cancel task when timeout

src/main/java/de/tum/cit/aet/artemis/buildagent/service/BuildJobManagementService.java

@@ -167,6 +167,7 @@ public CompletableFuture<BuildResult> executeBuildJob(BuildJobQueueItem buildJob
                 // RejectedExecutionException is thrown if the queue size limit (defined in "artemis.continuous-integration.queue-size-limit") is reached.
                 // Wrap the exception in a CompletionException so that the future is completed exceptionally and the thenAccept block is not run.
                 // This CompletionException will not resurface anywhere else as it is thrown in this completable future's separate thread.
+                future.cancel(true);
                 if (cancelledBuildJobs.contains(buildJobItem.id())) {
                     finishCancelledBuildJob(buildJobItem.repositoryInfo().assignmentRepositoryUri(), buildJobItem.id(), containerName);
                     String msg = "Build job with id " + buildJobItem.id() + " was cancelled.";
@@ -233,7 +234,7 @@ private void finishBuildJobExceptionally(String buildJobId, String containerName
         String msg = "Error while executing build job " + buildJobId + ": " + exception.getMessage();
         String stackTrace = stackTraceToString(exception);
         buildLogsMap.appendBuildLogEntry(buildJobId, new BuildLogDTO(ZonedDateTime.now(), msg + "\n" + stackTrace));
-        log.error(msg);
+        log.error(msg, exception);
 
         log.info("Getting ID of running container {}", containerName);
         String containerId = buildJobContainerService.getIDOfRunningContainer(containerName);