org.apache.kafka.connect.runtime.distributed.DistributedHerder Maven / Gradle / Ivy
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* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache License, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.apache.kafka.connect.runtime.distributed;
import org.apache.kafka.clients.CommonClientConfigs;
import org.apache.kafka.common.config.ConfigDef;
import org.apache.kafka.common.config.ConfigValue;
import org.apache.kafka.common.errors.WakeupException;
import org.apache.kafka.common.metrics.Sensor;
import org.apache.kafka.common.metrics.stats.Avg;
import org.apache.kafka.common.metrics.stats.CumulativeSum;
import org.apache.kafka.common.metrics.stats.Max;
import org.apache.kafka.common.utils.Exit;
import org.apache.kafka.common.utils.LogContext;
import org.apache.kafka.common.utils.ThreadUtils;
import org.apache.kafka.common.utils.Time;
import org.apache.kafka.common.utils.Utils;
import org.apache.kafka.connect.connector.Connector;
import org.apache.kafka.connect.connector.policy.ConnectorClientConfigOverridePolicy;
import org.apache.kafka.connect.errors.AlreadyExistsException;
import org.apache.kafka.connect.errors.ConnectException;
import org.apache.kafka.connect.errors.NotFoundException;
import org.apache.kafka.connect.runtime.AbstractHerder;
import org.apache.kafka.connect.runtime.CloseableConnectorContext;
import org.apache.kafka.connect.runtime.ConnectMetrics;
import org.apache.kafka.connect.runtime.ConnectMetrics.MetricGroup;
import org.apache.kafka.connect.runtime.ConnectMetricsRegistry;
import org.apache.kafka.connect.runtime.ConnectorConfig;
import org.apache.kafka.connect.runtime.HerderConnectorContext;
import org.apache.kafka.connect.runtime.HerderRequest;
import org.apache.kafka.connect.runtime.RestartPlan;
import org.apache.kafka.connect.runtime.RestartRequest;
import org.apache.kafka.connect.runtime.SessionKey;
import org.apache.kafka.connect.runtime.SinkConnectorConfig;
import org.apache.kafka.connect.runtime.SourceConnectorConfig;
import org.apache.kafka.connect.runtime.TargetState;
import org.apache.kafka.connect.runtime.TaskStatus;
import org.apache.kafka.connect.runtime.Worker;
import org.apache.kafka.connect.runtime.rest.InternalRequestSignature;
import org.apache.kafka.connect.runtime.rest.RestClient;
import org.apache.kafka.connect.runtime.rest.RestServer;
import org.apache.kafka.connect.runtime.rest.entities.ConnectorInfo;
import org.apache.kafka.connect.runtime.rest.entities.ConnectorStateInfo;
import org.apache.kafka.connect.runtime.rest.entities.TaskInfo;
import org.apache.kafka.connect.runtime.rest.errors.BadRequestException;
import org.apache.kafka.connect.runtime.rest.errors.ConnectRestException;
import org.apache.kafka.connect.sink.SinkConnector;
import org.apache.kafka.connect.storage.ConfigBackingStore;
import org.apache.kafka.connect.storage.StatusBackingStore;
import org.apache.kafka.connect.util.Callback;
import org.apache.kafka.connect.util.ConnectorTaskId;
import org.apache.kafka.connect.util.SinkUtils;
import org.slf4j.Logger;
import javax.crypto.KeyGenerator;
import javax.crypto.SecretKey;
import javax.ws.rs.core.Response;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.NavigableSet;
import java.util.NoSuchElementException;
import java.util.Objects;
import java.util.Optional;
import java.util.Set;
import java.util.concurrent.Callable;
import java.util.concurrent.ConcurrentSkipListSet;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.LinkedBlockingDeque;
import java.util.concurrent.ThreadPoolExecutor;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.atomic.AtomicBoolean;
import java.util.concurrent.atomic.AtomicInteger;
import java.util.concurrent.atomic.AtomicLong;
import java.util.concurrent.atomic.AtomicReference;
import java.util.stream.Collectors;
import static org.apache.kafka.connect.runtime.WorkerConfig.TOPIC_TRACKING_ENABLE_CONFIG;
import static org.apache.kafka.connect.runtime.distributed.ConnectProtocol.CONNECT_PROTOCOL_V0;
import static org.apache.kafka.connect.runtime.distributed.ConnectProtocolCompatibility.EAGER;
import static org.apache.kafka.connect.runtime.distributed.IncrementalCooperativeConnectProtocol.CONNECT_PROTOCOL_V1;
import static org.apache.kafka.connect.runtime.distributed.IncrementalCooperativeConnectProtocol.CONNECT_PROTOCOL_V2;
/**
*
* Distributed "herder" that coordinates with other workers to spread work across multiple processes.
*
*
* Under the hood, this is implemented as a group managed by Kafka's group membership facilities (i.e. the generalized
* group/consumer coordinator). Each instance of DistributedHerder joins the group and indicates what it's current
* configuration state is (where it is in the configuration log). The group coordinator selects one member to take
* this information and assign each instance a subset of the active connectors & tasks to execute. This assignment
* is currently performed in a simple round-robin fashion, but this is not guaranteed -- the herder may also choose
* to, e.g., use a sticky assignment to avoid the usual start/stop costs associated with connectors and tasks. Once
* an assignment is received, the DistributedHerder simply runs its assigned connectors and tasks in a Worker.
