Manual:Extension/Workflows/Tutorial: Difference between revisions

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Such a diagram can be created with the free [https://bpmn.io/ bpmn.io] service. The [[Media:Manual:Workflows-tutorial-raw.bpmn.xml|resulting BPMN file]] needs to be modified, before it can actually be imported and used in the wiki.
Such a diagram can be created with the free [https://bpmn.io/ bpmn.io] service. The [[Media:Manual:Workflows-tutorial-raw.bpmn.xml|resulting BPMN file]] needs to be modified, before it can actually be imported and used in the wiki.


[[en:Handbuch:Erweiterung/Workflows/Tutorial]]
[de:Handbuch:Erweiterung/Workflows/Tutorial]]
[[en:{{FULLPAGENAME}}]]
[[en:{{FULLPAGENAME}}]]

Revision as of 17:04, 12 January 2023


Defining the workflow

Let's assume, we want to build a workflow, that asks for some classification of a wikipage. Based on the classification of the document, it either sends an e-mail to a member of the legal team or it first appends a wiki page and then sends the e-mail to the legal team.

The described workflow consists of four activities and one gateway. You can create a BPMN-Diagramm in the wiki to visualize the process:

Document classification workflow
Document classification workflow

Steps

To create the workflow, the following steps are necessary:

  1. Creating a custom workflow definition: MediaWiki:Classification-workflow.bpmn
  2. Creating and connecting an initiation form that adds some information about the workflow before it sends the task. MediaWiki:ContentClassificationInit.form
  3. Creating and connecting the classification form that allows the assigned user to classify the document. MediaWiki:ContentClassificiationRequest.form
  4. Adding a trigger to the wiki that defines where and how to start the workflow.

Instructions

Creating a custom workflow definition

First, let's create a page called MediaWiki:Classification-workflow.bpmn with the most basic stub XML. Each workflow that you define in the wiki needs the elements that you see here:

  • Line 1: The xml prolog
  • Line 2: The definitions element, which denotes the namespaces where the workflow elements are defined.
  • Line3: The process element, which contains all other elements.
  • Line 5: The workflow runs in the context of a specific revision of a wiki page.
  • Line 11: The workflow needs a startEvent and
  • Line 18: The workflow needs an endEvent.
<?xml version="1.0" encoding="UTF-8"?>
<bpmn:definitions xmlns:bpmn="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:wf="http://hallowelt.com/schema/bpmn/wf">
	<bpmn:process id="Classification_workflow_process">
	    <bpmn:extensionElements>
			<wf:context>
				<wf:contextItem name="pageId"/>
				<wf:contextItem name="revision"/>
			</wf:context>
		</bpmn:extensionElements>

	    <bpmn:startEvent id="TheStart">
			<bpmn:outgoing>FromTheStartToInitializeWorkflow</bpmn:outgoing>
		</bpmn:startEvent>
		<bpmn:sequenceFlow id="FromTheStartToInitializeWorkflow" sourceRef="TheStart" targetRef="InitializeWorkflow" />

        <!-- ... -->

		<bpmn:endEvent id="TheEnd">
			<bpmn:incoming>FromSendMailToTheEnd</bpmn:incoming>
		</bpmn:endEvent>

	</bpmn:process>

</bpmn:definitions>

The above stub xml only features the "Start" and "End" event including - yet to be defined - "outgoing" and "incoming" flow references.

Creating and connecting an initiation form

The initiation form allows to interact with the user who starts the workflow. It explains what happens when the workflow is started and allows to add a comment to provide some context for the user task.

We are using the MediaWiki namespace here to make sure not every user can edit the form later. But in general, such forms can be created everywhere in the wiki.

Worfklow initiation form
Worfklow initiation form

To create the initiation form:

  1. Create the page MediaWiki:ContentClassificationInit.form
  2. Paste the following form definition in source edit mode:
    {
    "lang": "json",
    "form_name": "ContentClassificationInit",
    "items": [
        {
            "name": "intro",
            "widget_label": "Click  \"Start\" to ask an expert for classification. You can leave a comment for the expert below",
            "type": "label"
        },
        {
            "name": "comment",
            "label": "Comment",
            "noLayout": true,
            "showOn": [
                "create",
                "edit",
                "view"
            ],
            "editableOn": [
                "create",
                "edit"
            ],
            "type": "textarea"
        }
    ]
}
  3. Save the page.

