am trying to run a python script:

import os
from sqlalchemy import create_engine

from sqlalchemy.orm import scoped_session, sessionmaker
engine = create_engine(os.getenv(“DATABASE_URL”))

db = scoped_session(sessionmaker(bind=engine))
def main():

flights = db.execute(“SELECT origin, destination, duration FROM flights”).fetchall()

for flight in flights:

print(f"{flight.origin} to {flight.destination}, {flight.duration} minutes.")
if name == “main”:

main()

I get the following error:

  File “list.py”, line 6, in <module>

engine = create_engine(os.getenv(“DATABASE_URL”))

File “/usr/local/lib/python3.6/dist-packages/sqlalchemy/engine/init.py”, line 435, in create_engine

return strategy.create(*args, **kwargs)

File “/usr/local/lib/python3.6/dist-packages/sqlalchemy/engine/strategies.py”, line 56, in create

plugins = u._instantiate_plugins(kwargs)

I know one issue is that I need to set DATABASE_URL env - but I am not sure what should be that value

#python #docker #postgresql