Getting Started With Fast API and Docker

FASTAPI

What is fastAPI

FastAPI is a modern, fast (high-performance), web framework for building APIs with Python 3.6+ based on standard Python type hints to validate, serialize, and deserialize data, and automatically auto-generate OpenAPI documents.

Why fastAPI

FastAPI has is one of the latest python api's for web development. It has some of this features:

1. It is indeed fast

It is fast when we compare it to other major Python frameworks like Flask and Django.

2. Support for asynchronous code

This is one of exciting feature of FastAPI that it supports asynchronous code out of the box using the async/await Python keywords.

3. Very short development time

It takes like 8 lines of code to comeup with a hello, word program

4. Easy testing

It has a feature of test driven development with the help using the TestClient provided by fastAPI.

5. Excellent documentation

It has one of the easiest documentation that one can understand.

6. Easy deployment

You can easily deploy your FastAPI app via Docker using FastAPI provided docker image

Requirements

Python 3.6+

Installation of fastapi on windows.

pip install fastapi

Installation on Mac and Linux

pip3 install fastapi uvicorn

Example

First create a folder at your own location of choice

mkdir foldername && cd foldername

create a virtual environment inside the folder you created

python3 -m venv env

activate the virtual environment created called env

source env/bin/activate

Create a python file with the following code and save as myapp.py

from fastapi import FastAPI, Depends

app = FastAPI()

@app.get('/')
async def root():
    return {'message': 'Hello World!'}

Then to run the server, we use the following command:

 uvicorn myapp:app --reload

To know it it works with no error, you will see this in your commandline

INFO:     Uvicorn running on http://127.0.0.1:8000 (Press CTRL+C to quit)
INFO:     Started reloader process [84109] using statreload
INFO:     Started server process [84111]
INFO:     Waiting for application startup.
INFO:     Application startup complete.

Now to open in browser, use the following link

http://127.0.0.1:8000/docs

you will see the following output

before going to docker, we can create a requirement.txt file that has all the tools that you have installed in one place by running;

pip3 freeze > requirement.txt

DOCKER

Docker is an open source platform for building ,deploying and managing containerized applications.
Docker container is a virtualized runtime environment that provides isolation capabilities for separating the execution of applications from the underpinning system

Why docker

speed - docker has both execution speed,startuo speed and operational speed.
consistency - Build an image once and use it any where. The same image that is used to run the tests is used in production. This avoids the works in my machine problems.
Flexibility - Containers are portable. Well to an extent (as long as the host is running some form of linux or linux vm).

Building a docker image

Create a docker file and save with this commands

FROM python:3.9

WORKDIR /code

COPY ./requirements.txt ./requirements.txt

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

COPY ./app 

CMD ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "80"]

Then build your image

docker build -t myimage ./