Next, we tell the BPMN with the following userTask to show the form: 

		<bpmn:userTask id="InitializeWorkflow" name="Start Content Classification Workflow">
			<bpmn:extensionElements>
				<wf:type>custom_form</wf:type>
				<wf:form>MediaWiki:ContentClassificationInit</wf:form>
				<wf:initializer>true</wf:initializer>
			</bpmn:extensionElements>
			<bpmn:property name="comment"></bpmn:property>
			<bpmn:incoming>FromTheStartToInitializeWorkflow</bpmn:incoming>
			<bpmn:outgoing>FromInitializeWorkflowToAskForClassification</bpmn:outgoing>
		</bpmn:userTask>
		<bpmn:sequenceFlow id="FromInitializeWorkflowToAskForClassification" sourceRef="InitializeWorkflow" targetRef="AskForClassification" />

Let's look at what this does:

  • The id and name of this activity are set to "InitializeWorkflow" and "Start Content Classification Workflow". Both values do not need to match, but usually they do.
  • <wf:type> is custom_form and tells the workflow that a form directly in the wiki (as opposed to a form located in code) is available.
  • <wf:form> points to the actual form page in the wiki
  • <wf:initializer> is set to true since it is used to show or collect some information before the actual workflow starts.

At the end, we have the incoming and outgoing flows referenced. (Note: the order of elements does not matter usually; only the nesting is important).


We add this userTask on line 16, after the line <bpmn:sequenceFlow id="FromTheStartToInitializeWorkflow" sourceRef="TheStart" targetRef="InitializeWorkflow" />:

<?xml version="1.0" encoding="UTF-8"?>
<bpmn:definitions xmlns:bpmn="http://www.omg.org/spec/BPMN/20100524/MODEL" xmlns:wf="http://hallowelt.com/schema/bpmn/wf">
	<bpmn:process id="Classification_workflow_process">
	    <bpmn:extensionElements>
			<wf:context>
				<wf:contextItem name="pageId"/>
				<wf:contextItem name="revision"/>
			</wf:context>
		</bpmn:extensionElements>

	    <bpmn:startEvent id="TheStart">
        	<bpmn:outgoing>FromTheStartToInitializ</bpmn:outgoing>
        </bpmn:startEvent>
       <bpmn:sequenceFlow id="FromTheStartToInitializeWorkflow" sourceRef="TheStart" targetRef="InitializeWorkflow" />

		<bpmn:userTask id="InitializeWorkflow" name="Start Content Classification Workflow">
			<bpmn:extensionElements>
				<wf:type>custom_form</wf:type>
				<wf:form>MediaWiki:ContentClassificationInit</wf:form>
				<wf:initializer>true</wf:initializer>
			</bpmn:extensionElements>
			<bpmn:property name="comment"></bpmn:property>
			<bpmn:incoming>FromTheStartToInitializeWorkflow</bpmn:incoming>
			<bpmn:outgoing>FromInitializeWorkflowToAskForClassification</bpmn:outgoing>
		</bpmn:userTask>
		<bpmn:sequenceFlow id="FromInitializeWorkflowToAskForClassification" sourceRef="InitializeWorkflow" targetRef="AskForClassification" />

		<bpmn:endEvent id="TheEnd">
			<bpmn:incoming>FromSendMailToTheEnd</bpmn:incoming>
		</bpmn:endEvent>

	</bpmn:process>

</bpmn:definitions>

Creating and connecting the classification form

The workflow will show a classification form to a user. This user will be defined in the workflow in a later step.

