Add SchedulerAgent, which periodically runs other agents.

app/models/agents/scheduler_agent.rb

@@ -0,0 +1,89 @@
+require 'rufus-scheduler'
+
+module Agents
+  class SchedulerAgent < Agent
+    cannot_be_scheduled!
+    cannot_receive_events!
+    cannot_create_events!
+    can_run_other_agents!
+
+    description <<-MD
+      This agent periodically triggers a run of each target Agent according to a user-defined schedule.
+
+      Select target Agents and set a cron-style schedule to `schedule`.
+      In the traditional cron format, a schedule part consists of these five columns: `minute hour day-of-month month day-of-week`.
+
+      * `0 22 * * 1-5`: every day of the week at 22:00 (10pm)
+
+      In this variant, you can also specify seconds:
+
+      * `30 0 22 * * 1-5`: every day of the week at 22:00:30
+
+      And timezones:
+
+      * `0 22 * * 1-5 Europe/Paris`: every day of the week when it's 22:00 in Paris
+
+      * `0 22 * * 1-5 Etc/GMT+2`: every day of the week when it's 22:00 in GMT+2
+
+      There's also a way to specify "last day of month":
+
+      * `0 22 L * *`: every month on the last day at 22:00
+
+      And "monthdays":
+
+      * `0 22 * * sun#1,sun#2`: every first and second sunday of the month, at 22:00
+
+      * `0 22 * * sun#L1`: every last sunday of the month, at 22:00
+    MD
+
+    def default_options
+      { 'schedule' => '0 * * * *' }
+    end
+
+    def working?
+      true
+    end
+
+    def check!
+      targets.active.each { |target|
+        log "Agent run queued for '#{target.name}'"
+        Agent.async_check(target.id)
+      }
+    end
+
+    def validate_options
+      if (spec = options['schedule']).present?
+        begin
+          Rufus::Scheduler::CronLine.new(spec)
+        rescue ArgumentError
+          errors.add(:base, "invalid schedule")
+        end
+      else
+        errors.add(:base, "schedule is missing")
+      end
+    end
+
+    before_save do
+      self.memory.delete('scheduled_at') if self.options_changed?
+    end
+
+    def scheduler_tag
+      '%s#%d' % [self.class.name, id]
+    end
+
+    class << self
+      def scheduler_tag_to_id(tag)
+        case tag
+        when /\A#{Regexp.quote(self.name)}\#(\d+)\z/o
+          $1.to_i
+        end
+      end
+
+      def from_scheduler_tag(tag)
+        if id = scheduler_tag_to_id
+          find_by(id: id)
+        end
+      end
+    end
+  end
+end

app/views/agents/_form.html.erb

@@ -40,6 +40,20 @@
             </div>
           </div>
 
+          <div class="schedule-region" data-can-be-scheduled="<%= @agent.can_be_scheduled? %>">
+            <div class="can-be-scheduled">
+              <div class="form-group">
+                <%= f.label :runners %>
+                <span class="glyphicon glyphicon-question-sign hover-help" data-content="Other than the system-defined schedule above, this agent may be run by user-defined ScheduleAgents."></span>
+                <% eventRunners = current_user.agents.select(&:can_run_other_agents?) %>
+                <%= f.select(:runner_ids,
+                               options_for_select(eventRunners.map {|s| [s.name, s.id] },
+                                                  @agent.runner_ids),
+                               {}, { multiple: true, size: 5, class: 'select2 form-control' }) %>
+              </div>
+            </div>
+          </div>
+
           <div class="chain-region" data-can-run-other-agents="<%= @agent.can_run_other_agents? %>">
             <div class="can-run-other-agents">
               <div class="form-group">

app/views/agents/_table.html.erb

@@ -25,7 +25,7 @@
         </td>
         <td class='<%= "agent-disabled" if agent.disabled? %>'>
           <% if agent.can_be_scheduled? %>
-            <%= agent.schedule.to_s.humanize.titleize %>
+            <%= agent_schedule(agent, ',<br/>') %>
           <% else %>
             <span class='not-applicable'></span>
           <% end %>

app/views/agents/show.html.erb

@@ -72,7 +72,7 @@
             <% if @agent.can_be_scheduled? %>
               <p>
                 <b>Schedule:</b>
-                <%= (@agent.schedule || "n/a").humanize.titleize %>
+                <%= agent_schedule(@agent) %>
               </p>
 
               <p>

lib/huginn_scheduler.rb

@@ -1,5 +1,87 @@
 require 'rufus/scheduler'
 
