Objective

Have one server sending HTTP requests to two services, using protocol buffers as the exchanged messages.

This also serves as a proof of concept as we can achieve polymorphic types with protobuf.

INDEX

• How it works
• How to use this
• Requirements
• Install

How it works

• v2_requests_router.rb receives a GET request.
• Based on this request, a message is sent to either PDF service or Finalize service

About the message generated

• Generated with a protocol buffer
• This message has a field named payload
• This is a polymorphic field of type either FinalizeInvoice or GeneratePDF

PDF Service and Finalize Service

• Both are listening for a POST
• Both decode the message, encoded as a protocol buffer
• Both display the message received on the console using puts

Requirements

• Protobuf. check installation guide
• Ruby (this was tested with version 2.4)
• Bundler

Install

bundle install

How to generate ruby classes from .proto files

• Move to protos folder cd protos
• Generate classes protoc --ruby_out=./ *.proto
  • this command compiles all the files named *.proto as ruby files, and saves the ruby files in the --ruby_out path

How to use this

• open 3 consoles
• ruby v2_requests_router.rb
• ruby pdf_service.rb
• ruby finalize_service.rb
• Example of request to finalize invoices
  • curl -X GET 'http://localhost:4567/finalize-invoices?invoice_ids[]=124124,62322'
• Example of request to generate PDF
  • curl -X GET 'http://localhost:4567/generate-pdfs?invoice_ids[]=234335,222222'