To create the classification form:

  1. Create the page MediaWiki:ContentClassificiationRequest.form
  2. Paste the following form definition in source edit mode:
{
	"lang": "json",
	"form_name": "ContentClassificationRequest",
	"items": [
		{
			"name": "intro",
			"widget_label": "Please review the given document and select an appropriate classification for the content from the list below",
			"type": "label"
		},
		{
			"name": "classification",
			"label": "Classification",
			"required": true,
			"options": [
				{
					"data": "CLSA",
					"label": "Class A"
				},
				{
					"data": "CLSB",
					"label": "Class B"
				}
			],
			"type": "dropdown",
			"widget_$overlay": true
		}
	]
}

Next, we tell the BPMN to show the form to user that receives the workflow task. For that, we add a userTask activity: 

        ...
		<bpmn:userTask id="AskForClassification" name="Provide classification">
			<bpmn:extensionElements>
				<wf:type>custom_form</wf:type>
				<wf:form>MediaWiki:ContentClassificationRequest</wf:form>
			    <wf:initializer>true</wf:initializer>
			</bpmn:extensionElements>
			<bpmn:property name="assigned_user">
				<![CDATA[{{ROOTPAGENAME:{{#show:{{FULLPAGENAME}}|?Responsible|link=none|default=TheBoss}}}}]]>
			</bpmn:property>
			<bpmn:property name="due_date">
				<![CDATA[{{#time:YmdHis|now + 7 days}}]]>
			</bpmn:property>
			<bpmn:property name="classification"></bpmn:property>
			<bpmn:incoming>FromTheStartToAskForClassification</bpmn:incoming>
			<bpmn:outgoing>FromAskForClassificationToGateway</bpmn:outgoing>
		</bpmn:userTask>
		<bpmn:sequenceFlow id="FromAskForClassificationToGateway" sourceRef="AskForClassification" targetRef="Gateway" />
		...

We should have a close look. This userTask has some additional properties besides the form reference (which was already explained in the initiation form):

  • assigned user: The assigned_user property is mandatory, as the workflow engine must know which user to query. In this case, we use some wikitext magic to calculate the assigned user from the context. The value consists of a combination of a wikitext variable and a parserfunction (this particular parserfunction is defined by the Semantic MediaWiki extension, which can be seen as a dependency here). The {{#show}} parserfunction tries to get a username from a semantic property, that may or may not be set on the page the workflow is started on. If it does not find a proper information, it will fallback to TheBoss (assuming that such a user exists on the wiki). The {{ROOTPAGENAME}} variable is just an easy way to strip the "User" namespace, if the looked up value was something like User:JaneDoe instead of just JaneDoe.
  • due date: The due_date property is also mandatory. All user facing activities need a due date. If the running activity is overdue, the workflow engine will end the workflow. In this case, we implement a concept of "lay days", as we do not have an absolute due date, but calculate it from the time the activity gets started using the {{#time}} parserfunction.
  • classification: The classification property is a random one. It must be specified, in order to allow the form to set it and the workflow context to access it. We could have provided a default value, but we want to keep it empty.

At the end, we have the incoming and outgoing flows referenced. (Note: the order of elements does not matter usually; only the nesting is important).

The gateway

Now we can proceed with adding the gateway.

The gateway will provide the two necessary paths:

  1. If the assigned user classified the document as Class A (CLSA), an email will be sent to the legal department.
  2. If the assigned user classified the document as Class B (CLSB), a wiki page will be appended with the content defined in the task "AppendWikipage"
        ...
		<bpmn:exclusiveGateway id="Gateway" name="AskForClassification.classification">
			<bpmn:incoming>FromAskForClassificationToGateway</bpmn:incoming>
			<bpmn:outgoing>FromGatewayToSendMail</bpmn:outgoing>
			<bpmn:outgoing>FromGatewayToAppendWikipage</bpmn:outgoing>
		</bpmn:exclusiveGateway>
		<bpmn:sequenceFlow id="FromGatewayToSendMail" name="CLSA" sourceRef="Gateway" targetRef="SendMail" />
		<bpmn:sequenceFlow id="FromGatewayToAppendWikipage" name="CLSB" sourceRef="Gateway" targetRef="AppendWikipage" />
		...

After setting up the gateway, we need to define the tworelated activities.