*
*
* In addition to distributing work, the DistributedHerder uses the leader determined during the work assignment
* to select a leader for this generation of the group who is responsible for other tasks that can only be performed
* by a single node at a time. Most importantly, this includes writing updated configurations for connectors and tasks,
* (and therefore, also for creating, destroy, and scaling up/down connectors).
*
*
* The DistributedHerder uses a single thread for most of its processing. This includes processing
* config changes, handling task rebalances and serving requests from the HTTP layer. The latter are pushed
* into a queue until the thread has time to handle them. A consequence of this is that requests can get blocked
* behind a worker rebalance. When the herder knows that a rebalance is expected, it typically returns an error
* immediately to the request, but this is not always possible (in particular when another worker has requested
* the rebalance). Similar to handling HTTP requests, config changes which are observed asynchronously by polling
* the config log are batched for handling in the work thread.
*
*/
public class DistributedHerder extends AbstractHerder implements Runnable {
private static final AtomicInteger CONNECT_CLIENT_ID_SEQUENCE = new AtomicInteger(1);
private final Logger log;
private static final long FORWARD_REQUEST_SHUTDOWN_TIMEOUT_MS = TimeUnit.SECONDS.toMillis(10);
private static final long START_AND_STOP_SHUTDOWN_TIMEOUT_MS = TimeUnit.SECONDS.toMillis(1);
private static final long RECONFIGURE_CONNECTOR_TASKS_BACKOFF_MS = 250;
private static final int START_STOP_THREAD_POOL_SIZE = 8;
private static final short BACKOFF_RETRIES = 5;
private final AtomicLong requestSeqNum = new AtomicLong();
private final Time time;
private final HerderMetrics herderMetrics;
private final List uponShutdown;
private final String workerGroupId;
private final int workerSyncTimeoutMs;
private final long workerTasksShutdownTimeoutMs;
private final int workerUnsyncBackoffMs;
private final int keyRotationIntervalMs;
private final String requestSignatureAlgorithm;
private final List keySignatureVerificationAlgorithms;
private final KeyGenerator keyGenerator;
private final ExecutorService herderExecutor;
private final ExecutorService forwardRequestExecutor;
private final ExecutorService startAndStopExecutor;
private final WorkerGroupMember member;
private final AtomicBoolean stopping;
private final boolean isTopicTrackingEnabled;
// Track enough information about the current membership state to be able to determine which requests via the API
// and the from other nodes are safe to process
private boolean rebalanceResolved;
private ExtendedAssignment runningAssignment = ExtendedAssignment.empty();
private Set tasksToRestart = new HashSet<>();
// visible for testing
ExtendedAssignment assignment;
private boolean canReadConfigs;
// visible for testing
protected ClusterConfigState configState;
// To handle most external requests, like creating or destroying a connector, we can use a generic request where
// the caller specifies all the code that should be executed.
final NavigableSet requests = new ConcurrentSkipListSet<>();
// Config updates can be collected and applied together when possible. Also, we need to take care to rebalance when
// needed (e.g. task reconfiguration, which requires everyone to coordinate offset commits).
private Set connectorConfigUpdates = new HashSet<>();
private Set taskConfigUpdates = new HashSet<>();
// Similarly collect target state changes (when observed by the config storage listener) for handling in the
// herder's main thread.
private Set connectorTargetStateChanges = new HashSet<>();
private boolean needsReconfigRebalance;
private volatile int generation;
private volatile long scheduledRebalance;
private volatile SecretKey sessionKey;
private volatile long keyExpiration;
private short currentProtocolVersion;
private short backoffRetries;
// visible for testing
// The latest pending restart request for each named connector
final Map pendingRestartRequests = new HashMap<>();
private final DistributedConfig config;
/**
* Create a herder that will form a Connect cluster with other {@link DistributedHerder} instances (in this or other JVMs)
* that have the same group ID.
