Deploying Stateless Microservices: Introduction
Creating a Simple Stateless Microservice
In this section, we will create a simple stateless microservice using Flask, a lightweight web framework for Python. The microservice is a basic to-do application that allows users to add and retrieve tasks using an exposed REST API.
When using Python, a best practice is to create a virtual environment for each project to avoid changing the global Python environment needed by Linux or other applications. We are going to use virtualenvwrapper to create a new isolated environment for our project.
mkvirtualenv stateless-flask
Create the folders for our Flask application and install its dependencies.
# Create the project structure
mkdir -p stateless-flask
cd stateless-flask
# The app folder will contain the Flask application
mkdir -p app
# The kubernetes folder will contain Kubernetes manifests
mkdir -p kubernetes
# Install Flask
pip install Flask==3.0.3
# Add some dependencies to requirements.txt
cat << EOF > app/requirements.txt
blinker
click
Flask==3.0.3
importlib_metadata
itsdangerous
Jinja2
MarkupSafe
Werkzeug
zipp
EOF
The following Python code creates our simple Flask application. Use the heredoc syntax to create the file app/app.py.
cat << EOF > app/app.py
from flask import Flask, jsonify, request
app = Flask(__name__)
# Define a list of tasks
tasks = []
# route for getting all tasks
@app.route('/tasks', methods=['GET'])
def get_tasks():
# Return the list of tasks as a JSON response
return jsonify({'tasks': tasks})
# Route for getting a single task
@app.route('/tasks', methods=['POST'])
def add_task():
# Create a new task from the request data
task = {
'id': len(tasks) + 1,
'title': request.json['title'],
'description': request.json['description'],
}
# Add the new task to the list of tasks
tasks.append(task)
# Return the new task as a JSON response
return jsonify(task), 201
if __name__ == '__main__':
app.run(
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