Sending an mail to the legal department

For case 1, we need the workflow to immediately send an email:

        ...
		<bpmn:task id="SendMail" name="Send mail">
			<bpmn:extensionElements>
				<wf:type>send_mail</wf:type>
			</bpmn:extensionElements>
			<bpmn:property name="recipient">
				<![CDATA[legal@company.local]]>
			</bpmn:property>
			<bpmn:property name="subject">
				<![CDATA[New "Class A" content: {{FULLPAGENAME}}]]>
			</bpmn:property>
			<bpmn:property name="body">
				<![CDATA[Please check further actions now!]]>
			</bpmn:property>
			<bpmn:incoming>FromGatewayToSendMail</bpmn:incoming>
			<bpmn:incoming>FromAppendWikipageToSendMail</bpmn:incoming>
			<bpmn:outgoing>FromEndMailToTheEnd</bpmn:outgoing>
		</bpmn:task>
		<bpmn:sequenceFlow id="FromEndMailToTheEnd" sourceRef="SendMail" targetRef="TheEnd" />
		...

Appending a wikipage

For case 2, we want the workflow to append the existing page Classification_incidents with the text shown in the content property.

This requirement can be fulfilled with the edit_page activity type:

        ...
		<bpmn:task id="AppendWikipage" name="Append wikipage">
			<bpmn:extensionElements>
				<wf:type>edit_page</wf:type>
			</bpmn:extensionElements>
			<bpmn:property name="title" default="Classification_incidents"/>
			<bpmn:property name="user" default="Mediawiki default"/>
			<bpmn:property name="content" default="* [[{{FULLPAGENAME}}]] was classified {{{AskForClassification.classification}}}"/>
			<bpmn:property name="mode" default="append"/>
			<bpmn:property name="minor" default="1"/>
			<bpmn:incoming>FromGatewayToAppendWikipage</bpmn:incoming>
			<bpmn:outgoing>FromAppendWikipageToSendMail</bpmn:outgoing>
		</bpmn:task>
		<bpmn:sequenceFlow id="FromAppendWikipageToSendMail" sourceRef="AppendWikipage" targetRef="SendMail" />
		...

The following properties are set for this activity type:

  • name: title of the wiki page to which the content will be appended.
  • user: user that is shown in the version history of the wiki page that was appended.
  • content: text that is added to the wiki page.
  • mode: shows where the text is added to the wiki page (append or ???)
  • minor: sets this page revision as a minor revision (1) or major revision (2).


 After this task is completed, the workflow will send an email to the legal department.

The final BPMN

In the end, the bpmn page for the workflow looks like this:

<?xml version="1.0" encoding="UTF-8"?>
<bpmn:definitions
	xmlns:bpmn="http://www.omg.org/spec/BPMN/20100524/MODEL"
	xmlns:wf="http://hallowelt.com/schema/bpmn/wf">

	<bpmn:process id="Classification_workflow_process">
		<bpmn:extensionElements>
			<wf:context>
				<wf:contextItem name="pageId"/>
				<wf:contextItem name="revision"/>
			</wf:context>
		</bpmn:extensionElements>
		<bpmn:startEvent id="TheStart">
			<bpmn:outgoing>FromTheStartToAskForClassification</bpmn:outgoing>
		</bpmn:startEvent>
		<bpmn:sequenceFlow id="FromTheStartToAskForClassification" sourceRef="TheStart" targetRef="AskForClassification" />

		<bpmn:userTask id="AskForClassification" name="Provide classification">
			<bpmn:extensionElements>
				<wf:type>custom_form</wf:type>
				<wf:form>MediaWiki:ContentClassificationRequest</wf:form>
				<wf:initializer>true</wf:initializer>
			</bpmn:extensionElements>
			<bpmn:property name="assigned_user">
				<![CDATA[{{ROOTPAGENAME:{{#show:{{FULLPAGENAME}}|?Responsible|link=none|default=TheBoss}}}}]]>
			</bpmn:property>
			<bpmn:property name="due_date">
				<![CDATA[{{#time:YmdHis|now + 7 days}}]]>
			</bpmn:property>
			<bpmn:property name="classification"></bpmn:property>
			<bpmn:incoming>FromTheStartToAskForClassification</bpmn:incoming>
			<bpmn:outgoing>FromAskForClassificationToGateway</bpmn:outgoing>
		</bpmn:userTask>
		<bpmn:sequenceFlow id="FromAskForClassificationToGateway" sourceRef="AskForClassification" targetRef="Gateway" />

