Order Processor

In this tutorial, we will run a Go CDK application called Order Processor on a local machine.

Order Processor is a sample application that lets users place orders to convert images to PNG format, and to view the results. The main business logic is written in a cloud-agnostic manner using the generic APIs for blob, pubsub and docstore.

The Order Processor application has two parts: a web frontend, and an image-processing backend called a processor. They communicate over a pubsub topic, store order information in a docstore collection, and store image files in a blob bucket.

Prerequisites🔗

You will need to install the following software for this tutorial:

• Git
• Go

Then you need to clone the Go CDK repository. The repository contains the Order Processor sample.

git clone https://github.com/google/go-cloud.git
cd go-cloud/samples/order

Building🔗

Run the following in the samples/order directory:

go build

Running Locally🔗

If you run order with no arguments, both the frontend and the processor will run together in the same process.

./order

The frontend is now running on http://localhost:10538.

Visit the home page in your browser and click “Convert an Image”.

Enter an email address (it need not be real) and select any image file from your computer. Then click Submit.

Now visit the order list page by returning to the home page and clicking “List Conversions”. It may take a few seconds to process the order (thanks to an artificial delay in the processor), so refresh the page until you see your order in the list.

Then click on the output image link to see the converted image in your browser.

Running on a Cloud Provider🔗

To run the Order Processor application on a cloud provider like Google Cloud Platform, Amazon AWS or Microsoft Azure, you will have to provision some resources:

• A storage bucket, to hold the image files. (See the blob How-To Guide.)
• A Pub/Sub topic and subscription, for requests from the frontend to the processor. (See the pubsub How-To Guide.)
• A document store collection to store order metadata. (See the docstore How-To Guide.)

Then launch the order program with flags that provide the URLs to your resources. Run order -help to see the list of flags.