Override Dockerfile ARG from docker-compose.yml - docker

Question

I can't override the Dockerfile arg from docker-compose.yml when I set a default value at Dockerfile arg.
If the user just run de Dockerfile whiteout any parameter I want that docker don't break and at docker-compose.yml I want to set a better architecture.
This is my Dockerfile:
FROM python:3.6 as flask_api
LABEL maintainer 'https://about.me/leandro.garcias'
ARG DEBUG=False
# BD Config
ARG DATABASE_URL='sqlite:///data/app.db'
# Max register per page, when you try to get all
ARG MAX_PER_PAGE=25
# Collect log errors. https://sentry.io
ARG COLLECT_LOG_ERRORS=False
ARG SENTRY_DSN=''
RUN adduser api
USER api
WORKDIR /home/api
COPY requirements.txt manage.py contrib/boot.sh ./
COPY tests tests
COPY app app
RUN mkdir data
ENV PYTHONUNBUFFERED 1
ENV DEBUG $DEBUG
ENV DATABASE_URL $DATABASE_URL
ENV MAX_PER_PAGE $MAX_PER_PAGE
ENV COLLECT_LOG_ERRORS $COLLECT_LOG_ERRORS
ENV SENTRY_DSN $SENTRY_DSN
RUN python -m venv venv
RUN venv/bin/pip install -r requirements.txt
CMD bash boot.sh
EXPOSE 5000:5000
This is my docker-compose.yml:
version: '3'
volumes:
local_data:
data:
networks:
web:
app:
db:
services:
frontend:
image: nginx:1.13
volumes:
- ./contrib/nginx.conf:/etc/nginx/conf.d/default.conf
ports:
- 80:80
networks:
- web
- app
depends_on:
- app
app:
image: flask_api
restart: always
volumes:
- local_data:/home/api/data
networks:
- app
- db
depends_on:
- db
build:
context: .
args:
- DEBUG = False
# BD Config
- DATABASE_URL = postgres://postgres:#db:5432/people
# Max register per page, when you try to get all
- MAX_PER_PAGE = 25
# Collect log errors. https://sentry.io
- COLLECT_LOG_ERRORS = False
- SENTRY_DSN = ''
db:
image: postgres:9.6
volumes:
- data:/var/lib/postgresql/data
networks:
- db
environment:
- POSTGRES_DB=people
I need help ...

Answer 1

I found a solution! Just need to set environment values. :-)
app:
image: flask_api
environment:
- DEBUG=False
# BD Config
- DATABASE_URL=postgres://postgres:#db:5432/people
# Max register per page, when you try to get all
- MAX_PER_PAGE=25
# Collect log errors. https://sentry.io
- COLLECT_LOG_ERRORS=False
- SENTRY_DSN=''

Answer 2

Update 2022
ERROR: environment variable name 'DEBUG ' may not contain whitespace.
This might be the error you're getting. There shouldn't be spaces around the env. variable.
If we are passing args to the build from docker-compose, it would override the default arg value specified in Dockerfile.