		<bpmn:exclusiveGateway id="Gateway" name="AskForClassification.classification">
			<bpmn:incoming>FromAskForClassificationToGateway</bpmn:incoming>
			<bpmn:outgoing>FromGatewayToSendMail</bpmn:outgoing>
			<bpmn:outgoing>FromGatewayToAppendWikipage</bpmn:outgoing>
		</bpmn:exclusiveGateway>
		<bpmn:sequenceFlow id="FromGatewayToSendMail" name="CLSA" sourceRef="Gateway" targetRef="SendMail" />
		<bpmn:sequenceFlow id="FromGatewayToAppendWikipage" name="CLSB" sourceRef="Gateway" targetRef="AppendWikipage" />

		<bpmn:task id="SendMail" name="Send mail">
			<bpmn:extensionElements>
				<wf:type>send_mail</wf:type>
			</bpmn:extensionElements>
			<bpmn:property name="recipient">
				<![CDATA[legal@company.local]]>
			</bpmn:property>
			<bpmn:property name="subject">
				<![CDATA[New "Class A" content: {{FULLPAGENAME}}]]>
			</bpmn:property>
			<bpmn:property name="body">
				<![CDATA[Please check further actions now!]]>
			</bpmn:property>
			<bpmn:incoming>FromGatewayToSendMail</bpmn:incoming>
			<bpmn:incoming>FromAppendWikipageToSendMail</bpmn:incoming>
			<bpmn:outgoing>FromEndMailToTheEnd</bpmn:outgoing>
		</bpmn:task>
		<bpmn:sequenceFlow id="FromEndMailToTheEnd" sourceRef="SendMail" targetRef="TheEnd" />

		<bpmn:task id="AppendWikipage" name="Append wikipage">
			<bpmn:extensionElements>
				<wf:type>edit_page</wf:type>
			</bpmn:extensionElements>
			<bpmn:property name="title" default="Classification_incidents"/>
			<bpmn:property name="user" default="Mediawiki default"/>
			<bpmn:property name="content" default="* [[{{FULLPAGENAME}}]] was classified {{{AskForClassification.classification}}}"/>
			<bpmn:property name="mode" default="append"/>
			<bpmn:property name="minor" default="1"/>
			<bpmn:incoming>FromGatewayToAppendWikipage</bpmn:incoming>
			<bpmn:outgoing>FromAppendWikipageToSendMail</bpmn:outgoing>
		</bpmn:task>
		<bpmn:sequenceFlow id="FromAppendWikipageToSendMail" sourceRef="AppendWikipage" targetRef="SendMail" />

		<bpmn:endEvent id="TheEnd">
			<bpmn:incoming>FromSendMailToTheEnd</bpmn:incoming>
		</bpmn:endEvent>

	</bpmn:process>

</bpmn:definitions>

workflows-activity-editpage-summary

Creating a workflow trigger

For the workflow to appear in the wiki, we need to define a trigger:

  1. Click Workflow triggers in the Global actions menu.
  2. Click Add new trigger.
  3. Select the option Manual from the dropdown menu.
  4. Click Continue.
  5. Define the settings for the workflow trigger:
    • Name: Name that is displayed in the workflow selection menu.
    • Description: Explanation of the function and special features of this trigger.
    • Workflow to start: Workflow triggered by this trigger. In our case Classificiation-workflow.
    • Initial data for the workflow (optional): - Standard comment suggestion.
    • Conditions (optional): In which namespaces the workflow is displayed for selection.
  6. Click Save.


 Your workflow is now ready to be tested.

Testing the workflow

The workflow is now available in the wiki. You should test whether the following functionality is available:

  • The workflow is available to be started in the namespaces defined in the workflow trigger (if there are restrictions here).
  • The workflow is triggered.
  • The workflow is listed in the Worklfows Overview page.
  • The assigned user received a task.
  • The workflow completes correctly in case A and B.

Using bpmn.io to create workflow definitions

Such a diagram can be created with the free bpmn.io service. The resulting BPMN file needs to be modified, before it can actually be imported and used in the wiki.

[de:Handbuch:Erweiterung/Workflows/Tutorial]]



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