Veto job execution if current trigger state is paused

worker/src/main/scala/com/lucidchart/piezo/WorkerTriggerListener.scala

@@ -1,8 +1,9 @@
 package com.lucidchart.piezo
 
 import com.timgroup.statsd.StatsDClient
+
 import java.util.Properties
-import org.quartz.Trigger.CompletedExecutionInstruction
+import org.quartz.Trigger.{CompletedExecutionInstruction, TriggerState}
 import org.quartz._
 import org.slf4j.LoggerFactory
 
@@ -15,7 +16,20 @@ class WorkerTriggerListener(props: Properties, statsd: StatsDClient, useDatadog:
 
  def getName: String = "WorkerTriggerListener"
 
- def vetoJobExecution(trigger: Trigger, context: JobExecutionContext): Boolean = false
+ def vetoJobExecution(trigger: Trigger, context: JobExecutionContext): Boolean = {
+ // Called right before the job is about to execute on the worker.
+
+ /*
+ Under certain conditions, a job may come up for execution after a trigger
+ has been paused, leading to unexpected additional executions.
+
+ To fix this, right before Quartz starts the job, we check the _current_ trigger
+ state to ensure that job wasn't paused after the execution was queued.
+ */
+
+ // Veto if current trigger state is paused
+ context.getScheduler.getTriggerState(trigger.getKey) == TriggerState.PAUSED
+ }
 
  def triggerFired(trigger: Trigger, context: JobExecutionContext): Unit = {
  val triggerKey = s"${trigger.getKey.getGroup}.${trigger.getKey.getName}"