camunda Cannot find task with id task is null

Question

I'm beginner in Camunda. I would like to complete a task. So I start an instance by calling :

http://localhost:8080/engine-rest/process-definition/key/approve-loan/submit-form

via Postman and POST request with following data :

{
  "variables": {
    "customerId": {"value":"Niall","type":"String"},
    "amount":{"value":"100","type":"String"}
  }
}

and Content-Type : application/json

I have the following output :

{
  "links": [
    {
      "method": "GET",
      "href": "http://localhost:8080/engine-rest/process-instance/3f219a2a-138e-11e7-b49e-104a7ddf1366",
      "rel": "self"
    }
  ],
  "id": "3f219a2a-138e-11e7-b49e-104a7ddf1366",
  "definitionId": "approve-loan:2:8cd1ab3c-1303-11e7-b49e-104a7ddf1366",
  "businessKey": null,
  "caseInstanceId": null,
  "ended": false,
  "suspended": false,
  "tenantId": null
}

I looked in the camunda blog and I found I can complete the task instance by calling (POST request): http://localhost:8080/engine-rest/task/3f219a2a-138e-11e7-b49e-104a7ddf1366/complete The problem is that's not working since I have the following response :

{
  "type": "RestException",
  "message": "Cannot complete task 3f219a2a-138e-11e7-b49e-104a7ddf1366: Cannot find task with id 3f219a2a-138e-11e7-b49e-104a7ddf1366: task is null"
}

and this exception in tomcat console :

Caused by: org.camunda.bpm.engine.exception.NullValueException: Cannot find task with id 3f219a2a-138e-11e7-b49e-104a7ddf1366: task is null
        at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
        at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62)
        at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
        at java.lang.reflect.Constructor.newInstance(Constructor.java:423)
        at org.camunda.bpm.engine.impl.util.EnsureUtil.generateException(EnsureUtil.java:334)
        at org.camunda.bpm.engine.impl.util.EnsureUtil.ensureNotNull(EnsureUtil.java:49)
        at org.camunda.bpm.engine.impl.util.EnsureUtil.ensureNotNull(EnsureUtil.java:44)
        at org.camunda.bpm.engine.impl.cmd.CompleteTaskCmd.execute(CompleteTaskCmd.java:47)
        at org.camunda.bpm.engine.impl.cmd.CompleteTaskCmd.execute(CompleteTaskCmd.java:30)
        at org.camunda.bpm.engine.impl.interceptor.CommandExecutorImpl.execute(CommandExecutorImpl.java:24)
        at org.camunda.bpm.engine.impl.interceptor.CommandContextInterceptor.execute(CommandContextInterceptor.java:104)
        at org.camunda.bpm.engine.impl.interceptor.ProcessApplicationContextInterceptor.execute(ProcessApplicationContextInterceptor.java:66)
        at org.camunda.bpm.engine.impl.interceptor.LogInterceptor.execute(LogInterceptor.java:30)
        at org.camunda.bpm.engine.impl.TaskServiceImpl.complete(TaskServiceImpl.java:170)
        at org.camunda.bpm.engine.rest.sub.task.impl.TaskResourceImpl.complete(TaskResourceImpl.java:95)
        ... 37 more

I have called http://localhost:8080/engine-rest/task/?processInstanceId=3f219a2a-138e-11e7-b49e-104a7ddf1366 to get properties and the response is

[
  {
    "id": "3f220f63-138e-11e7-b49e-104a7ddf1366",
    "name": "Approve Loan",
    "assignee": "john",
    "created": "2017-03-28T10:12:12",
    "due": null,
    "followUp": null,
    "delegationState": null,
    "description": null,
    "executionId": "3f219a2a-138e-11e7-b49e-104a7ddf1366",
    "owner": null,
    "parentTaskId": null,
    "priority": 50,
    "processDefinitionId": "approve-loan:2:8cd1ab3c-1303-11e7-b49e-104a7ddf1366",
    "processInstanceId": "3f219a2a-138e-11e7-b49e-104a7ddf1366",
    "taskDefinitionKey": "UserTask_11fud4o",
    "caseExecutionId": null,
    "caseInstanceId": null,
    "caseDefinitionId": null,
    "suspended": false,
    "formKey": "embedded:app:forms/approve-loan.html",
    "tenantId": null
  }
]

I have used id and executionId but I still get the error.

Any help please ?

Answer 1

Thanks to @Zelldon : The working URL is http://localhost:8080/engine-rest/task/3f220f63-138e-11e7-b49e-104a7ddf1366/complete

I just have to take the id from the response got after the call of http://localhost:8080/engine-rest/task/?processInstanceId=3f219a2a-138e-11e7-b49e-104a7ddf1366

Please mark it as resolved since I can't.