How to serve REST API on Google Cloud?

Question

I have made a REST API for my Ubuntu machine on Google Cloud. How can I connect this API with public IP address?

In the below code I am uploading image file in multipart/form-data format.

from flask import Flask, url_for, send_from_directory, request
import logging, os
# from werkzeug import secure_filename
import werkzeug
app = Flask(__name__)
file_handler = logging.FileHandler('server.log')
app.logger.addHandler(file_handler)
app.logger.setLevel(logging.INFO)

PROJECT_HOME = os.path.dirname(os.path.realpath(__file__))
UPLOAD_FOLDER = '{}/uploads/'.format(PROJECT_HOME)
app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER


def create_new_folder(local_dir):
    newpath = local_dir
    if not os.path.exists(newpath):
        os.makedirs(newpath)
    return newpath

@app.route('/Classifier01', methods = ['POST'])
def api_upload():


    app.logger.info(PROJECT_HOME)
    if request.method == 'POST':
      app.logger.info(app.config['UPLOAD_FOLDER'])

      #get image and save in ../uploads
      img = request.files['image']
      img_name = werkzeug.secure_filename(img.filename)
      create_new_folder(app.config['UPLOAD_FOLDER'])
      saved_path = os.path.join(app.config['UPLOAD_FOLDER'], img_name)
      app.logger.info("saving {}".format(saved_path))
      img.save(saved_path)

      #do some processing here

      return "I got your image"
    else:
      return "Where is the image?"

if __name__ == '__main__':
    app.run()

It start on 127.0.0.1:5000 how make it on public IP.

score 0 · Answer 1 · answered Feb 26 '20 at 21:12

First, start your app to listen on interface of your VM -> run it like this app.run(host='0.0.0.0')

Then, you have 2 solutions

Use the public IP of your VM to reach it. Don't forget to open the correct firewall rule for this (source IP range= 0.0.0.0/0, port TCP 5000). But it's not perfect. You can update your app for listening on the port 80 for a more standard API port on internet. You can also plug an nginx on your VM. On it, you can also deploy a SSL certificate and allow to reach your service on the port 443 in HTTPS. pff, lot of work
You can use HTTP(s) load balancer for this. SSL in automatically managed. Simply create a backend with your VM (a NEG), your health check and set up your frontend. It's the easiest way!

How to serve REST API on Google Cloud?

1 Answers1