Docker Network Example

Project Setup Instructions

Prerequisites

• Python 3.10.12 installed
• Flask 3.0.3 installed (already added in requirements.txt)

Step-by-Step Guide

1. Clone the Repository:

   git clone https://github.com/rakeshbasnet/docker-network-example.git
   cd docker-network-example
   

2. Copy .env.example File to Create .env File:

   cp .env.example .env
   

3. Set Up Virtual Environment:

   python -m venv venv
   source venv/bin/activate   # On Windows: venv\Scripts\activate
   

4. Install Dependencies:

   pip install -r requirements.txt
   
   

5. Run the Development Server:

   python main.py
   

6. Access the Application: Open a browser and go to: http://127.0.0.1:5000

Docker Network and Docker containers

Prerequisites

• Docker installed

Step-by-Step Guide

1. Build Application Docker Image from Dockerfile:

   docker build -t image-name:tag-name .    //replace your flask-app-image-name and tag name
   

2. Create Docker Network:

   docker network ls  // to list all the networks in docker
   docker network create flask-app-network     //create new network
   

3. Run PostgreSQL DB Container:

   docker run --rm -d \
   --name db \
   --env-file .env \
   -p 5433:5432 \
   --network flask-app-network \
   postgres:13
   

4. Run pgAdmin Container:

   docker run --rm -d \
   --name pgadmin \
   -e PGADMIN_DEFAULT_EMAIL=admin@admin.com \
   -e PGADMIN_DEFAULT_PASSWORD=admin \
   -p 8080:80 \
   --network flask-app-network \
   dpage/pgadmin4:latest
   

5. Create Redis Container:

   docker run --rm -d \
   --name redis \
   --network flask-app-network \
   redis:latest
   

6. Create Flask App Container:

   docker run --rm -d \
   --name flask-app \
   --env-file .env \
   -p 5000:5000 \
   --network flask-app-network \
   image-name:tag-name  //replace your flask-app-image-name and tag name
   

Accessing Application:

1. Before Accessing the Application, Access pgAdmin in http://localhost:8080.
2. Login using the credential passed during container creation.
3. On right top, right click Servers, Click Create->Server Group and Save.
4. Right Click on recently created Server, Click Register->Server-> Connection Tab, Add Postgres Credentials and Connect. If Connection is successful, the docker network is working. Note: For host section in Connection tab, add the db container name and other credentials passed via env files.
5. Look for mydb inside Server and add users table with some data.
6. Now, Access the Flask Application in http://localhost:5000
7. To make sure it is correctly connected with db: Check URL: http://localhost:5000/users, a list of users will retun.
8. To check whether, it is correctly connected with redis cache server, Check URL: http://localhost:5000/cache, it will return a message: Cache Hit: b'Hello from Redis Cache!'