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Timers#

Using Modeler

    <bpmn:intermediateCatchEvent id="Event_timer">
      <bpmn:incoming>Flow_1sg7v2d</bpmn:incoming>
      <bpmn:outgoing>Flow_1nku8og</bpmn:outgoing>
      <bpmn:timerEventDefinition id="TimerEventDefinition_07xu06a">
        <bpmn:timeDuration xsi:type="bpmn:tExpression">PT2S</bpmn:timeDuration>
      </bpmn:timerEventDefinition>
    </bpmn:intermediateCatchEvent>

All Timers are persisted, therefore, if the Node.js session is restared timers will pickup where they left

Timer Types#

DateTime (not supported)#

  <timerEventDefinition>
        <timeDate>2011-03-11T12:13:14Z</timeDate>
    </timerEventDefinition>

Duration#

Example (interval lasting 10 days):

    <timerEventDefinition>
        <timeDuration>P10D</timeDuration>
    </timerEventDefinition>

Time Cycle#

Example (3 repeating intervals, each lasting 10 hours):

    <timerEventDefinition>
        <timeCycle>R3/PT10H</timeCycle>
    </timerEventDefinition>

Time Cycle accepts both ISO 8601 format and Cron format

Example for cron format:

    <timerEventDefinition>
        <bpmn:timeCycle xsi:type="bpmn:tFormalExpression">5 * * * *</bpmn:timeCycle>
    </timerEventDefinition>

Development/Test Environment Timer modification#

bpmn-server allow you to modify the timer behaviour during development without changing bpmn definition

By changing the configuration.ts to force timers to specific time

let definitionsPath = __dirname + '/processes/';
var configuration = new Configuration(
    {
        definitionsPath: definitionsPath,
        timers: {
            forceTimersDelay: 1000,
            precision: 3000,
        },

Event Types#

Event Type TimeDate Duration TimeCycle TimeCycle Repeat
Start NA NA Yes Default
Intermediate NA Yes Yes NA
Boundary Event NA Yes Yes Yes

  • Start Event support 'Time Cycle' only since duration and timeDate make no sense.

  • Intermediate Events are implemented as a normal event, will start the timer at start of the node and once the timer is completed the node will end.

  • Start Event Timers will start a new execution, therefore, they are scheduled by a cron job managed by bpmn-server.

Implementation:#

On Server start:#

  1. All start event are re-evaluated and reschedules
  2. other events that are in wait state are re-evaluated and reschedules