Docker postgres

Question

Have a problem with docker-. I writing Django project with Postgres as a database and want to dockerize it. So the problem: when I build&up containers there are an exceptions:

...
polls       |   Is the server running on host "postgres" (172.19.0.2) and accepting
polls       |   TCP/IP connections on port 5432?

But if I do it the second time - all is OK and a server is started.

Dockerfile:

FROM python:3
ENV PYTHONUNBUFFERED 1

RUN mkdir /code
WORKDIR /code

ADD requirements.txt /code/
RUN pip install --upgrade pip
RUN pip install -r requirements.txt
ADD . /code/

docker-compose.yml:

version: '3'

services:
  postgres:
    image: postgres:latest
    container_name: polls_db
    env_file:
      - ./src/main/.env
    volumes:
      - ./postgres/docker-entrypoint-initdb.d:/docker-entrypoint-initdb.d

  polls:
    build: .
    container_name: polls

    volumes:
      - .:/code
    env_file:
      - ./src/main/.env
    ports:
      - "8000:8000"
    depends_on:
      - postgres
    command: bash -c "python src/manage.py migrate && python src/manage.py runserver 0.0.0.0:8000"

Take a look at this: stackoverflow.com/questions/51659972/… — Danila Kiver
– Danila Kiver, Commented Aug 13, 2018 at 19:04
If this is not your case, please explain in details, which commands produce the error, where and how they are being run, and which commands do not produce errors; similarly - when and how they are being run. — Danila Kiver
– Danila Kiver, Commented Aug 13, 2018 at 19:06
It sounds to me like the first time you try to launch the application container, the database just hasn’t started up yet, but by the second time you try, it has. IME it can take about a minute especially for the first container launch. — David Maze
– David Maze, Commented Aug 13, 2018 at 19:18

bluescores · Accepted Answer · 2018-08-13 20:18:16Z

Like David Maze said in the comments, it sounds like your db just isn't quite ready for action between starting the postgres container and the db actually being ready to take new connections. You've set your polls service to immediately start migrations as well, which means it expects the db to be available the second it starts running.

Docker has some suggestions for this. Basically, write a wrapper script to use as your entry point, something like:

#!/bin/bash

count=1
until [ $count -eq 5 ]
  do
     sleep 3
     python src/manage.py migrate && break
     count=$((count + 1))
  done

 if [ $count -lt 5 ]; then
  python src/manage.py runserver 0.0.0.0:8000
 fi

Some bash wizard is probably going to find something wrong with this script because I didn't test it (feel free to comment) :) The idea being, try to run migrations a few times before giving up. You could also use a quicker test via psql/curl/wget, I chose to use manage.py migrate since those aforementioned tools are often not installed on stock Docker images.

Collectives™ on Stack Overflow

Docker postgres

1 Answer 1

Comments

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Linked

Related