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Feature Request
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Resolution: Fixed
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L3 - Default
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7.15.1
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None
User Story (Required on creation):
Hello Team.
I hope you are doing well.
Following this post, handling status-based variables is important (between External task and Engine). So we have some ideas for sending new variables from the External task client to the Engine via dedicated method.
Functional Requirements (Required before implementation):
The main goal is to moderate some fields (like Progress and etc) between External tasks and Engine which is used periodically (for example we have a job like recording video that length too long. it should be done with an External Task. as it is a very long process, I need a notify progress that shows how much of the video is recorded).
As we describe the point, it will be like a specific method for sending status-based params to the Engine.
According to your contribution structure, the idea is under Community Extensions category.
Technical Requirements (Required before implementation):
We have developed the main module according to the below details.
As @jonathan.lukas (Camunda Consultant) has described, we added a new variable (like varName=progressVar) in this api :
/api/engine/engine/default/process-instance/{processInstanceId}/variables/{varName}
and we could get ProcessInstanceId by externalTask.getProcessInstanceId() method.
Following the rules, we think that it could be a specific method (it would be developed on client-side like External Task or Services) related to sending progress value to the engine. we have developed the below method for this reason.
/**
* @param processInstanceId is the id of process instance.
* @param varName is the name of variable.
* @param percent is the precent of progress.
* @return the resonse status code.
* @throws IOException
*/
public static String executRest(String processInstanceId, String varName, int percent) throws IOException {
HttpClient httpClient = HttpClientBuilder.create().build();
HttpPut request = new HttpPut(String.format("http://localhost:9999/bpms/api/engine/engine/default/process-instance/%s/variables/%s", processInstanceId, varName));
request.addHeader("content-type", "application/json");
StringEntity params = new StringEntity(String.format("{\"type\": \"string\", \"value\": \"%s\", \"valueInfo\": {}}", "% " + percent));
request.setEntity(params);
HttpResponse response = httpClient.execute(request);
return "Set variable for % " + percent + " of doing external task status code is: " + response.getStatusLine().getStatusCode();
}
Limitations of Scope (Optional):
Hints (Optional):
It's our pleasure if we can help you with developing the module.
According to the post, it could be such a necessary feature that would be helpful for users.
Let me know if it is good enough for sending a merge request (i mean "pull request") or any modification will be needed.
Thank you in advance
This is the controller panel for Smart Panels app
[CAM-13774] Sending status-based variables (like progress) from External Task to Engine periodically (via specific method)
Hi again @Tassilo Weidner
I was developing the module, then accidentally found a similar API #setVariables(Map<String, TypedValueField> variables) in ExternalTaskImpl class. It seems to cover the same functionality. am i right?
According to shouldDisplayAttributesIncludingMapsInToString tester module (below image), we could define each type of variable that we need, and then we could modify/get related value.
We need to develop exact functionality so we will appreciate if you could explain the differentiation and this method
Thank you in advance
Taha Arian
Hi tahaarian,
An ExternalTask object is passed into the handler method from where the user can set variables. However, these variables are only set when completing or handling a failure. When adding a new API method to the ExternalTaskService, it would also be possible to set variables independently of completing or handling a failure. Which is, if I understood you correctly, the functional requirement you are looking for. 
Does this make sense?
Best,
Tassilo
Hi again @Tassilo Weidner
OK Great. Thank you for your quick response.
Yes exactly, we need to set/get variables during the progression of a task.
So we keep moving forward and prepare the API.
Thank you in advance.
Best,
Taha Arian
Hi again @Tassilo Weidner
I hope your are doing well.
I have developed the API according to your advises and our requirements.
