How to use FastAPI for microservices in Python

In this lesson we are going to learn How to use FastAPI for microservices in Python, so first of all what is Microservices, Microservices is an architectural style of building software applications as a collection of small, independent, and loosely coupled services. each service is responsible for a specific business capability and communicates with other services through well-defined APIs. This approach allows for greater scalability, flexibility, and maintainability compared to traditional monolithic architectures.

The key characteristics of microservices are:

Decentralized governance: Each service is owned by small and autonomous team that is responsible for its development and maintenance.
Decentralized data management: Each service manages its own data and communicates with other services through APIs.
Automated deployment: Services can be deployed independently of each other, allowing for faster and more frequent releases.

Resilience: Services are designed to be fault tolerant and can continue to operate even if other services are unavailable.
Loosely coupled: Services communicate with each other through APIs, allowing them to evolve independently of each other.
Language and technology agnostic: Services can be built using different programming languages and technologies, as long as they can communicate through a common API.

Using microservices can bring many benefits to the development and operation of software systems, such as scalability, flexibility and easier maintenance, but also it brings some challenges such as service discovery, monitoring and debugging, security and data consistency.

This is basic example of FastAPI for microservices in Python, FastAPI is modern and fast web framework for building APIs with Python 3.6+ based on standard Python type hints. It is easy to use, and it is designed to be easy to understand and use, and it is optimized for performance.

Install FastAPI and its dependencies

pip install fastapi
pip install uvicorn

1 2	pip install fastapi pip install uvicorn

Create a new file called main.py

from fastapi import FastAPI

app = FastAPI()

@app.get("/")
def read_root():
    return {"Hello": "World"}

@app.get("/items/{item_id}")
def read_item(item_id: int, q: str = None):
    return {"item_id": item_id, "q": q}

from fastapi import FastAPI

app = FastAPI()

@app.get("/")

def read_root():

return {"Hello": "World"}

@app.get("/items/{item_id}")

def read_item(item_id: int, q: str = None):

return {"item_id": item_id, "q": q}

Run the service

uvicorn main:app --reload

1	uvicorn main:app --reload

Test the service with the following command

curl http://localhost:8000/
curl http://localhost:8000/items/42?q=test

1 2	curl http://localhost:8000/ curl http://localhost:8000/items/42?q=test

This is simple example of how to use FastAPI to create microservice. in this example we defined two routes, / and /items/{item_id}, which return JSON response. we can add more routes and functionality as needed for our microservice.

FastAPI has builtin support for type hints and validation, and it also provides a simple and easy-to-use dependency injection system. Additionally, it provides support for OAuth2 and JWT, it also supports WebSocket, which is useful for building real-time applications.

You can find more detailed documentation on how to use FastAPI on the official website https://fastapi.tiangolo.com/ and more examples on the GitHub page https://github.com/tiangolo/fastapi