Class: OpenWFE::CronExpression

Inherits:
TimeExpression show all
Defined in:
lib/openwfe/expressions/fe_cron.rb

Overview

Scheduling subprocesses for repeating execution

<cron tab="0 9-17 * * mon-fri" name="//reminder">
    <send-reminder/>
</cron>

In this short process definition snippet, the subprocess “send-reminder” will get triggered once per hour (minute 0) from 0900 to 1700 and this, from monday to friday.

The ‘name’ of the cron indicates also at which level the cron should be bound. A double slash means the cron is bound at engine level (and will continue until it is unbound, as long as the engine is up, if the engine is a persisted one, the cron will continue when the engine restarts).

It’s possible to specify ‘every’ instead of ‘tab’ :

cron :every => "10m3s" do
    send_reminder
end

The subprocess ‘send_reminder’ will thus be triggered every ten minutes and three seconds.

Instance Attribute Summary collapse

Attributes inherited from TimeExpression

#applied_workitem, #scheduler_job_id, #scheduler_tags

Attributes inherited from FlowExpression

#apply_time, #attributes, #children, #environment_id, #fei, #parent_id, #raw_representation

Attributes included from Contextual

#application_context

Instance Method Summary collapse

Methods inherited from TimeExpression

#cancel, #unschedule

Methods inherited from FlowExpression

#cancel, #clean_children, #delete_variable, #dup_environment, #fetch_environment, #fetch_text_content, #get_binding, #get_environment, #get_parent, #get_root_environment, #has_attribute, #initialize, is_definition, is_definition?, #lookup_attribute, #lookup_attributes, #lookup_boolean_attribute, #lookup_comma_list_attribute, #lookup_downcase_attribute, #lookup_ref, #lookup_string_attribute, #lookup_sym_attribute, #lookup_value, #lookup_variable, #lookup_vf_attribute, names, #new_environment, new_exp, #owns_its_environment?, #paused?, #remove_child, #reply_to_parent, #set_variable, #store_itself, #synchronize, #to_s, #to_yaml_properties

Methods included from Contextual

#get_work_directory, #init_service, #lookup

Methods included from Logging

#ldebug, #ldebug_callstack, #lerror, #lfatal, #linfo, #llog, #lunknown, #lwarn

Methods included from OwfeServiceLocator

#get_engine, #get_error_journal, #get_expool, #get_expression_map, #get_expression_pool, #get_expression_storage, #get_expression_storages, #get_journal, #get_participant_map, #get_scheduler, #get_wfid_generator

Methods inherited from ObjectWithMeta

#class_def, meta_def, meta_eval, metaclass

Constructor Details

This class inherits a constructor from OpenWFE::FlowExpression

Instance Attribute Details

#counter ⇒ Object

Returns the value of attribute counter.



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# File 'lib/openwfe/expressions/fe_cron.rb', line 76

def counter
  @counter
end

#every ⇒ Object

Returns the value of attribute every.



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# File 'lib/openwfe/expressions/fe_cron.rb', line 76

def every
  @every
end

#name ⇒ Object

Returns the value of attribute name.



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# File 'lib/openwfe/expressions/fe_cron.rb', line 76

def name
  @name
end

#raw_child ⇒ Object

Returns the value of attribute raw_child.



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# File 'lib/openwfe/expressions/fe_cron.rb', line 76

def raw_child
  @raw_child
end

#tab ⇒ Object

Returns the value of attribute tab.



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# File 'lib/openwfe/expressions/fe_cron.rb', line 76

def tab
  @tab
end

Instance Method Details

#apply(workitem) ⇒ Object 



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# File 'lib/openwfe/expressions/fe_cron.rb', line 80

def apply (workitem)

    return reply_to_parent(workitem) \
        if @children.size < 1

    @counter = 0

    @applied_workitem = workitem.dup
    @applied_workitem.flow_expression_id = nil

    @tab = lookup_attribute(:tab, workitem)
    @every = lookup_attribute(:every, workitem)

    @name = lookup_attribute(:name, workitem)
    @name = fei.to_s unless @name

    @raw_child, _fei = get_expression_pool.fetch(@children[0])
    @raw_child.parent_id = nil

    clean_children

    @children = nil

    determine_scheduler_tags

    #
    # schedule self
    
    reschedule get_scheduler

    #
    # store self as a variable
    # (have to do it after the reschedule, so that the schedule
    # info is stored within the variable)

    set_variable @name, self

    #
    # resume flow
    
    reply_to_parent workitem
end

#reply(workitem) ⇒ Object 



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# File 'lib/openwfe/expressions/fe_cron.rb', line 123

def reply (workitem)
    # discard silently... should never get called though
end

#reschedule(scheduler) ⇒ Object

This method is called at the first schedule of this expression or each time the engine is restarted and this expression has to be rescheduled.



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# File 'lib/openwfe/expressions/fe_cron.rb', line 167

def reschedule (scheduler)

    #return unless @applied_workitem

    @scheduler_job_id = if @name[0, 2] == "//"
        @name
    else
        "#{@fei.wfid}__#{@scheduler_job_id}"
    end

    if @tab
        get_scheduler.schedule(
            @tab, 
            { 
                :schedulable => self, 
                :job_id => @scheduler_job_id,
                :tags => @scheduler_tags })
    else
        get_scheduler.schedule_every(
            @every, 
            { 
                :schedulable => self, 
                :job_id => @scheduler_job_id,
                :tags => @scheduler_tags })
    end

    ldebug { "reschedule() name is   '#{@name}'" }
    ldebug { "reschedule() job id is '#{@scheduler_job_id}'" }

    #store_itself
        #
        # done by the containing environment itself
end

#trigger(params) ⇒ Object

This is the method called each time the scheduler triggers this cron. The contained segment of process will get executed.



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# File 'lib/openwfe/expressions/fe_cron.rb', line 132

def trigger (params)

    ldebug { "trigger() cron : #{@fei.to_debug_s}" }

    @raw_child.application_context = @application_context

    begin

        get_expression_pool.launch_template(
            @fei.wfid, nil, @counter, @raw_child, @applied_workitem.dup)

        #
        # update count and store self

        @counter += 1

        if @name[0, 2] == '//'
            set_variable @name, self
        else
            store_itself
        end

    rescue
        lerror do 
            "trigger() cron caught exception\n"+
            OpenWFE::exception_to_s($!)
        end
    end
end