*
* @param config the configuration for the worker; may not be null
* @param time the clock to use; may not be null
* @param worker the {@link Worker} instance to use; may not be null
* @param kafkaClusterId the identifier of the Kafka cluster to use for internal topics; may not be null
* @param statusBackingStore the backing store for statuses; may not be null
* @param configBackingStore the backing store for connector configurations; may not be null
* @param restUrl the URL of this herder's REST API; may not be null
* @param connectorClientConfigOverridePolicy the policy specifying the client configuration properties that may be overridden
* in connector configurations; may not be null
* @param uponShutdown any {@link AutoCloseable} objects that should be closed when this herder is {@link #stop() stopped},
* after all services and resources owned by this herder are stopped
*/
public DistributedHerder(DistributedConfig config,
Time time,
Worker worker,
String kafkaClusterId,
StatusBackingStore statusBackingStore,
ConfigBackingStore configBackingStore,
String restUrl,
ConnectorClientConfigOverridePolicy connectorClientConfigOverridePolicy,
AutoCloseable... uponShutdown) {
this(config, worker, worker.workerId(), kafkaClusterId, statusBackingStore, configBackingStore, null, restUrl, worker.metrics(),
time, connectorClientConfigOverridePolicy, uponShutdown);
configBackingStore.setUpdateListener(new ConfigUpdateListener());
}
// visible for testing
DistributedHerder(DistributedConfig config,
Worker worker,
String workerId,
String kafkaClusterId,
StatusBackingStore statusBackingStore,
ConfigBackingStore configBackingStore,
WorkerGroupMember member,
String restUrl,
ConnectMetrics metrics,
Time time,
ConnectorClientConfigOverridePolicy connectorClientConfigOverridePolicy,
AutoCloseable... uponShutdown) {
super(worker, workerId, kafkaClusterId, statusBackingStore, configBackingStore, connectorClientConfigOverridePolicy);
this.time = time;
this.herderMetrics = new HerderMetrics(metrics);
this.workerGroupId = config.getString(DistributedConfig.GROUP_ID_CONFIG);
this.workerSyncTimeoutMs = config.getInt(DistributedConfig.WORKER_SYNC_TIMEOUT_MS_CONFIG);
this.workerTasksShutdownTimeoutMs = config.getLong(DistributedConfig.TASK_SHUTDOWN_GRACEFUL_TIMEOUT_MS_CONFIG);
this.workerUnsyncBackoffMs = config.getInt(DistributedConfig.WORKER_UNSYNC_BACKOFF_MS_CONFIG);
this.requestSignatureAlgorithm = config.getString(DistributedConfig.INTER_WORKER_SIGNATURE_ALGORITHM_CONFIG);
this.keyRotationIntervalMs = config.getInt(DistributedConfig.INTER_WORKER_KEY_TTL_MS_CONFIG);
this.keySignatureVerificationAlgorithms = config.getList(DistributedConfig.INTER_WORKER_VERIFICATION_ALGORITHMS_CONFIG);
this.keyGenerator = config.getInternalRequestKeyGenerator();
this.isTopicTrackingEnabled = config.getBoolean(TOPIC_TRACKING_ENABLE_CONFIG);
this.uponShutdown = Arrays.asList(uponShutdown);
String clientIdConfig = config.getString(CommonClientConfigs.CLIENT_ID_CONFIG);
String clientId = clientIdConfig.length() <= 0 ? "connect-" + CONNECT_CLIENT_ID_SEQUENCE.getAndIncrement() : clientIdConfig;
LogContext logContext = new LogContext("[Worker clientId=" + clientId + ", groupId=" + this.workerGroupId + "] ");
log = logContext.logger(DistributedHerder.class);
this.member = member != null
? member
: new WorkerGroupMember(config, restUrl, this.configBackingStore,
new RebalanceListener(time), time, clientId, logContext);
this.herderExecutor = new ThreadPoolExecutor(1, 1, 0L,
TimeUnit.MILLISECONDS,
new LinkedBlockingDeque<>(1),
ThreadUtils.createThreadFactory(
this.getClass().getSimpleName() + "-" + clientId + "-%d", false));
this.forwardRequestExecutor = Executors.newFixedThreadPool(1,
ThreadUtils.createThreadFactory(
"ForwardRequestExecutor-" + clientId + "-%d", false));
this.startAndStopExecutor = Executors.newFixedThreadPool(START_STOP_THREAD_POOL_SIZE,
ThreadUtils.createThreadFactory(
"StartAndStopExecutor-" + clientId + "-%d", false));
this.config = config;
stopping = new AtomicBoolean(false);
configState = ClusterConfigState.EMPTY;
rebalanceResolved = true; // If we still need to follow up after a rebalance occurred, starting up tasks
needsReconfigRebalance = false;
canReadConfigs = true; // We didn't try yet, but Configs are readable until proven otherwise
scheduledRebalance = Long.MAX_VALUE;
keyExpiration = Long.MAX_VALUE;
sessionKey = null;
backoffRetries = BACKOFF_RETRIES;
currentProtocolVersion = ConnectProtocolCompatibility.compatibility(
config.getString(DistributedConfig.CONNECT_PROTOCOL_CONFIG)
).protocolVersion();
if (!internalRequestValidationEnabled(currentProtocolVersion)) {
log.warn(
"Internal request verification will be disabled for this cluster as this worker's {} configuration has been set to '{}'. "
+ "If this is not intentional, either remove the '{}' configuration from the worker config file or change its value "
+ "to '{}'. If this configuration is left as-is, the cluster will be insecure; for more information, see KIP-507: "
+ "https://cwiki.apache.org/confluence/display/KAFKA/KIP-507%3A+Securing+Internal+Connect+REST+Endpoints",
DistributedConfig.CONNECT_PROTOCOL_CONFIG,
config.getString(DistributedConfig.CONNECT_PROTOCOL_CONFIG),
DistributedConfig.CONNECT_PROTOCOL_CONFIG,
ConnectProtocolCompatibility.SESSIONED.name()
);
}
}
@Override
public void start() {
this.herderExecutor.submit(this);
}
@Override
public void run() {
try {
log.info("Herder starting");
startServices();
log.info("Herder started");
running = true;
while (!stopping.get()) {
tick();
}
halt();
log.info("Herder stopped");
herderMetrics.close();
} catch (Throwable t) {
log.error("Uncaught exception in herder work thread, exiting: ", t);
Exit.exit(1);
} finally {
running = false;
}
}
// public for testing
public void tick() {
// The main loop does two primary things: 1) drive the group membership protocol, responding to rebalance events
// as they occur, and 2) handle external requests targeted at the leader. All the "real" work of the herder is
// performed in this thread, which keeps synchronization straightforward at the cost of some operations possibly
// blocking up this thread (especially those in callbacks due to rebalance events).
