rhauch commented on a change in pull request #10822: URL: https://github.com/apache/kafka/pull/10822#discussion_r655658286
########## File path: connect/runtime/src/main/java/org/apache/kafka/connect/runtime/distributed/DistributedHerder.java ########## @@ -1063,6 +1076,112 @@ public int generation() { return generation; } + @Override + public void restartConnectorAndTasks( + RestartRequest request, + Callback<ConnectorStateInfo> callback + ) { + final String connectorName = request.connectorName(); + addRequest( + () -> { + if (checkRebalanceNeeded(callback)) { + return null; + } + if (!configState.connectors().contains(request.connectorName())) { + callback.onCompletion(new NotFoundException("Unknown connector: " + connectorName), null); + return null; + } + if (isLeader()) { + // Write a restart request to the config backing store, to be executed asynchronously in tick() + configBackingStore.putRestartRequest(request); + // Compute and send the response that this was accepted + Optional<RestartPlan> maybePlan = buildRestartPlanFor(request); + if (!maybePlan.isPresent()) { + callback.onCompletion(new NotFoundException("Status for connector " + connectorName + " not found", null), null); + } else { + RestartPlan plan = maybePlan.get(); + callback.onCompletion(null, plan.restartConnectorStateInfo()); + } + } else { + callback.onCompletion(new NotLeaderException("Only the leader can process restart requests.", leaderUrl()), null); + } + + return null; + }, + forwardErrorCallback(callback) + ); + } + + /** + * Process all pending restart requests. There can be at most one request per connector. + * + * <p>This method is called from within the {@link #tick()} method. + */ + void processRestartRequests() { + List<RestartRequest> restartRequests; + synchronized (this) { + if (pendingRestartRequests.isEmpty()) { + return; + } + //dequeue into a local list to minimize the work being done within the synchronized block + restartRequests = new ArrayList<>(pendingRestartRequests.values()); + pendingRestartRequests.clear(); + } + for (RestartRequest restartRequest : restartRequests) { + try { + doRestartConnectorAndTasks(restartRequest); + } catch (Exception e) { + log.warn("Unexpected error while trying to process " + restartRequest + ", the restart request will be skipped.", e); + } + } + } + + protected synchronized void doRestartConnectorAndTasks(RestartRequest request) { + final String connectorName = request.connectorName(); + Optional<RestartPlan> maybePlan = buildRestartPlanFor(request); + if (!maybePlan.isPresent()) { + log.debug("Skipping restart of connector '{}' since no status is available: {}", connectorName, request); + return; + } + RestartPlan plan = maybePlan.get(); + log.info("Executing {}", plan); + + // If requested, stop the connector and any tasks, marking each as restarting + final ExtendedAssignment currentAssignments = assignment; + final Collection<ConnectorTaskId> assignedIdsToRestart = plan.taskIdsToRestart() + .stream() + .filter(taskId -> currentAssignments.tasks().contains(taskId)) + .collect(Collectors.toList()); + final boolean restartConnector = plan.restartConnector() && currentAssignments.connectors().contains(connectorName); + final boolean restartTasks = !assignedIdsToRestart.isEmpty(); + if (restartConnector) { + worker.stopAndAwaitConnector(connectorName); + recordRestarting(connectorName); + } + if (restartTasks) { + // Stop the tasks and mark as restarting + worker.stopAndAwaitTasks(assignedIdsToRestart); + assignedIdsToRestart.forEach(this::recordRestarting); + } + + // Now restart the connector and tasks + if (restartConnector) { + startConnector(connectorName, (error, targetState) -> { + if (error == null) { + log.info("Connector '{}' successfully restarted", connectorName); + } else { + log.error("Failed to restart connector '" + connectorName + "'", error); + } + }); + } + if (restartTasks) { + log.debug("Restarting {} of {} tasks for {}", plan.restartTaskCount(), plan.totalTaskCount(), request); + plan.taskIdsToRestart().forEach(this::startTask); + log.debug("Restarted {} of {} tasks for {} as requested", plan.restartTaskCount(), plan.totalTaskCount(), request); + } Review comment: > Adding retry logic to this PR can make the PR complex, I would vote for adding it in a separate PR. I would agree. We're not sure whether we need this behavior yet, so I'm +1 for keeping it simple in this PR and adding it in the future only if we discover a need for it. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org