Breaking in Google App Engine25 Jun 2016
Google Cloud Platform is Google’s solution to cloud hosting. Initially it was released as Google App Engine back in 2008, but Google found that developers weren’t flocking to their platform as anticipated due to how different Google was doing things. In 2011 Google Cloud Platform was launched which included Google App Engine and Google Cloud Storage. As the years progressed Google had to create solutions that matched how developers were working today, this is where other products such as Google Cloud Engine came along.
This post is specifically on Google App Engine, and goes over deploying a simple web application from scratch.
First you will need to create a new project by going to console.cloud.google.com. After logging in click the accordion at the top left and select IAM & Admin. From hear select “Create Project” and give your project a name.
After the project has been created click the accordion again in the top left and select “Development”. Make sure that “Source Code” is selected along the left, and then select “Get started” on the pop-up in the middle. In this walkthrough I opt for “Automatically mirror from GitHub or Bitbucket” and provide Google with access to my private bitbucket repository.
At this point I recommend following the linked instructions to set up Google Cloud’s SDK at cloud.google.com/sdk/. You will also need to install the Python libraries with
gcloud components install app-engine-python, along with the python SDK at cloud.google.com/appengine/downloads.
Creating the app
You’ll want to first clone your code onto your local machine. For me the command was similar to
git clone https://firstname.lastname@example.org/user/gcp-demo-app.git gcp-demo-app.
Inside of the cloned repository you will need to make an
app.yaml file that defines the runtime environment for your application. An example configuration for a basic flask app looks like the following:
runtime: python27 api_version: 1 threadsafe: true # [START handlers] handlers: - url: /.* script: gcp.app # [END handlers]
This should all be pretty straight forward, for a full reference if you don’t understand anything check out their documentation.
Next we’ll need to create a
gcp.py file to house our
app callable like we referenced in the
app.yaml file. Using Flask a simple example looks as follows:
from flask import Flask app = Flask(__name__) @app.route("/") def hello(): return "Hello World!"
Google is smart enough to do
app.run() for us, and so that is omitted.
Since Flask isn’t in the standard library for Python this adds some small complications, Google App Engine requires that any imported libraries exist in our applications folder.
gcp.py to look like the following at the top:
from google.appengine.ext import vendor # Add any libraries installed in the "lib" folder. vendor.add('lib') <...>
Let’s also create a
requirements.txt file and add the following to it:
Now Google App Engine knows to look inside of the
lib folder relative to our applications location. Let’s go ahead and install Flask inside of the lib folder like so:
mkdir lib pip install -t lib -r requirements.txt
Testing our work
Before you push the code up to your selected SCM website you can run the application locally to see that everything works. You do this with the Google Cloud SDK by running
dev_appserver.py .. This command runs the application like it will in Google App Engine from your current directory.
If the command starts successfully you should be able to visit your browser at
http://localhost:8080 and see your application running.
Since we’re using SCM this is pretty straight-forward. First push your code up:
git add app.yaml gcp.py lib requirements.txt git commit -m "Initial commit" git push
On the Google Cloud Console you should see your code populate into their website under the “Source Code” section.
Finally run this locally:
appcfg.py -A [YOUR_PROJECT_ID] -V v1 update ./
After the command completes you should see your application deployed at