try {
// if we failed to read to end of log before, we need to make sure the issue was resolved before joining group
// Joining and immediately leaving for failure to read configs is exceedingly impolite
if (!canReadConfigs) {
if (readConfigToEnd(workerSyncTimeoutMs)) {
canReadConfigs = true;
} else {
return; // Safe to return and tick immediately because readConfigToEnd will do the backoff for us
}
}
log.debug("Ensuring group membership is still active");
member.ensureActive();
// Ensure we're in a good state in our group. If not restart and everything should be setup to rejoin
if (!handleRebalanceCompleted()) return;
} catch (WakeupException e) {
// May be due to a request from another thread, or might be stopping. If the latter, we need to check the
// flag immediately. If the former, we need to re-run the ensureActive call since we can't handle requests
// unless we're in the group.
log.trace("Woken up while ensure group membership is still active");
return;
}
long now = time.milliseconds();
if (checkForKeyRotation(now)) {
log.debug("Distributing new session key");
keyExpiration = Long.MAX_VALUE;
try {
configBackingStore.putSessionKey(new SessionKey(
keyGenerator.generateKey(),
now
));
} catch (Exception e) {
log.info("Failed to write new session key to config topic; forcing a read to the end of the config topic before possibly retrying");
canReadConfigs = false;
return;
}
}
// Process any external requests
// TODO: Some of these can be performed concurrently or even optimized away entirely.
// For example, if three different connectors are slated to be restarted, it's fine to
// restart all three at the same time instead.
// Another example: if multiple configurations are submitted for the same connector,
// the only one that actually has to be written to the config topic is the
// most-recently one.
long nextRequestTimeoutMs = Long.MAX_VALUE;
while (true) {
final DistributedHerderRequest next = peekWithoutException();
if (next == null) {
break;
} else if (now >= next.at) {
requests.pollFirst();
} else {
nextRequestTimeoutMs = next.at - now;
break;
}
try {
next.action().call();
next.callback().onCompletion(null, null);
} catch (Throwable t) {
next.callback().onCompletion(t, null);
}
}
// Process all pending connector restart requests
processRestartRequests();
if (scheduledRebalance < Long.MAX_VALUE) {
nextRequestTimeoutMs = Math.min(nextRequestTimeoutMs, Math.max(scheduledRebalance - now, 0));
rebalanceResolved = false;
log.debug("Scheduled rebalance at: {} (now: {} nextRequestTimeoutMs: {}) ",
scheduledRebalance, now, nextRequestTimeoutMs);
}
if (isLeader() && internalRequestValidationEnabled() && keyExpiration < Long.MAX_VALUE) {
nextRequestTimeoutMs = Math.min(nextRequestTimeoutMs, Math.max(keyExpiration - now, 0));
log.debug("Scheduled next key rotation at: {} (now: {} nextRequestTimeoutMs: {}) ",
keyExpiration, now, nextRequestTimeoutMs);
}
// Process any configuration updates
AtomicReference> connectorConfigUpdatesCopy = new AtomicReference<>();
AtomicReference> connectorTargetStateChangesCopy = new AtomicReference<>();
AtomicReference> taskConfigUpdatesCopy = new AtomicReference<>();
boolean shouldReturn;
if (member.currentProtocolVersion() == CONNECT_PROTOCOL_V0) {
shouldReturn = updateConfigsWithEager(connectorConfigUpdatesCopy,
connectorTargetStateChangesCopy);
// With eager protocol we should return immediately if needsReconfigRebalance has
// been set to retain the old workflow
if (shouldReturn) {
return;
}
if (connectorConfigUpdatesCopy.get() != null) {
processConnectorConfigUpdates(connectorConfigUpdatesCopy.get());
}
if (connectorTargetStateChangesCopy.get() != null) {
processTargetStateChanges(connectorTargetStateChangesCopy.get());
}
} else {
shouldReturn = updateConfigsWithIncrementalCooperative(connectorConfigUpdatesCopy,
connectorTargetStateChangesCopy, taskConfigUpdatesCopy);
if (connectorConfigUpdatesCopy.get() != null) {
processConnectorConfigUpdates(connectorConfigUpdatesCopy.get());
}
if (connectorTargetStateChangesCopy.get() != null) {
processTargetStateChanges(connectorTargetStateChangesCopy.get());
}
if (taskConfigUpdatesCopy.get() != null) {
processTaskConfigUpdatesWithIncrementalCooperative(taskConfigUpdatesCopy.get());
}
if (shouldReturn) {
return;
}
}
// Let the group take any actions it needs to
try {
log.trace("Polling for group activity; will wait for {}ms or until poll is interrupted by "
+ "either config backing store updates or a new external request",
nextRequestTimeoutMs);
member.poll(nextRequestTimeoutMs);
// Ensure we're in a good state in our group. If not restart and everything should be setup to rejoin
handleRebalanceCompleted();
} catch (WakeupException e) { // FIXME should not be WakeupException
log.trace("Woken up while polling for group activity");
// Ignore. Just indicates we need to check the exit flag, for requested actions, etc.
