#GCP - Storage/Datastore/PubSub image resizing app demo

This is an introductory demo that shows how to leverage GCP services and cloud best practices (decoupling, high availability, Disaster Recovery, Scalability) to create a web application.

This demo has a SOA design, using PHP for the frontend and Python in the backend. The demo web app allows users to fill out a short form with Name, Email, and Picture. The picture is resized, and another page shows the resized picture of all users. The idea is to simulate a social media app, but the concepts can be applied to other examples.

The app has 3 main services:

Front End: hosting the main page, and ingesting the form from users Back End: transforming the picture into thumbnail size Render: displaying all users' thumbnail pictures

Intended app setup, logic, and flow:

• Global Load Balancer

  • 3 backends
    • frontend
    • render
    • bucket with thumbnail pictures (CDN enabled)

• Multi Regional GCS bucket

• Front End

  • 1 or more Instance Groups (in different regions)
  • PHP + GCP APIs (Storage and PubSub)
  • Allows users to upload picture
  • Upload picture into a temp folder in GCS bucket
  • Sends a message to a PubSub topic
    • message content: GCS object location, name, email

• Back End:

  • 1 or more Instance Groups (in different regions)
  • Python + GCP APIs (Storage, PubSub, Datastore)
  • Subscribe to the PubSub topic, reads the message
  • download temp picture, resizes, uploads to GCS bucket
  • create an entry in Datastore:
    • email (as the index); name; thumbnail url; data uploaded (important for rendering later)
  • if everything suceeds .... acknoledge the message (removing from the PubSub topic, to avoid message to be processed again)

• Render:

  • 1 or more Instance Groups (in different regions)
  • PHP + GCP API (Datastore)
  • Queries Data store, sort entities by the newest (so we can display the newest picture 1st)
  • creates an array in PHP, loop, and display

Highlights/Teachble points:

• GCP Global Networking, LB is Global, one single IP (High Availability)
• Due to global networking, we can have VMs running our services in multiple regions (High Availability / DR / Scalability)
• PubSub (Decoupling)
• Datastore (Decoupling / Scalability)
• Storage (High Availability / DR)
• GCE with Autoscaling, Templates (Scalability / Repeatable)

NOTE: I am not and do not claim to be a web developer, or a developer at all. The demo serves its purpose of proving a few points. Feedback is more than welcome, but do it in a nicer and non-derrogatory way. I'd love to incorporate feedback and have a more robust and elegant looking app.