I have attached each part as below classes (new API is #setVariables(String externalTaskId, Map<String, Object> variables))
ExternalTaskService.java
/** * Set variables * * @param variables are set in the tasks ancestor execution hierarchy The key and the value represent * the variable name and its value. Map can consist of both typed and untyped variables. * * @throws NotFoundException if the task has been canceled and therefore does not exist anymore * @throws NotAcquiredException if the task's most recent lock could not be acquired * @throws NotResumedException if the corresponding process instance could not be resumed * @throws ConnectionLostException if the connection could not be established * @throws ValueMapperException * <ul> * <li> if an object cannot be serialized * <li> if no 'objectTypeName' is provided for non-null value * <li> if value is of type abstract * <li> if no suitable serializer could be found * </ul> */ public void setVariables(String externalTaskId, Map<String, Object> variables);
ExternalTaskServiceImpl.java
@Override public void setVariables(String externalTaskId,Map<String, Object> variables) { try { engineClient.setVariables(externalTaskId, variables); } catch (EngineClientException e) { throw LOG.externalTaskServiceException("setting variables for external task", e); } }
EngineClient.java
// i have defined this new path ->>> public static final String SET_VARIABLES_RESOURCE_PATH = ID_RESOURCE_PATH + "/setVariables"; public void setVariables(String taskId,Map<String, Object> variables) throws EngineClientException { Map<String, TypedValueField> typedValueDtoMap = typedValues.serializeVariables(variables); SetVariablesRequestDto payload = new SetVariablesRequestDto(workerId, typedValueDtoMap); String resourceUrl = baseUrl + SET_VARIABLES_RESOURCE_PATH; engineInteraction.postRequest(resourceUrl, payload, Void.class); }
new Class "SetVariablesRequestDto.java" was added
package org.camunda.bpm.client.task.impl.dto; import org.camunda.bpm.client.impl.RequestDto; import org.camunda.bpm.client.variable.impl.TypedValueField; import java.util.Map; /** * @author Taha Arian */ public class SetVariablesRequestDto extends RequestDto { protected Map<String, TypedValueField> variables; public SetVariablesRequestDto(String workerId, Map<String, TypedValueField> variables) { super(workerId); this.variables = variables; } public Map<String, TypedValueField> getVariables() { return variables; } }
in the end, i have wrote a tester class as below
ChargeCardWorkerTest.java
package org.camunda.bpm.client.task; import org.camunda.bpm.client.ExternalTaskClient; import java.util.HashMap; import java.util.Map; import java.util.logging.Logger; public class ChargeCardWorkerTest { private final static Logger LOGGER = Logger.getLogger(ChargeCardWorkerTest.class.getName()); public static void main(String[] args) { ExternalTaskClient client = ExternalTaskClient.create() .baseUrl("http://localhost:8080/engine-rest") .asyncResponseTimeout(10000) // long polling timeout .build(); client.subscribe("charge-card") .lockDuration(1000) .handler((externalTask, externalTaskService) -> { Map<String, Object> vars = new HashMap<String, Object>(); vars.put("ProgressTest",10); externalTaskService.setVariables(externalTask.getId(),vars); externalTask.getVariable("ProgressTest"); externalTaskService.complete(externalTask); }) .open(); } }
I will appreciate if you could check it out and let me know your feedback (maybe i did some wrong things 
).
We will make a pull request if you are ok with this method.
Thank you in advance
Best regards,
Taha Arian
Hi tahaarian,
Thank you for sharing your code. It looks good in general.
However, could you please raise a pull request already? It is much easier for me to review and provide feedback on GitHub.
Regarding your code:
- Let's not introduce a completely new REST API endpoint /external-task/{externalTaskId}/setVariables. Instead, let's use the already existing endpoint POST /process-instance/{process-instance-id}/variables to create new variables. The process instance id can be retrieved from the passed External Task.
- Also, let's add these methods to set variables by process instance id and by ExternalTask object:
@Override public void setVariables(String processInstanceId, Map<String, Object> variables) { try { engineClient.setVariables(processInstanceId, Map<String, Object> variables); } catch (EngineClientException e) { // ... } } @Override public void setVariable(ExternalTask externalTask, Map<String, Object> variables) { String processInstanceId = externalTask.getProcessInstanceId(); try { engineClient.setVariables(processInstanceId, Map<String, Object> variables); } catch (EngineClientException e) { // ... } }
Best,
Tassilo
Hi again @Tassilo Weidner
Thank you for your feedback. Ok great, I will send a pull request.
Sorry for late reply, actually we need to check the new API on our project and its ok now
I have modified these items that you said. I am so thankful for your help and support
Best,
Taha Arian
Hi tahaarian,
Thanks! I'm so happy about your contribution efforts 
When you create a pull request, please clearly link back to this issue, assign me (my GitHub username is @tasso94 and maybe ping me here.
Otherwise, your pull request might end up with another team member.
Best,
Tassilo
Hi @Tassilo Weidner
Your welcome my friend
It was created as below link. but I can't assign it to you,maybe i don't have enough access
https://github.com/camunda/camunda-bpm-platform/pull/1603
I will appreciate if you could check it out and let me know your feedback.
Best Regards,
Taha Arian
Hi tahaarian,
I have assigned the pull request to me and I can have a look into it this Friday.
Best,
Tassilo
Hi @Tassilo Weidner
You are welcome
Great
Yes, I will prepare the module and raise a pull request according to your hint
Thank you in advance
Taha Arian