}
}
private boolean checkForKeyRotation(long now) {
SecretKey key;
long expiration;
synchronized (this) {
key = sessionKey;
expiration = keyExpiration;
}
if (internalRequestValidationEnabled()) {
if (isLeader()) {
if (key == null) {
log.debug("Internal request signing is enabled but no session key has been distributed yet. "
+ "Distributing new key now.");
return true;
} else if (expiration <= now) {
log.debug("Existing key has expired. Distributing new key now.");
return true;
} else if (!key.getAlgorithm().equals(keyGenerator.getAlgorithm())
|| key.getEncoded().length != keyGenerator.generateKey().getEncoded().length) {
log.debug("Previously-distributed key uses different algorithm/key size "
+ "than required by current worker configuration. Distributing new key now.");
return true;
}
} else if (key == null && configState.sessionKey() != null) {
// This happens on startup for follower workers; the snapshot contains the session key,
// but no callback in the config update listener has been fired for it yet.
sessionKey = configState.sessionKey().key();
}
}
return false;
}
private synchronized boolean updateConfigsWithEager(AtomicReference> connectorConfigUpdatesCopy,
AtomicReference> connectorTargetStateChangesCopy) {
// This branch is here to avoid creating a snapshot if not needed
if (needsReconfigRebalance
|| !connectorConfigUpdates.isEmpty()
|| !connectorTargetStateChanges.isEmpty()) {
log.trace("Handling config updates with eager rebalancing");
// Connector reconfigs only need local updates since there is no coordination between workers required.
// However, if connectors were added or removed, work needs to be rebalanced since we have more work
// items to distribute among workers.
configState = configBackingStore.snapshot();
if (needsReconfigRebalance) {
// Task reconfigs require a rebalance. Request the rebalance, clean out state, and then restart
// this loop, which will then ensure the rebalance occurs without any other requests being
// processed until it completes.
log.debug("Requesting rebalance due to reconfiguration of tasks (needsReconfigRebalance: {})",
needsReconfigRebalance);
member.requestRejoin();
needsReconfigRebalance = false;
// Any connector config updates or target state changes will be addressed during the rebalance too
connectorConfigUpdates.clear();
connectorTargetStateChanges.clear();
return true;
} else {
if (!connectorConfigUpdates.isEmpty()) {
// We can't start/stop while locked since starting connectors can cause task updates that will
// require writing configs, which in turn make callbacks into this class from another thread that
// require acquiring a lock. This leads to deadlock. Instead, just copy the info we need and process
// the updates after unlocking.
connectorConfigUpdatesCopy.set(connectorConfigUpdates);
connectorConfigUpdates = new HashSet<>();
}
if (!connectorTargetStateChanges.isEmpty()) {
// Similarly for target state changes which can cause connectors to be restarted
connectorTargetStateChangesCopy.set(connectorTargetStateChanges);
connectorTargetStateChanges = new HashSet<>();
}
}
} else {
log.trace("Skipping config updates with eager rebalancing "
+ "since no config rebalance is required "
+ "and there are no connector config, task config, or target state changes pending");
}
return false;
}
private synchronized boolean updateConfigsWithIncrementalCooperative(AtomicReference> connectorConfigUpdatesCopy,
AtomicReference> connectorTargetStateChangesCopy,
AtomicReference> taskConfigUpdatesCopy) {
boolean retValue = false;
// This branch is here to avoid creating a snapshot if not needed
if (needsReconfigRebalance
|| !connectorConfigUpdates.isEmpty()
|| !connectorTargetStateChanges.isEmpty()
|| !taskConfigUpdates.isEmpty()) {
log.trace("Handling config updates with incremental cooperative rebalancing");
// Connector reconfigs only need local updates since there is no coordination between workers required.
// However, if connectors were added or removed, work needs to be rebalanced since we have more work
// items to distribute among workers.
configState = configBackingStore.snapshot();
if (needsReconfigRebalance) {
log.debug("Requesting rebalance due to reconfiguration of tasks (needsReconfigRebalance: {})",
needsReconfigRebalance);
member.requestRejoin();
needsReconfigRebalance = false;
retValue = true;
}
if (!connectorConfigUpdates.isEmpty()) {
// We can't start/stop while locked since starting connectors can cause task updates that will
// require writing configs, which in turn make callbacks into this class from another thread that
// require acquiring a lock. This leads to deadlock. Instead, just copy the info we need and process
// the updates after unlocking.
connectorConfigUpdatesCopy.set(connectorConfigUpdates);
connectorConfigUpdates = new HashSet<>();
}
if (!connectorTargetStateChanges.isEmpty()) {
// Similarly for target state changes which can cause connectors to be restarted
connectorTargetStateChangesCopy.set(connectorTargetStateChanges);
connectorTargetStateChanges = new HashSet<>();
}
if (!taskConfigUpdates.isEmpty()) {
// Similarly for task config updates
taskConfigUpdatesCopy.set(taskConfigUpdates);
taskConfigUpdates = new HashSet<>();
}
} else {
log.trace("Skipping config updates with incremental cooperative rebalancing "
+ "since no config rebalance is required "
+ "and there are no connector config, task config, or target state changes pending");
}
return retValue;
}
private void processConnectorConfigUpdates(Set connectorConfigUpdates) {
// If we only have connector config updates, we can just bounce the updated connectors that are
// currently assigned to this worker.
