Strum::Esb

Useful sender RabbitMQ messages and handle them

Installation

Add this line to your application's Gemfile:

gem 'strum-esb'

And then execute:

$ bundle install

Or install it yourself as:

$ gem install strum-esb

Usage

Configuration

Exchanges can be customized by each message type:

Strum::Esb.config.info_exchange = `demo.info`
Strum::Esb.config.event_exchange = `demo.events`
Strum::Esb.config.action_exchange = `demo.actions`
Strum::Esb.config.notice_exchange = `demo.notice`

Before publish hooks allow you to configure custom code that will be able to modify properties of the message that will be published or execute any arbitrary logic

Strum::Esb.config.before_publish_hooks << ->(body, properties) { properties[:correlation_id] = "hello world" }

Before handler hooks allow you to inspect raw data before any processing has strated:

Strum::Esb.config.before_handler_hooks << ->(deserialized_msg, delivery_info, metadata) do 
  puts "We don't even know if msg is valid JSON, this is some text from RabbitMQ"
  puts deserialized_msg
end

After handler hook allows you to have insight on how handler was executed:

Strum::Esb.config.after_handler_hooks << ->(deserialized_msg, delivery_info, metadata, payload, error) do 
  puts "Message was deserialized succesfully" if payload
  puts "Error occured" if error
end

Sending message:

Strum::Esb::Action.call(`payload`, `action`, `resource`)

Strum::Esb::Event.success(`payload`, `resource`, `*events`)
Strum::Esb::Event.failure(`payload`, `resource`, `*events`)

Strum::Esb::Info.call(`payload`, `resource`)

Strum::Esb::Notice.call(`payload`, `notice`)
Strum::Esb::Notice.call(`payload`, `notice`, `resource`)

Handling message:

require "strum/esb"

module Queues
  class Resource
    include Strum::Esb::Handler

    from_queue "resource-queue",
               bindings: {
                 events: %w[user/create user/update],

               }

    def handler(payload)
      # code here ...
    end
  end
end

Sending protobuf via strum-esb

1. Encode your protobuf message using encode method to send it.
2. Define protobuf_service in your handler, and disable json:

require "strum/esb"
require "contracts/test_pb"

module Queues
  class Resource
    include Strum::Esb::Handler

    enable_json          false
    enable_protobuf      true
    use_protobuf_service Test::Router::Service
    from_queue "resource-queue",
               bindings: {
                 events: %w[user/create user/update],

               }

    def handler(payload)
      # code here ...
    end
  end
end

Your rpc action must have the same name as your method in queue class, for example: if method is action_get_user, rpc action needs to be ActionGetUser.

1. Pass content type as additional param when you send Strum::Esb message:

   message = { id: 10 }
   args = {
   content_type: "application/x-protobuf",
   message_class: Messages::ActionGetUser
   }
   Strum::Esb::Action.call(message, "action", "resource", **args)
   

2. Configure proto serialization/deserialization:

   Strum::Esb.config.serializer_conf = {
   to_proto: proc do |message_class, payload|
             ::CustomSerializer.to_protobuf(message_class, payload).to_proto
           end,
   from_proto: proc do |message_class, encoded_payload|
               rpc_instance = message_class.decode(encoded_payload)
               ::CustomSerializer.from_protobuf(rpc_instance)
             end
   }
   

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://code.qpard.com/srtrum/strum-esb.