Watchdogagent

app/models/agents/watchdog_agent.rb

@@ -0,0 +1,67 @@
+module Agents
+  class WatchdogAgent < Agent
+
+    description <<-MD
+      A WatchdogAgent emits an event if it did not receive an event for a given amount of time.
+      `timespan` can be something like `10m` (10 minutes), `9.7h` (9.7 hours) or `18d` (18 days).
+      If `emit_once` is set to `false`, it will emit one event for each scheduled run, until it
+      receives an event again. If it is set to `true`, it will only emit one event.
+      In `message` you can give a message that will be part of the emitted event.
+    MD
+
+    event_description <<-MD
+      Events look like this:
+
+          { "message": "Your message" }
+    MD
+
+    default_schedule "8pm"
+
+    def validate_options
+      log options['timespan']
+      unless options['timespan'].present? && ('mhd'.include? options['timespan'][-1]) && options['timespan'][0..-2].to_f > 0
+        errors.add(:base, "timespan is required and has to be a positive number followed by 'm', 'h' or 'd'")
+      end
+      errors.add(:base, "message is required") unless options['message'].present?
+    end
+
+    def default_options
+      {
+        'timespan' => "5.2d",
+        'message' => "Nothing happened in the last 5.2 days!",
+        'emit_once' => "true"
+      }
+    end
+
+    def working?
+      !recent_error_logs?
+    end
+
+    def check
+      unless options['emit_once'].to_s == 'true' && !received_after_last_emit?
+        timeout = (options['timespan'][0..-2].to_f * (case options['timespan'][-1]
+          when 'm' then 60
+          when 'h' then (60 * 60)
+          when 'd' then (60 * 60 * 25)
+          else 1
+        end)).seconds.ago
+        if last_receive_at < timeout
+          received_after_last_emit false
+          create_event :payload => {'message' => options['message'] }
+        end
+      end
+    end
+
+    def receive(events)
+      received_after_last_emit true
+    end
+
+    def received_after_last_emit?
+      memory['received after last emit'].to_s == 'true'
+    end
+
+    def received_after_last_emit(value)
+      memory['received after last emit'] = (value.to_s == 'true')
+    end
+  end
+end