Set localConnectors = assignment == null ? Collections.emptySet() : new HashSet<>(assignment.connectors());
log.trace("Processing connector config updates; "
+ "currently-owned connectors are {}, and to-be-updated connectors are {}",
localConnectors,
connectorConfigUpdates);
for (String connectorName : connectorConfigUpdates) {
if (!localConnectors.contains(connectorName)) {
log.trace("Skipping config update for connector {} as it is not owned by this worker",
connectorName);
continue;
}
boolean remains = configState.contains(connectorName);
log.info("Handling connector-only config update by {} connector {}",
remains ? "restarting" : "stopping", connectorName);
worker.stopAndAwaitConnector(connectorName);
// The update may be a deletion, so verify we actually need to restart the connector
if (remains) {
startConnector(connectorName, (error, result) -> {
if (error != null) {
log.error("Failed to start connector '" + connectorName + "'", error);
}
});
}
}
}
private void processTargetStateChanges(Set connectorTargetStateChanges) {
log.trace("Processing target state updates; "
+ "currently-known connectors are {}, and to-be-updated connectors are {}",
configState.connectors(), connectorTargetStateChanges);
for (String connector : connectorTargetStateChanges) {
TargetState targetState = configState.targetState(connector);
if (!configState.connectors().contains(connector)) {
log.debug("Received target state change for unknown connector: {}", connector);
continue;
}
// we must propagate the state change to the worker so that the connector's
// tasks can transition to the new target state
worker.setTargetState(connector, targetState, (error, newState) -> {
if (error != null) {
log.error("Failed to transition connector to target state", error);
return;
}
// additionally, if the worker is running the connector itself, then we need to
// request reconfiguration to ensure that config changes while paused take effect
if (newState == TargetState.STARTED) {
requestTaskReconfiguration(connector);
}
});
}
}
private void processTaskConfigUpdatesWithIncrementalCooperative(Set taskConfigUpdates) {
Set localTasks = assignment == null
? Collections.emptySet()
: new HashSet<>(assignment.tasks());
log.trace("Processing task config updates with incremental cooperative rebalance protocol; "
+ "currently-owned tasks are {}, and to-be-updated tasks are {}",
localTasks, taskConfigUpdates);
Set connectorsWhoseTasksToStop = taskConfigUpdates.stream()
.map(ConnectorTaskId::connector).collect(Collectors.toSet());
List tasksToStop = localTasks.stream()
.filter(taskId -> connectorsWhoseTasksToStop.contains(taskId.connector()))
.collect(Collectors.toList());
log.info("Handling task config update by restarting tasks {}", tasksToStop);
worker.stopAndAwaitTasks(tasksToStop);
tasksToRestart.addAll(tasksToStop);
}
// public for testing
public void halt() {
synchronized (this) {
// Clean up any connectors and tasks that are still running.
log.info("Stopping connectors and tasks that are still assigned to this worker.");
List> callables = new ArrayList<>();
for (String connectorName : new ArrayList<>(worker.connectorNames())) {
callables.add(getConnectorStoppingCallable(connectorName));
}
for (ConnectorTaskId taskId : new ArrayList<>(worker.taskIds())) {
callables.add(getTaskStoppingCallable(taskId));
}
startAndStop(callables);
member.stop();
// Explicitly fail any outstanding requests so they actually get a response and get an
// understandable reason for their failure.
