Docker compose file use networks

Sometimes the subnet of docker network will conflict with the current server or AWS server, thus you need to change the subnet. There are two solutions:

You create one network, and add it in the docker-compose file
create a new network directly in the docker-compose file

method 1:

create a new network using docker docker network create -d bridge --subnet=192.168.0.0/16 data-management

then write the docker-compose.yml file as following:

version : '3'

services:
    data_management_backend:
        container_name : data_management_backend
        restart: always

        build: ./backend
        tty: true
        ports:
            - "3103:3003" # thus you can split the production and test environment
        command: python run.py
        volumes:
            - /absolut-path/data-management/backend/temp:/absolut-path/data-management/backend/temp
        networks:
            - data-management

    data_management_frontend:
        container_name: data_management_frontend
        restart: always
        build: ./frontend
        ports:
            - "3104:3004"
        command: npm run dev
        depends_on:
            - data_management_backend
        networks:
            - data-management

networks:
    data-management:
        external:true

method 2:

version : '3'

services:
    data_management_backend:
        container_name : data_management_backend
        restart: always

        build: ./backend
        tty: true
        ports:
            - "3103:3003" # thus you can split the production and test environment
        command: python run.py
        volumes:
            - /absolut-path/data-management/backend/temp:/absolut-path/data-management/backend/temp
        networks:
            - data-management

    data_management_frontend:
        container_name: data_management_frontend
        restart: always
        build: ./frontend
        ports:
            - "3104:3004"
        command: npm run dev
        depends_on:
            - data_management_backend
        networks:
            - data-management

networks:
    data-management:
        ipam:
            config:
                - subnet: 172.177.0.0/16

docker error: http: invalid Host header

This error come from the docker version 20.10.24. We need to upgrade the docker version to the newest.

sudo snap refresh docker --channel=latest/edge

please remeber to change the /var/run/docker.sock file permission.

use docker command without sudo

after you install docker successfully, then do the following steps:

sudo groupadd docker
sudo usermod -aG docker $USER
if you write docker ps and give you error like below:

docker ps Got permission denied while trying to connect to the Docker daemon socket at unix:///var/run/docker.sock: Get “http://%2Fvar%2Frun%2Fdocker.sock/v1.24/containers/json”: dial unix /var/run/docker.sock: connect: permission denied
then you need to change the right of /var/run/docker.sock
ls -l /var/run/docker.sock srw-rw---- 1 root root 0 Jan 29 19:00 /var/run/docker.sock
sudo chmod 666 /var/run/docker.sock
ls -l /var/run/docker.sock
srw-rw-rw- 1 root root 0 Jan 29 19:00 /var/run/docker.sock

You see that the srw-rw---- changed to srw-rw-rw-

now the docker can run correctly.

Use Docker to contain Flask and Ngnix

Here’s the tree structure of the project

.
├── docker-compose.yml
├── flask-app
│   ├── Dockerfile
│   ├── home
│   ├── __init__.py
│   ├── __pycache__
│   ├── requirements.txt
│   ├── run.py
│   ├── static
│   └── templates
└── nginx
    ├── default.conf
    └── Dockerfile

One important thing for the flask is that you should use python run.py in the docker-compose.yml instead of ‘flask run –port 5001’

Here’s the run.py

from flask import Flask
import pathlib
import sys,os

root_path = pathlib.Path(__file__).resolve().parent
home_path = root_path/'home'
sys.path.insert(0, str(home_path))
print(f'root_path is {root_path}')
from routes import blueprint

app = Flask(__name__)

app.register_blueprint(blueprint)

if __name__ == "__main__":
    app.run(host='0.0.0.0', debug=True, port=5002)

Here’s the Dockerfile in the flask-app

FROM python:3.8

WORKDIR usr/src/app

ENV FLASK_ENV=development
ENV FLASK_APP=run.py

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

Here’s the docker-compose.yml file

version : '3'

services:
    flask_app:
        container_name: flask_app
        restart: always

        build: ./flask-app
        tty: true
        # volumes:
        ports:
            - "5002:5002"
        command:  python run.py # this one gives you the server's address and localhost addresss
        # command: flask run --port 5002 # this one is not working. It gives you the address of the localhost not the server's address

    flask_nginx:
        container_name: flask_nginx
        restart: always
        build: ./nginx
        ports:
            - "8085:8085"
        depends_on:
            - flask_app

How to use MongoDB docker container

How to combine Flask, MongoDB and Docker

Create Flask app and using pymongo to access the mongodb data. Here you need to pay attention to the mongodb host address: docker-data:/data/db
Create a Dockerfile in the Flask app folder
Create a Dockerfile for Mongodb
Create a docker-compose.yml file to combine Flask app and Mongodb : persist the mongodb data by docker volume. mount the MongoDB data to the /data/db
Check the mongodb host ip: docker inspect mongodb-docker-container-name and get the IPAddress from the Networks. And use this ip as the MongoDB host address. If the IPAdress cannot work, then use the GateWay address. Or just don’t use the host parameter in MongoClient.
docker-compose up --build -d