User tasks

A user task is used to model work that needs to be done by a human actor. When the process instance arrives at such a user task, a new job similar to a service task is created. The process instance stops at this point and waits until the job is completed.

Applications like Tasklist can be used by humans to complete these tasks.

Alternatively, a job worker can subscribe to the job type io.camunda.zeebe:userTask to complete the job manually.

When the job is completed, the user task is completed and the process instance continues.

User task forms

A user task typically includes a form. A form contains work instructions for the user and captures the resulting information in a structured way.

However, user tasks are not limited to forms. User tasks can also be used to refer users to other applications or redirect them to a website.

You can use Camunda Forms that offer visual editing of forms directly in Camunda Modeler, or use your own forms. Forms can either be displayed in Tasklist, or handled by a custom application.

To use a form, a user task requires a form reference. Depending on your use case, three different types of form references can be used:

1. Camunda Forms (linked) provide a flexible way of linking a user task to a Camunda Form via the form ID. Forms linked this way can be deployed together with the referencing process models. To link a user task to a Camunda Form, you have to specify the ID of the Camunda Form as the formId attribute of the task's zeebe:formDefinition extension element (see the XML representation). Form ID references always refer to the latest deployed version of the Camunda Form.

   You can read more about Camunda Forms in the Camunda Forms guide or the Camunda Forms reference to explore all configuration options for form elements.

2. Camunda Forms (embedded) can be used to embed a form's JSON configuration directly into the BPMN process XML as a zeebe:UserTaskForm extension element of the process element. The embedded form can be referenced via the formKey attribute (see XML representation).

3. A custom form key can be used to specify any custom identifier to the user task. How the identifier is interpreted depends on your implementation. You can use it to associate a custom form, route to a custom application, or a URL to a web page, for example. A form referenced by a custom form key will not be shown in Tasklist.

Assignments

User tasks support specifying assignments, using the zeebe:AssignmentDefinition extension element. This can be used to define which user the task can be assigned to. One or all of the following attributes can be specified simultaneously:

• assignee: Specifies the user assigned to the task. Tasklist will claim the task for this user.
• candidateUsers: Specifies the users that the task can be assigned to.
• candidateGroups: Specifies the groups of users that the task can be assigned to.

Typically, the assignee, candidate users, and candidate groups are defined as static values (e.g. some_username, some_username, another_username and sales, operations), but they can also be defined as expressions (e.g. = book.author and = remove(reviewers, book.author) and = reviewer_roles). The expressions are evaluated on activating the user task and must result in a string for the assignee and a list of strings for the candidate users and a list of strings for the candidate groups.

For Tasklist to claim the task for a known Tasklist user, the value of the assignee must be the user's unique identifier. The unique identifier depends on the authentication method used to login to Tasklist:

• Camunda 8 (login with email, Google, GitHub): email
• Default Basic Auth (Elasticsearch): username
• IAM: username

These assignees are not related to user restrictions, which is related to the visibility of the task in Tasklist for Self-Managed. For more information, see Tasklist Authentication.

note

For example, say you log into Tasklist using Camunda 8 login with email using your email address foo@bar.com. Every time a user task activates with assignee set to value foo@bar.com, Tasklist automatically assigns it to you. You'll be able to find your new task under the task dropdown option Claimed by me.

Scheduling

User tasks support specifying a task schedule using the zeebe:taskSchedule extension element. This can be used to define when users interact with a given task. One or both of the following attributes can be specified simultaneously:

• dueDate: Specifies the due date of the user task.
• followUpDate: Specifies the follow-up date of the user task.

note

For example, you can use the followUpDate to define the latest time a user should start working on a task, and then use the dueDate to provide a deadline when the user task should be finished.

You can define the due date and follow-up date as static values (e.g. 2023-02-28T13:13:10+02:00), but you can also use expressions (e.g. = schedule.dueDate and = now() + duration("PT15S")). The expressions are evaluated on activating the user task and must result in a string conforming to an ISO 8601 combined date and time representation.

info

A specific point in time defined as ISO 8601 combined date and time representation. It must contain timezone information, either Z for UTC or a zone offset. Optionally, it can contain a zone id.

• 2019-10-01T12:00:00Z - UTC time
• 2019-10-02T08:09:40+02:00 - UTC plus two hours zone offset
• 2019-10-02T08:09:40+02:00[Europe/Berlin] - UTC plus two hours zone offset at Berlin

Variable mappings

By default, all job variables are merged into the process instance. This behavior can be customized by defining an output mapping at the user task.

Input mappings can be used to transform the variables into a format accepted by the job worker.

Task headers

A user task can define an arbitrary number of taskHeaders; they are static metadata handed to workers along with the job. The headers can be used as configuration parameters for the worker.

Additional resources

XML representations

Camunda Form (linked)

A user task with a linked Camunda Form, an assignment definition, and a task schedule:

<bpmn:userTask id="configure" name="Configure">
  <bpmn:extensionElements>
    <zeebe:formDefinition formId="configure-control-process" />
    <zeebe:assignmentDefinition assignee="= default_controller" candidateGroups="controllers, auditors" />
    <zeebe:taskSchedule dueDate="= task_finished_deadline" followUpDate="= now() + duration(&#34;P12D&#34;)" />
  </bpmn:extensionElements>
</bpmn:userTask>

Camunda Form (embedded)

A user task with an embedded Camunda Form:

<bpmn:process id="controlProcess" name="Control Process" isExecutable="true">
  <bpmn:extensionElements>
    <zeebe:userTaskForm id="userTaskForm_configure-control-process">
      <!-- Task Form Content -->
    </zeebe:userTaskForm>
  </bpmn:extensionElements>
  <bpmn:userTask id="configure" name="Configure">
    <bpmn:extensionElements>
      <zeebe:formDefinition formKey="camunda-forms:bpmn:userTaskForm_configure-control-process" />
    </bpmn:extensionElements>
  </bpmn:userTask>
</bpmn:process>

Custom form key

A user task with an external task form referenced by a custom form key:

<bpmn:userTask id="configure" name="Configure">
   <bpmn:extensionElements>
      <zeebe:formDefinition formKey="custom-key" />
   </bpmn:extensionElements>
</bpmn:userTask>

References

• Tasklist
• Form linking in Modeler
• Job handling
• Variable mappings