SimpleTools

Collection of classes which helps to organize code, increase readability and maintainability.

Installation

Add this line to your application's Gemfile:

gem 'simple_tools', source: 'https://github.com/isidzukuri/simple_tools'

And then execute:

$ bundle

Or install it yourself as:

$ gem install simple_tools

Usage

• Operation
• Pub/Sub (Events)

Operation

Inspired by trailblaizer operation.

Idea is to put complex task(operation) in class, split it into commands(steps) and invoke each step one by one.

class BasicOperation < SimpleTools::Operation
  step :command_one
  step :command_two

  def command_one
    p 'run some code'
    update_context(:first_var, params[:some_value])
  end

  def command_two
    context[:first_var]
    p 'run other code'
  end
end

Example of calling operation:

=> result = BasicOperation.call(some_value: 100)
# 'run some code'
# 'run other code'
=> result.success?
# true
=> result.context[:first_var]
# 100

SimpleTools::Operation respond to .call and can receive hash of parameters. To share variables between steps inside operation use update_context(:any_key, 'any value') setter and context[:any_key] getter.

.call returns object which respond to .success? and returns boolean value.

Also .context method is available. It returns set by operation values.

Next steps will not be invoked and current call of operation is considered as failed if error occurs on any of previuos steps

class FailedOperation < SimpleTools::Operation
  step :command_one
  step :command_with_error
  step :command_three

  def command_one
    p '1'
  end

  def command_with_error
    p '2'
    error!(:name, 'not valid message')
    # or for multiple errors:
    errors!({name: ['one more error', 'and another error']})
    p '2.1'
  end

  def command_three
    # will not run because :command_with_error has failed
    p '3'
  end
end

error!, errors! - add new item(s) to list of errors. It do not raise exception and dont break execution of current method.

Example of calling failed operation:

=> result = FailedOperation.call
# 1
# 2
# 2.1
=> result.success?
# false
=> result.errors
# {name: ['error description', 'one more error', 'and another error']}

---

Pub/Sub

Publish/subscribe messaging, or pub/sub messaging, is a form of service-to-service communication. In a pub/sub model, any message published to a topic is immediately received by all of the subscribers to the topic. Pub/sub messaging can be used to enable event-driven architectures, or to decouple applications in order to increase performance, reliability and scalability.

Implement subscriber which will be waiting for event:

class NewSubscriber < SimpleTools::Events::Subscriber
  def handle
    p 'notification about event received!'
    p event_name
    p payload
  end
end

payload, event_name methods are available in instance of SimpleTools::Events::Subscriber.

Subscribe to event by name:

SimpleTools::Events.subscribe('some_event_name', NewSubscriber)

Publish event:

SimpleTools::Events.publish('some_event_name')

Output example:

"notification about event received!"
"some_event_name"
nil

Or publish event with payload if required:

payload = {
  id: 11,
  type: 'description of type',
  some_values: [1,2,3]
}

SimpleTools::Events.publish('some_event_name', payload)

Output example:

"notification about event received!"
"some_event_name"
{:id=>11, :type=>"description of type", :some_values=>[1, 2, 3]}

---

Development

After checking out the repo, run bin/setup to install dependencies. 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/isidzukuri/simple_tools.