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”:

I get the following error:

  File “”, line 6, in <module>
engine = create_engine(os.getenv(“DATABASE_URL”))
File “/usr/local/lib/python3.6/dist-packages/sqlalchemy/engine/”, line 435, in create_engine
return strategy.create(*args, **kwargs)
File “/usr/local/lib/python3.6/dist-packages/sqlalchemy/engine/”, 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

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