DistributedHerderRequest request = requests.pollFirst();
while (request != null) {
request.callback().onCompletion(new ConnectException("Worker is shutting down"), null);
request = requests.pollFirst();
}
stopServices();
}
}
@Override
protected void stopServices() {
try {
super.stopServices();
} finally {
this.uponShutdown.forEach(closeable -> Utils.closeQuietly(closeable, closeable != null ? closeable.toString() : ""));
}
}
@Override
public void stop() {
log.info("Herder stopping");
stopping.set(true);
member.wakeup();
herderExecutor.shutdown();
try {
if (!herderExecutor.awaitTermination(workerTasksShutdownTimeoutMs, TimeUnit.MILLISECONDS))
herderExecutor.shutdownNow();
forwardRequestExecutor.shutdown();
startAndStopExecutor.shutdown();
if (!forwardRequestExecutor.awaitTermination(FORWARD_REQUEST_SHUTDOWN_TIMEOUT_MS, TimeUnit.MILLISECONDS))
forwardRequestExecutor.shutdownNow();
if (!startAndStopExecutor.awaitTermination(START_AND_STOP_SHUTDOWN_TIMEOUT_MS, TimeUnit.MILLISECONDS))
startAndStopExecutor.shutdownNow();
} catch (InterruptedException e) {
// ignore
}
log.info("Herder stopped");
running = false;
}
@Override
public void connectors(final Callback> callback) {
log.trace("Submitting connector listing request");
addRequest(
() -> {
if (!checkRebalanceNeeded(callback))
callback.onCompletion(null, configState.connectors());
return null;
},
forwardErrorCallback(callback)
);
}
@Override
public void connectorInfo(final String connName, final Callback callback) {
log.trace("Submitting connector info request {}", connName);
addRequest(
() -> {
if (checkRebalanceNeeded(callback))
return null;
if (!configState.contains(connName)) {
callback.onCompletion(
new NotFoundException("Connector " + connName + " not found"), null);
} else {
callback.onCompletion(null, connectorInfo(connName));
}
return null;
},
forwardErrorCallback(callback)
);
}
@Override
public void tasksConfig(String connName, final Callback>> callback) {
log.trace("Submitting tasks config request {}", connName);
addRequest(
() -> {
if (checkRebalanceNeeded(callback))
return null;
if (!configState.contains(connName)) {
callback.onCompletion(new NotFoundException("Connector " + connName + " not found"), null);
} else {
callback.onCompletion(null, buildTasksConfig(connName));
}
return null;
},
forwardErrorCallback(callback)
);
}
@Override
protected Map rawConfig(String connName) {
return configState.rawConnectorConfig(connName);
}
@Override
public void connectorConfig(String connName, final Callback> callback) {
log.trace("Submitting connector config read request {}", connName);
super.connectorConfig(connName, callback);
}
@Override
public void deleteConnectorConfig(final String connName, final Callback> callback) {
addRequest(
() -> {
log.trace("Handling connector config request {}", connName);
if (!isLeader()) {
callback.onCompletion(new NotLeaderException("Only the leader can delete connector configs.", leaderUrl()), null);
return null;
}
if (!configState.contains(connName)) {
callback.onCompletion(new NotFoundException("Connector " + connName + " not found"), null);
} else {
log.trace("Removing connector config {} {}", connName, configState.connectors());
configBackingStore.removeConnectorConfig(connName);
callback.onCompletion(null, new Created<>(false, null));
}
return null;
},
forwardErrorCallback(callback)
);
}
@Override
protected Map validateBasicConnectorConfig(Connector connector,
ConfigDef configDef,
Map config) {
Map validatedConfig = super.validateBasicConnectorConfig(connector, configDef, config);
if (connector instanceof SinkConnector) {
ConfigValue validatedName = validatedConfig.get(ConnectorConfig.NAME_CONFIG);
String name = (String) validatedName.value();
if (workerGroupId.equals(SinkUtils.consumerGroupId(name))) {
validatedName.addErrorMessage("Consumer group for sink connector named " + name +
" conflicts with Connect worker group " + workerGroupId);
}
}
return validatedConfig;
}
@Override
public void putConnectorConfig(final String connName, final Map config, final boolean allowReplace,
final Callback> callback) {
log.trace("Submitting connector config write request {}", connName);
addRequest(
() -> {
validateConnectorConfig(config, (error, configInfos) -> {
if (error != null) {
callback.onCompletion(error, null);
return;
}
// Complete the connector config write via another herder request in order to
// perform the write to the backing store (or forward to the leader) during
// the "external request" portion of the tick loop
addRequest(
() -> {
if (maybeAddConfigErrors(configInfos, callback)) {
return null;
}
log.trace("Handling connector config request {}", connName);
if (!isLeader()) {
callback.onCompletion(new NotLeaderException("Only the leader can set connector configs.", leaderUrl()), null);
return null;
}
boolean exists = configState.contains(connName);
if (!allowReplace && exists) {
callback.onCompletion(new AlreadyExistsException("Connector " + connName + " already exists"), null);
return null;
}
log.trace("Submitting connector config {} {} {}", connName, allowReplace, configState.connectors());
configBackingStore.putConnectorConfig(connName, config);
// Note that we use the updated connector config despite the fact that we don't have an updated
// snapshot yet. The existing task info should still be accurate.
