CODEWITHSUNDEEP
pythonpostgresqldockerdocker-compose
rmznbyk 1
rmznbyk 1

Reputation: 1206

Python exits with code 0 immediatelly after stand up with docker

I am trying to prepare a docker-compose file that stands up 2 containers. They are postgres and python app inside an alpine image. Just consider before reading ı need to use python inside alpine.

My Dockerfile is:

FROM python:3

WORKDIR /usr/src/app

COPY requirements.txt ./
RUN pip install --no-cache-dir -r requirements.txt

COPY . .

CMD [ "python", "./app.py" ]

My app.py file:

import psycopg2
from config import config

def connect():
    """ Connect to the PostgreSQL database server """
    conn = None
    try:
        # read connection parameters
        params = config()

        # connect to the PostgreSQL server
        print('Connecting to the PostgreSQL database...')
        conn = psycopg2.connect(**params)

        # create a cursor
        cur = conn.cursor()

 # execute a statement
        print('PostgreSQL database version:')
        cur.execute ("SELECT * FROM my_table;")

        # display the PostgreSQL database server version
        db_version = cur.fetchone()
        print(db_version)

     # close the communication with the PostgreSQL
        cur.close()
    except (Exception, psycopg2.DatabaseError) as error:
        print(error)
    finally:
        if conn is not None:
            conn.close()
            print('Database connection closed.')


if __name__ == '__main__':
    connect()

I started python container with that command:

docker run -it my_image app.py

I seperately started 2 container(postgres and python) and make it worked. However my container works only once and its job is to make an select job inside postgresql database.

That was first part. My main goal is below.

For the simplicity i prepared a docker-compose.yml file:

version: '3'

services:

  python:
    image: python
    build:
        context: .
        dockerfile: Dockerfile

  postgres:
    image: postgres:${TAG:-latest}
    build:
      context: .
    environment:
      POSTGRES_PASSWORD: example
    ports:
      - "5435:5432"
    networks:
      - postgres

networks:
  postgres:

My dockerfile is here

When i type docker-compose up my postgres starts but python exits with code 0.

my_file_python_1 exited with code 0

What should i do for stands alone container for python apps with docker-compose? It always works only once. I can make it work constantly with

docker run -d -it my_image app.py

But my goal is to make it with docker-compose.

Upvotes: 0

Views: 4917

Answers (1)

Ashok Reddy
Ashok Reddy

Reputation: 1085

version: '3'

services:

  python:
    image: python
    build:
        context: .
        dockerfile: Dockerfile

  postgres:
    image: postgres:${TAG:-latest}
    build:
      context: .
    environment:
      POSTGRES_PASSWORD: example
    ports:
      - "5435:5432"
    networks:
      - postgres

networks:
  postgres:
     tty: true

If exit code is 0 means container exited after all execution, means you have to run the process in foreground to keep container running. if exit code is other than 0, means it is exiting because of code issue. so try to run any foreground process.

Could you check if enabling the tty option (see reference) in your docker-compose.yml file the container keeps running?

Upvotes: 1

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