NatsListener

Maintainability Test Coverage

Installation

Add this line to your application's Gemfile:

gem 'nats_listener'

And then execute:

$ bundle

Or install it yourself as:

$ gem install nats_listener

Usage

For usage in your project we offer:

  1. Create initializer.rb or manually call NatsListener.current.establish_connection(service_name: [YOUR SERVICE NAME], servers: [NATS_SERVERS_URLS])
  2. For publishing you can use NatsListener.current.publish serializing message with two strategies(protobuf and json). Json strategy is proposed in https://github.com/beastia/nats_listener. Protobuf strategy is included into https://github.com/beastia/nats_streaming_listener.
  3. For receiving messages we offer subscribers

Protobuf strategy

2.3.3 :006 > require 'nats_streaming_listener'
=> true
2.3.3 :006 > m = NatsStreaming::NatsMessage.new(sender_service_name: 'ololo', receiver_action_name: 'ololo1', receiver_action_parameters:[1,2,3].map(&:to_s), message_timestamp: Time.now.utc.to_i, transaction_id: 'unique')
 => #<NatsListener::NatsMessage sender_service_name="ololo" receiver_action_name="ololo1" receiver_action_parameters=["1", "2", "3"] message_timestamp=1538902717 transaction_id="unique"> 
2.3.3 :007 > m.serialize
 => "\n\x05ololo\x12\x06ololo1\x1A\x011\x1A\x012\x1A\x013 \xBD\x95\xE7\xDD\x05*\x06unique"

Json strategy

2.3.3 :009 > m = NatsListener::Message.new({action: 'ololo'})
 => #<NatsListener::Message:0x007ff1869a3628 @message={:publisher=>nil, :timestamp=>2018-10-07 09:00:29 UTC, :message_id=>"7dfc4de9-d920-4cc1-8cfe-5e85f7fb855d", :data=>{:action=>"ololo"}}> 
2.3.3 :010 > m.to_json
 => "{\"publisher\":service1,\"timestamp\":\"2018-10-07T09:00:29.133Z\",\"message_id\":\"7dfc4de9-d920-4cc1-8cfe-5e85f7fb855d\",\"data\":{\"action\":\"ololo\"}}"

Creating client

NatsListener::Client.current = NatsListener::Client.new(
  logger: Ougai::Logger.new(STDOUT),
  skip: false,
  catch_errors: true,
  catch_provider: Rollbar
)

All arguments are optional. logger - logger that you can pass to application. It will be called to debug messages. skip - skip calls. Useful for tests catch_errors - catch errors, log them and pass to catch_provider catch_provider - provider that is called when error occurs, e.g. Rollbar.

Subscribers

For using subscribers we offer one quite simple way:

  1. Create subscribers folder.
  2. Create your own subscriber derived from NatsListener::Subscriber
  3. Load and subscribe all subscribers, e.g. ruby NatsListener::Client.current = NatsListener::Client.new( logger: Ougai::Logger.new(STDOUT), skip: false, catch_errors: true, catch_provider: Rollbar ) NatsListener::Client.current.establish_connection(service_name: [YOUR SERVICE NAME], servers: [NATS_SERVERS_URLS]) path = Rails.root.join('app', 'subscribers', '*.rb') Dir.glob(path) do |entry| entry.split('/').last.split('.').first.camelize.constantize.new.subscribe end
  4. ???
  5. PROFIT

NB!

Right now nats functionality is proved to work aside of Puma workers because of the conflicts between puma and nats-pure gems.

TODO:

  1. Add nats-streaming subscribers
  2. Add usage of nats-streaming for calls

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://github.com/beastia/nats_listener. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The gem is available as open source under the terms of the MIT License.

Code of Conduct

Everyone interacting in the NatsListener project’s codebases, issue trackers, chat rooms and mailing lists is expected to follow the code of conduct.