Module: Sqewer::SimpleJob

Defined in:
lib/sqewer/simple_job.rb

Overview

A module that you can include into your Job class. It adds the following features:

  • initialize() will have keyword access to all accessors, and will ensure you have called each one of them
  • to_h() will produce a symbolized Hash with all the properties defined using attr_accessor, and the job_class_name
  • inspect() will provide a sensible default string representation for logging

This module validates if the attributes defined in the job class are the same as those persisted in the queue. More details on Sqewer::SimpleJob#initialize. Because of this, it's required to create a new job class when adding or removing an attribute. This mechanism guarantees strong consistency. Without it, a new deployed job class could process old incompatible payloads.

Constant Summary collapse

UnknownJobAttribute = 
Class.new(Sqewer::Error)
MissingAttribute = 
Class.new(Sqewer::Error)
EQ_END = 
/(\w+)(\=)$/

Instance Method Summary collapse

Instance Method Details

#initialize(**jobargs) ⇒ Object

Initializes a new Job with the given job args. Will check for presence of accessor methods for each of the arguments, and call them with the arguments given.

If one of the accessors was not triggered during the call, an exception will be raised (because you most likely forgot a parameter for a job, or the job class changed whereas the queue still contains jobs in old formats).

Parameters:

  • jobargs (Hash) —

    the keyword arguments, mapping 1 to 1 to the accessors of the job



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# File 'lib/sqewer/simple_job.rb', line 55

def initialize(**jobargs)
  @simple_job_args = jobargs.keys
  touched_attributes = Set.new
  jobargs.each do |(k,v)|

    accessor = "#{k}="
    touched_attributes << k
    unless respond_to?(accessor)
      raise UnknownJobAttribute, "Unknown attribute #{k.inspect} for #{self.class}"
    end

    send("#{k}=", v)
  end

  accessors = methods.grep(EQ_END).map{|method_name| method_name.to_s.gsub(EQ_END, '\1').to_sym }
  settable_attributes = Set.new(accessors)
  missing_attributes = settable_attributes - touched_attributes

  missing_attributes.each do | attr |
    raise MissingAttribute, "Missing job attribute #{attr.inspect}"
  end
end

#inspect ⇒ String

Returns the inspection string with the job and all of it's instantiation keyword attributes. If inspectable_attributes has been overridden, the attributes returned by that method will be the ones returned in the inspection string.

j = SomeJob.new(retries: 4, param: 'a')
j.inspect #=> "<SomeJob:{retries: 4, param: \"a\"}>"

Returns:

  • (String) —

    the object inspect string



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# File 'lib/sqewer/simple_job.rb', line 38

def inspect
  key_attrs = inspectable_attributes
  hash_repr = to_h
  h = key_attrs.each_with_object({}) do |k, o|
    o[k] = hash_repr[k]
  end
  "<#{self.class}:#{h.inspect}>"
end

#inspectable_attributes ⇒ Array<Symbol>

Returns the list of methods on the object that have corresponding accessors. This is then used by #inspect to compose a list of the job parameters, formatted as an inspected Hash.

Returns:

  • (Array<Symbol>) —

    the array of attributes to show via inspect



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# File 'lib/sqewer/simple_job.rb', line 25

def inspectable_attributes
  # All the attributes that have accessors
  methods.grep(EQ_END).map{|e| e.to_s.gsub(EQ_END, '\1')}.map(&:to_sym)
end

#to_h ⇒ Object 



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# File 'lib/sqewer/simple_job.rb', line 78

def to_h
  keys_and_values = @simple_job_args.each_with_object({}) do |k, h|
    h[k] = send(k)
  end

  keys_and_values
end