+class Rufus::Scheduler
+  SCHEDULER_AGENT_TAG = Agents::SchedulerAgent.name
+
+  class Job
+    # Extract an ID of SchedulerAgent if a matching tag is found.
+    def scheduler_agent_id
+      tags.each { |tag|
+        if agent_id = Agents::SchedulerAgent.scheduler_tag_to_id(tag)
+          return agent_id
+        end
+      }
+    end
+
+    # Return a SchedulerAgent tied to this job.  Return nil if it is
+    # not found or disabled.
+    def scheduler_agent
+      agent_id = scheduler_agent_id or return nil
+
+      Agent.of_type(Agents::SchedulerAgent).active.find_by(id: agent_id)
+    end
+  end
+
+  # Get all jobs tied to any SchedulerAgent
+  def scheduler_agent_jobs
+    jobs(tag: SCHEDULER_AGENT_TAG)
+  end
+
+  # Get a job tied to a given SchedulerAgent
+  def scheduler_agent_job(agent)
+    jobs(tags: [SCHEDULER_AGENT_TAG, agent.scheduler_tag]).first
+  end
+
+  # Schedule or reschedule a job for a given SchedulerAgent and return
+  # the running job.  Return nil if unscheduled.
+  def schedule_scheduler_agent(agent)
+    job = scheduler_agent_job(agent)
+
+    if agent.disabled?
+      if job
+        puts "Unscheduling SchedulerAgent##{agent.id} (disabled)"
+        job.unschedule
+      end
+      nil
+    else
+      if job
+        return job if agent.memory['scheduled_at'] == job.scheduled_at.to_i
+        puts "Rescheduling SchedulerAgent##{agent.id}"
+        job.unschedule
+      else
+        puts "Scheduling SchedulerAgent##{agent.id}"
+      end
+
+      job = schedule_cron agent.options['schedule'], tags: [SCHEDULER_AGENT_TAG, agent.scheduler_tag] do |job|
+        if scheduler_agent = job.scheduler_agent
+          scheduler_agent.check!
+        else
+          puts "Unscheduling SchedulerAgent##{job.scheduler_agent_id} (disabled or deleted)"
+          job.unschedule
+        end
+      end
+
+      agent.memory['scheduled_at'] = job.scheduled_at.to_i
+      agent.save
+
+      job
+    end
+  end
+
+  # Schedule or reschedule jobs for all SchedulerAgents and unschedule
+  # orphaned jobs if any.
+  def schedule_scheduler_agents
+    scheduled_jobs = Agent.of_type(Agents::SchedulerAgent).map { |scheduler_agent|
+      schedule_scheduler_agent(scheduler_agent)
+    }.compact
+
+    (scheduler_agent_jobs - scheduled_jobs).each { |job|
+      puts "Unscheduling SchedulerAgent##{job.scheduler_agent_id} (orphaned)"
+      job.unschedule
+    }
+  end
+end
+
 class HuginnScheduler
   attr_accessor :mutex
 
@@ -82,6 +164,12 @@ class HuginnScheduler
       end
     end
 
+    # Schedule Scheduler Agents
+
+    @rufus_scheduler.every '1m' do
+      @rufus_scheduler.schedule_scheduler_agents
+    end
+
     @rufus_scheduler.join
   end
 end

spec/models/agents/scheduler_agent_spec.rb

@@ -0,0 +1,54 @@
+require 'spec_helper'
+
+describe Agents::SchedulerAgent do
+  before do
+    @agent = Agents::SchedulerAgent.new(name: 'Example', options: { 'schedule' => '0 * * * *' })
+    @agent.user = users(:bob)
+  end
+
+  describe "validation" do
+    it "should validate schedule" do
+      @agent.should be_valid
+
+      @agent.options.delete('schedule')
+      @agent.should_not be_valid
+
+      @agent.options['schedule'] = nil
+      @agent.should_not be_valid
+
+      @agent.options['schedule'] = ''
+      @agent.should_not be_valid
+
+      @agent.options['schedule'] = '0'
+      @agent.should_not be_valid
+
+      @agent.options['schedule'] = '*/15 * * * * * *'
+      @agent.should_not be_valid
+
+      @agent.options['schedule'] = '*/15 * * * * *'
+      @agent.should be_valid
+
+      @agent.options['schedule'] = '*/1 * * * *'
+      @agent.should be_valid
+
+      @agent.options['schedule'] = '*/1 * * *'
+      @agent.should_not be_valid
+    end
+  end
+
+  describe "check!" do
+    it "should run targets" do
+      targets = [agents(:bob_website_agent), agents(:bob_weather_agent)]
+      @agent.targets = targets
+      @agent.save!
+
+      target_ids = targets.map(&:id)
+      stub(Agent).async_check(anything) { |id|
+        target_ids.delete(id)
+      }
+
+      @agent.check!
+      target_ids.should be_empty
+    end
+  end
+end