How to get port of docker-compose from env_file?
The env_file
optin will only set environment variables in the docker container itself. Not on the host which is used during the compose 'build'.
To define your port as env var you should use the .env
file as described here
In your case create a .env
file which contains::
PORT=5000
and the docker-compose.yml
:
version: '3'
services:
flask:
build:
context: ./flask
dockerfile: Dockerfile_flask
ports:
#- "5000:5000"
- "${PORT}:${PORT}" # I want to set port defined in the env file
volumes:
- ./logs:/app/flask/log
restart: always
If you want to add environment variable to your container using a env_file you can add it again.
To make it fully clear this example:
A postgres started in compose. The environment variables in the my-env-file
are known inside the container, the env var inside .env
is used during the docker-compose up
process.
a .env
file with:
PORT=5432
a my-env-file
with:
POSTGRES_USER=dev
POSTGRES_PASSWORD=secret
POSTGRES_DB=db
and the docker-compose.yml
:
version: ‘3.3’
services:
postgres:
image: postgres:9.6
container_name: postgres
env_file:
- my-env-file
ports:
- ${PORT}:${PORT}
Wilson
Updated on June 15, 2022Comments
-
Wilson almost 2 years
I want to use port number defined in env file, is it possible? The below is the content of my docker-compose.yml:
version: '3' services: flask: build: context: ./flask dockerfile: Dockerfile_flask env_file: - env_file.env ports: #- "5000:5000" - "${PORT}:${PORT}" # I want to set port defined in the env file volumes: - ./logs:/app/flask/log restart: always
And this is the content of env_file.env
PORT=5000
But some errors raised:
WARNING: The PORT variable is not set. Defaulting to a blank string. ERROR: The Compose file './docker-compose.yml' is invalid because: services.flask.ports is invalid: Invalid port ":", should be [[remote_ip:]remote_port[-remote_port]:]port[/protocol]
If it's possible, how should I do it? Thanks
@lvthillo, thanks for your previous response. But I have another problem that the port can't be accessed in my flask app. The codes are listed as below
import os from flask import Flask application = Flask(__name__) print(os.getenv("PORT")) # this is None my_port = int(os.getenv("PORT", 5000)) # so my_port here is 5000, but I want it to be 5002 defined in .env @application.route("/api/test", methods=['POST']) def index(): print('hello') if __name__ == "__main__": application.run(host="0.0.0.0", port=my_port)
Because the flask app need to run with the same port as the container. Is there any way that I can set the port in env file for both docker-compose and my flask app? Thanks
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Wilson over 5 yearsthanks for response, It did work. But I just found that the port can't be accessed in my flask app. Because I want my flask to run with the same port. Is there any way that I can set the port for both docker-compose and my flask app? Thanks
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lvthillo over 5 years@Wilson please accept the answer if it was correct. Hm I don't fully understand your question but maybe this will help you: it's a basic flask app running in docker and it's running on a different port than 5000: github.com/lvthillo/python-flask-docker
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Avner Moshkovitz over 4 years@Willson, I have excatly the same problem. How did you end up setting the port inside flask to match the port that is set in Docker?