Deploying FastAPI app with Google Cloud Run

Introduction

This post explains how to deploy a FastAPI app using Google Cloud Run.

Prerequisites

• Google Cloud account
• gcloud CLI
• Docker
• Python

Project setup

Create a FastAPI app using Poetry.

pip install poetry
poetry new sample
cd sample
mv sample app
cd app
poetry add fastapi
poetry add 'uvicorn[standard]'

Create app/main.py

touch app/main.py

Edit main.py as follows

# main.py

from fastapi import FastAPI

app = FastAPI()


@app.get("/", tags=["root"])
async def root():
    return {"message": "Hello World"}

Run it in uvicorn

poetry shell
uvicorn app.main:app --reload

Google Cloud Run setup

If you have already installed gcloud CLI, update it as follows.

gcloud components update

Connect the gcloud CLI to your GCP account.

gcloud auth login

Set up your project ID

gcloud config set project PROJECT_ID

Region settings

gcloud config set run/region REGION

Docker settings

gcloud auth configure-docker

Prepare Dockerfile in the same hierarchy as the app directory.

FROM python:3.11.3
ENV PYTHONUNBUFFERED True

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

ENV APP_HOME /root
WORKDIR $APP_HOME
COPY /app $APP_HOME/app

EXPOSE 8080
CMD ["uvicorn", "app.main:app", "--host", "0.0.0.0", "--port", "8080"]

Prepare requirements.txt file for Dockerfile.
(In this case, use requirements.txt in the Dockerfile.)

poetry export -f requirements.txt --output requirements.txt

Now that it is ready, deploy to Cloud Run.

gcloud run deploy sample --port 8080 --source .

If successful, it will be created with the name sample.
A URL will be created, so check the operation.

Conclusion

With the above, you can now deploy your FastAPI app to Google Cloud Run.

Although the details are omitted here, it would be a good idea to actually add CORS and headers in middleware and implement an authentication function such as Firebase Authentication.

Note: The path to import must be specified from the app directory.

Example: app/lib/test.py

# app/main.py
from app.lib import test