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  1. camunda BPM
  2. CAM-10526

Camunda External client: Exceptions when the client has nothing todo

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    • Icon: Bug Report Bug Report
    • Resolution: Unresolved
    • Icon: L3 - Default L3 - Default
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    • external task client java
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      We started with the implementation of a camunda based workflow solution. In the moment the setup is like this:

      • A spring boot application with an embedded camunda BPM (via camunda-bpm-spring-boot-starter-rest and camunda-bpm-spring-boot-starter-webapp)
      • A spring boot application with an external task client (via camunda-external-task-client)

      Everything is working fine so far. Our workflow is running and the external client is doing his job... But after a while (when there is nothing to do for the external client) is see an exception in the log of the external task client:

      15:49:09.692 [E] [TopicSubscripti] client.logError:70 - TASK/CLIENT-03001 Exception while fetch and lock task.
org.camunda.bpm.client.impl.EngineClientException: TASK/CLIENT-02002 Exception while establishing connection for request 'POST http://localhost:8080/enrichmentservice/api/rest/1.0/rest/external-task/fetchAndLock HTTP/1.1'
at org.camunda.bpm.client.impl.EngineClientLogger.exceptionWhileEstablishingConnection(EngineClientLogger.java:36)
at org.camunda.bpm.client.impl.RequestExecutor.executeRequest(RequestExecutor.java:101)
at org.camunda.bpm.client.impl.RequestExecutor.postRequest(RequestExecutor.java:74)
at org.camunda.bpm.client.impl.EngineClient.fetchAndLock(EngineClient.java:72)
at org.camunda.bpm.client.topic.impl.TopicSubscriptionManager.fetchAndLock(TopicSubscriptionManager.java:135)
at org.camunda.bpm.client.topic.impl.TopicSubscriptionManager.acquire(TopicSubscriptionManager.java:101)
at org.camunda.bpm.client.topic.impl.TopicSubscriptionManager.run(TopicSubscriptionManager.java:87)
at java.lang.Thread.run(Thread.java:748)
Caused by: org.apache.http.NoHttpResponseException: localhost:8080 failed to respond
at org.apache.http.impl.conn.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:141)
at org.apache.http.impl.conn.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:56)
at org.apache.http.impl.io.AbstractMessageParser.parse(AbstractMessageParser.java:259)
at org.apache.http.impl.DefaultBHttpClientConnection.receiveResponseHeader(DefaultBHttpClientConnection.java:163)
at org.apache.http.impl.conn.CPoolProxy.receiveResponseHeader(CPoolProxy.java:165)
at org.apache.http.protocol.HttpRequestExecutor.doReceiveResponse(HttpRequestExecutor.java:273)
at org.apache.http.protocol.HttpRequestExecutor.execute(HttpRequestExecutor.java:125)
at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:272)
at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:185)
at org.apache.http.impl.execchain.RetryExec.execute(RetryExec.java:89)
at org.apache.http.impl.execchain.RedirectExec.execute(RedirectExec.java:110)
at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:185)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:72)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:221)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:165)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:140)
at org.camunda.bpm.client.impl.RequestExecutor.executeRequest(RequestExecutor.java:88)
at org.camunda.bpm.client.impl.RequestExecutor.postRequest(RequestExecutor.java:74)
at org.camunda.bpm.client.impl.EngineClient.fetchAndLock(EngineClient.java:72)
at org.camunda.bpm.client.topic.impl.TopicSubscriptionManager.fetchAndLock(TopicSubscriptionManager.java:135)

      What could be the reason for this? Maybe Configuration error in server or client? One remark: The execution of the external task is slow (like 10-30 seconds)

      I created a complete example: See the attached Zip file with 2 eclipse projects

      To create the error scenario you have to:

      1. Start the ExampleApplication inside the spring-boot project
      2. Start the ExternalClientApp inside the Spring-Boot-Client project
      3. Wait a few minutes
        the log output of the external client should look like this:
      pojo before: ObjectValue [value=ExamplePojo [num=123, textVal=some text], isDeserialized=true, serializationDataFormat=application/x-java-serialized-object, objectTypeName=org.camunda.bpm.example.tasks.ExamplePojo, serializedValue=156 chars, isTransient=false]
pojo changed: ObjectValue [value=ExamplePojo [num=123, textVal=external changed], isDeserialized=true, serializationDataFormat=application/x-java-serialized-object, objectTypeName=org.camunda.bpm.example.tasks.ExamplePojo, serializedValue=156 chars, isTransient=false]
The External Task 28 has been completed!
The External Task 32 has been completed! (done = false)
The External Task 39 has been completed! (done = false)
The External Task 46 has been completed! (done = true)
149038 [TopicSubscriptionManager] ERROR org.camunda.bpm.client - TASK/CLIENT-03001 Exception while fetch and lock task.
org.camunda.bpm.client.impl.EngineClientException: TASK/CLIENT-02002 Exception while establishing connection for request 'POST http://localhost:8080/rest/external-task/fetchAndLock HTTP/1.1'
at org.camunda.bpm.client.impl.EngineClientLogger.exceptionWhileEstablishingConnection(EngineClientLogger.java:36)
at org.camunda.bpm.client.impl.RequestExecutor.executeRequest(RequestExecutor.java:101)
at org.camunda.bpm.client.impl.RequestExecutor.postRequest(RequestExecutor.java:74)
at org.camunda.bpm.client.impl.EngineClient.fetchAndLock(EngineClient.java:72)
at org.camunda.bpm.client.topic.impl.TopicSubscriptionManager.fetchAndLock(TopicSubscriptionManager.java:135)
at org.camunda.bpm.client.topic.impl.TopicSubscriptionManager.acquire(TopicSubscriptionManager.java:101)
at org.camunda.bpm.client.topic.impl.TopicSubscriptionManager.run(TopicSubscriptionManager.java:87)
at java.lang.Thread.run(Thread.java:748)
Caused by: org.apache.http.NoHttpResponseException: localhost:8080 failed to respond
at org.apache.http.impl.conn.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:141)
at org.apache.http.impl.conn.DefaultHttpResponseParser.parseHead(DefaultHttpResponseParser.java:56)
at org.apache.http.impl.io.AbstractMessageParser.parse(AbstractMessageParser.java:259)
at org.apache.http.impl.DefaultBHttpClientConnection.receiveResponseHeader(DefaultBHttpClientConnection.java:163)
at org.apache.http.impl.conn.CPoolProxy.receiveResponseHeader(CPoolProxy.java:157)
at org.apache.http.protocol.HttpRequestExecutor.doReceiveResponse(HttpRequestExecutor.java:273)
at org.apache.http.protocol.HttpRequestExecutor.execute(HttpRequestExecutor.java:125)
at org.apache.http.impl.execchain.MainClientExec.execute(MainClientExec.java:272)
at org.apache.http.impl.execchain.ProtocolExec.execute(ProtocolExec.java:185)
at org.apache.http.impl.execchain.RetryExec.execute(RetryExec.java:89)
at org.apache.http.impl.execchain.RedirectExec.execute(RedirectExec.java:110)
at org.apache.http.impl.client.InternalHttpClient.doExecute(InternalHttpClient.java:185)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:72)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:221)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:165)
at org.apache.http.impl.client.CloseableHttpClient.execute(CloseableHttpClient.java:140)
at org.camunda.bpm.client.impl.RequestExecutor.executeRequest(RequestExecutor.java:88)
... 6 more

        This is the controller panel for Smart Panels app

          1. camundaError.zip
            46 kB

              Unassigned Unassigned
              SirMad Mark Brockhage
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                Created:
                Updated: