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User tasks

A user task is used to model work that needs to be done by a human actor. When the process execution 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.

user-task

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#

User tasks support specifying a formKey attribute, using the zeebe:formDefinition extension element. The form key can be used to specify an identifier to associate a form to the user task. Tasklist supports embedded Camunda Forms, these can be embedded into the BPMN process XML as a zeebe:UserTaskForm extension element of the process element.

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 both of the following attributes can be specified simultaneously:

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

Typically, the assignee and candidate groups are defined as static values (e.g. some_username and sales, operations), but they can also be defined as expressions (e.g. = book.author and = remove(reviewers, book.author)). 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 groups.

In order 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 Cloud (login with email, Google, GitHub): email
  • Default Basic Auth (elasticsearch): username
  • IAM: username
info

Example: You log in to Tasklist using Camunda Cloud login with email using your emailadres 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.

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 representation#

A user task with a user task form and an assignment definition:

<bpmn:process id="controlProcess" name="Control Process" isExecutable="true">  <bpmn:extensionElements>    <zeebe:userTaskForm id="userTaskForm_2g7iho6">      <!-- Task Form Content -->    </zeebe:userTaskForm>  </bpmn:extensionElements>  <bpmn:userTask id="Activity_025dulo" name="Configure">    <bpmn:extensionElements>      <zeebe:assignmentDefinition assignee="= default_controller" candidateGroups="controllers, auditors" />      <zeebe:formDefinition formKey="camunda-forms:bpmn:userTaskForm_2g7iho6" />    </bpmn:extensionElements>  </bpmn:userTask></bpmn:process>

References#