Fortune Speak

Fortune Speak is a Python sample app for Managed VMs that synthesize and display a random fortune sound everytime you load the page.

Demo

It extends a traditional Python App Engine application with new functionalities that are unlocked by Managed VMs

• Get more CPU and RAM by running your App Engine module on Google Compute Engine VMs
  • set GCE machine type in app.yaml (view sources)
• Escape the sandbox by writing to files and launching subprocess
  • cache wave file to local disk (view sources)
  • launch the fortune executable (view sources)
• Customize your runtime by installing third party packages
  • install the fortune package with apt-get (view sources)
  • install pyttsx and flask from requirements.txt with pip (view sources)
• Call into native Python C extensions
  • import and call _speak pyttsx driver (view sources)

Below is a tutorial that will guide you on how to build, run and deploy this application step by step.

Prerequisites

During this step you will

• create a new Managed VMs project
• provision your local development environments
• run the final application locally and deploy it to production

Create your project

1. Go to Google Developers Console and create a new project.
2. Enable billing
3. Open https://preview.appengine.google.com/settings?&app_id=s~<project>
4. Click Setup Google APIs project for VM Runtime...

Setup Docker

1. Install boot2docker

   • MacOSX instructions
   • Windows instructions
   • Linux releases

2. Setup and start boot2docker

    boot2docker init
    boot2docker up
   

Setup the Cloud SDK

1. Get and install the SDK preview release
2. Setup the Managed VMs components: gcloud components update appengine-managed-vms gcloud auth login gcloud set project docker pull gcr.io/google_appengine/python-compat

Run the application locally

1. Get the application code

    git clone https://github.com/GoogleCloudPlatform/appengine-vm-fortunespeak-python
    cd appengine-vm-fortunespeak-python
    git fetch --all
   

2. Run the application locally

    gcloud preview app run .
   

3. After seeing a request to /_ah/start in the logs open http://localhost:8080

Deploy the application to your project

1. Build and deploy the application image

    gcloud preview app deploy . --server preview.appengine.google.com
   

2. After the command complete succesfully open https://<project>.appspot.com

Hello World!

During this step you will:

• create a simple Python hello world application

0. First switch to step0 branch

    git checkout step0
   

1. Create a app.yaml file w/ the default App Engine configuration

2. Create a main.py file using webapp2 w/ a RequestHandler that print hello: <Country the HTTP request is coming from>

3. Run locally and deploy it to production.

Solution

• Review the solution

• Compare with your working directory

    git diff step1 -R
  

• If stuck, stash your working directory and switch to the solution branch

    git stash
    git checkout step1
  

Hello Managed VMs

During this step you will:

• enable Managed VMs in your application configuration
• select a bigger instance class

1. Modify app.yaml to add vm: true
2. Modify app.yaml to select a bigger instance class
3. Run locally
4. Notice that a Dockerfile has been created in your application directory
5. Deploy to production

Solution

• Review the solution

• Compare with your working directory

    git diff step2 -R
  

• If stuck, stash your working directory and switch to the solution branch

    git stash
    git checkout step2
  

Escape the sandbox

During this step you will:

• perform system operation: write to the local filesystem

1. Modify main.py to log the greetings to a file called 'messages.txt'
2. Modify main.py to add a new RequestHandler that display the content of this file.
3. Run locally and deploy it to production

Solution

• Review the solution

• Compare with your working directory

    git diff step3 -R
  

• If stuck, stash your working directory and switch to the solution branch

    git stash
    git checkout step3
  

Customize the Runtime Environment

During this step you will:

• add native dependencies to your application with apt-get
• perform system operattion: launch an external process

1. Modify Dockerfile to RUN apt-get install -y fortunes
2. Modify main.py to launch /usr/games/fortunes with the subprocess module in the main RequestHandler, capture the standard output and display it back in the response.
3. Run it locally and deploy to production

Solution

• Review the solution

• Compare with your working directory

    git diff step4 -R
  

• If stuck, stash your working directory and switch to the solution branch

    git stash
    git checkout step4
  

Manage Python dependencies

During this step you will:

• managed your application dependencies with pip and requirements.txt
• rewrite your web application handler using a modern python framework Flask

1. Create a requirements.txt with Flask listed as a dependency
2. Modify Dockerfile to RUN pip install -r requirements.txt -t .
3. Edit main.py to use flask.route instead of webapp2.RequestHandler
4. Run it locally and deploy to production

Solution

• Review the solution

• Compare with your working directory

    git diff step5 -R
  

• If stuck, stash your working directory and switch to the solution branch

    git stash
    git checkout step5
  

Use Python C extensions

During this step you will:

• add pyttsx C extensions as a dependency of your application
• call into native code to perform text to speech.

1. Modify requirements.txt to list pyttsx as a depdency

2. Copy the file synth.py from the master branch

    git checkout master synth.py
   

3. Call synth.Say from you main request handler and return the wavform data with the audio-x/wav content type

4. Run it locally and deploy to production

Solution

• Review the solution

• Compare with your working directory

    git diff step6 -R
  

• If stuck, stash your working directory and switch to the solution branch

    git stash
    git checkout step6