Docker-compose build error with django and mysql

Question

I trying to build a Django project with docker-compose and MySQL, but when i run the "docker

db uses an image, skipping
Building with native build. Learn about native build in Compose here:
Building web
Sending build context to Docker daemon  22.02kB
Step 6/6 : COPY . /code/
 ---> 2f42d48fb668
Successfully built 2f42d48fb668
Successfully tagged djangonew_web:latest
Traceback (most recent call last):
  File "docker-compose", line 3, in <module>
  File "compose/cli/main.py", line 80, in main
  File "compose/cli/main.py", line 192, in perform_command
  File "compose/metrics/decorator.py", line 18, in wrapper
  File "compose/cli/main.py", line 369, in build
  File "compose/project.py", line 521, in build
  File "compose/project.py", line 503, in build_service
  File "compose/service.py", line 1131, in build
  File "compose/progress_stream.py", line 22, in stream_output
  File "compose/utils.py", line 50, in split_buffer
  File "compose/utils.py", line 26, in stream_as_text
  File "compose/service.py", line 1894, in build
FileNotFoundError: [Errno 2] No such file or directory: '/tmp/tmpjwyh07ql'
[16684] Failed to execute script docker-compose

My Dockerfile:

FROM python:3
ENV PYTHONBUFFERD=1
WORKDIR /code
COPY requirements.txt /code/
RUN pip install -r requirements.txt
COPY . /code/

My docker-compose.yml file:

version: "3.9"

services:
  db:
    image: mysql
    environment:
      - MYSQL_DB=mysql_test
      - MYSQL_USER=test
      - MYSQL_PASSWORD=test
      - MYSQL_ROOT_PASSWORD=test
  web:
    build: .
    command: python manage.py runserver 0.0.0.0:8000
    volumes:
      - .:/code
    ports:
      - "8000:8000" 
    depends_on:
      - db

This is such a cryptic error that i don't really now where to go. If someone can help me i would be very happy.

Thank you !

Answer 1

Avoid copying using an all encompassing pattern like . (the dot) for copying the whole working directory.

For one, this will be different for every environment where this runs because it includes all hidden and local files, and not only those you expect (those that are tracked by your version system, eg).

Second, there might be links that point to other directories, so you might even end up copying a lot of stuff you definitely never wanted to have in your Dockerfile. Which is most probably what happens in your case.

.dockerignore is a way to work against copying too much, but you should also try to copy more explicitly. This will also help others to understand what you want to achieve with this specific COPY command in your Dockerfile.

tl;dr: the resulting docker image should contain only what it needs to run, and should have to change (contain anything different) only if the change is intentional.