StepMachine

step_machine is a simple gem for executing code based in steps. Each step can be validated and if a step fails, the execution is aborted.

Installation

Add this line to your application's Gemfile:

gem 'step_machine'

or 

gem 'step_machine', git: git@bitbucket.org:geisonbiazus/step_machine.git

And then execute:

$ bundle

Usage

Creating and running steps:

include StepMachine

step(:step_1) do
    # code for step 1
end

step(:step_2) do
    # code for step 2
end

run_steps

This code will run the steps in the created order

Changing the execution order

step(:step_1).next_step = step(:step_2)

or:

step(:step_1).next_step do
    step(:step_2)
end

Validating steps

step(:step_1).validate do |step|
    step.result == "OK"
end

step(step_1).validate(/^OK/)

step(step_1).validate('OK')

Validating steps error message

step(:step_1).validate do |step|
    step.result == "OK"
    step.errors << 'This is a array error message forced to false validate'
end

step(step_1).errors({}) << 'This is a hash error message forced to false validate'

step(step_1).errors('') << 'This is a string error message forced to false validate'

Callbacks

on_step_failure do |f|
    f.go_to :step_2     
end

on_step_failure :only => [:step_2] do |f|
    f.restart
end

on_step_failure :except => [:step_1] do |f|
    if contition
        f.repeat
    else
        f.continue
    end
end

before_each_step do |step|
    # code
end

after_each_step do |step|
    # code
end

Executing code if a step runs successful

step(:step_1).success do |step|
    # code
end

Conditional Steps

step(:step_1).condition do 
    true
end

Executing a step depending on other step condition

step(:step_2) do
    # code
end.condition do 
    step(:step_1).performed?
end

Grouping steps

group :group_1 do

    step :step_1 do
        #code
    end

    step :step_2 do
        #code
    end

end

step :step_3 do
    #code
end

run_steps( {:group => :group_1} ) # only the steps 1 and 2 will be performed

Group with condition

group(:group_1)

    step(:step_2) do
        # code
    end

end.condition do 
        step(:step_1).performed?
end

run_steps # only if was performed

Execute from and/or upto defined step

step :step_1 { ... }
step :step_2 { ... }
step :step_3 { ... }
step :step_4 { ... }
run_steps :upto => :step_2                   # should execute :step_1 end :step_2
run_steps :from => :step_3                   # should execute :step_3 end :step_4
run_steps :from => :step2, :upto => :step_3  # should execute :step_2 end :step_3

Contributing

1. Fork it
2. Create your feature branch (git checkout -b my-new-feature)
3. Commit your changes (git commit -am 'Add some feature')
4. Push to the branch (git push origin my-new-feature)
5. Create new Pull Request