ConnectorInfo info = new ConnectorInfo(connName, config, configState.tasks(connName),
// validateConnectorConfig have checked the existence of CONNECTOR_CLASS_CONFIG
connectorTypeForClass(config.get(ConnectorConfig.CONNECTOR_CLASS_CONFIG)));
callback.onCompletion(null, new Created<>(!exists, info));
return null;
},
forwardErrorCallback(callback)
);
});
return null;
},
forwardErrorCallback(callback)
);
}
@Override
public void requestTaskReconfiguration(final String connName) {
log.trace("Submitting connector task reconfiguration request {}", connName);
addRequest(
() -> {
reconfigureConnectorTasksWithRetry(time.milliseconds(), connName);
return null;
},
(error, result) -> {
if (error != null) {
log.error("Unexpected error during task reconfiguration: ", error);
log.error("Task reconfiguration for {} failed unexpectedly, this connector will not be properly reconfigured unless manually triggered.", connName);
}
}
);
}
@Override
public void taskConfigs(final String connName, final Callback> callback) {
log.trace("Submitting get task configuration request {}", connName);
addRequest(
() -> {
if (checkRebalanceNeeded(callback))
return null;
if (!configState.contains(connName)) {
callback.onCompletion(new NotFoundException("Connector " + connName + " not found"), null);
} else {
List result = new ArrayList<>();
for (int i = 0; i < configState.taskCount(connName); i++) {
ConnectorTaskId id = new ConnectorTaskId(connName, i);
result.add(new TaskInfo(id, configState.rawTaskConfig(id)));
}
callback.onCompletion(null, result);
}
return null;
},
forwardErrorCallback(callback)
);
}
@Override
public void putTaskConfigs(final String connName, final List> configs, final Callback callback, InternalRequestSignature requestSignature) {
log.trace("Submitting put task configuration request {}", connName);
if (internalRequestValidationEnabled()) {
ConnectRestException requestValidationError = null;
if (requestSignature == null) {
requestValidationError = new BadRequestException("Internal request missing required signature");
} else if (!keySignatureVerificationAlgorithms.contains(requestSignature.keyAlgorithm())) {
requestValidationError = new BadRequestException(String.format(
"This worker does not support the '%s' key signing algorithm used by other workers. "
+ "This worker is currently configured to use: %s. "
+ "Check that all workers' configuration files permit the same set of signature algorithms, "
+ "and correct any misconfigured worker and restart it.",
requestSignature.keyAlgorithm(),
keySignatureVerificationAlgorithms
));
} else {
if (!requestSignature.isValid(sessionKey)) {
requestValidationError = new ConnectRestException(
Response.Status.FORBIDDEN,
"Internal request contained invalid signature."
);
}
}
if (requestValidationError != null) {
callback.onCompletion(requestValidationError, null);
return;
}
}
addRequest(
() -> {
if (!isLeader())
callback.onCompletion(new NotLeaderException("Only the leader may write task configurations.", leaderUrl()), null);
else if (!configState.contains(connName))
callback.onCompletion(new NotFoundException("Connector " + connName + " not found"), null);
else {
configBackingStore.putTaskConfigs(connName, configs);
callback.onCompletion(null, null);
}
return null;
},
forwardErrorCallback(callback)
);
}
@Override
public void restartConnector(final String connName, final Callback callback) {
restartConnector(0, connName, callback);
}
@Override
public HerderRequest restartConnector(final long delayMs, final String connName, final Callback callback) {
return addRequest(
delayMs,
() -> {
if (checkRebalanceNeeded(callback))
return null;
if (!configState.connectors().contains(connName)) {
callback.onCompletion(new NotFoundException("Unknown connector: " + connName), null);
return null;
}
if (assignment.connectors().contains(connName)) {
try {
worker.stopAndAwaitConnector(connName);
startConnector(connName, callback);
} catch (Throwable t) {
callback.onCompletion(t, null);
}
} else if (isLeader()) {
callback.onCompletion(new NotAssignedException("Cannot restart connector since it is not assigned to this member", member.ownerUrl(connName)), null);
} else {
callback.onCompletion(new NotLeaderException("Only the leader can process restart requests.", leaderUrl()), null);
}
return null;
},
forwardErrorCallback(callback));
}
@Override
public void restartTask(final ConnectorTaskId id, final Callback callback) {
addRequest(
() -> {
if (checkRebalanceNeeded(callback))
return null;
if (!configState.connectors().contains(id.connector())) {
callback.onCompletion(new NotFoundException("Unknown connector: " + id.connector()), null);
return null;
}
if (configState.taskConfig(id) == null) {
callback.onCompletion(new NotFoundException("Unknown task: " + id), null);
return null;
}
if (assignment.tasks().contains(id)) {
try {
worker.stopAndAwaitTask(id);
if (startTask(id))
callback.onCompletion(null, null);
else
callback.onCompletion(new ConnectException("Failed to start task: " + id), null);
} catch (Throwable t) {
callback.onCompletion(t, null);
}
} else if (isLeader()) {
callback.onCompletion(new NotAssignedException("Cannot restart task since it is not assigned to this member", member.ownerUrl(id)), null);
} else {
callback.onCompletion(new NotLeaderException("Cannot restart task since it is not assigned to this member", leaderUrl()), null);
}
return null;
},
forwardErrorCallback(callback));
}
@Override
public int generation() {
return generation;
}
@Override
public void restartConnectorAndTasks(RestartRequest request, Callback 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 plan = buildRestartPlan(request);
if (!plan.isPresent()) {
callback.onCompletion(new NotFoundException("Status for connector " + connectorName + " not found", null), null);
} else {
callback.onCompletion(null, plan.get().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.
*
* This method is called from within the {@link #tick()} method.
*/
void processRestartRequests() {
List 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();
}
restartRequests.forEach(restartRequest -> {
try {
doRestartConnectorAndTasks(restartRequest);
} catch (Exception e) {
log.warn("Unexpected error while trying to process " + restartRequest + ", the restart request will be skipped.", e);
}
});
}
/**
* Builds and executes a restart plan for the connector and its tasks from request.
* Execution of a plan involves triggering the stop of eligible connector/tasks and then queuing the start for eligible connector/tasks.
*
* @param request the request to restart connector and tasks
*/
protected synchronized void doRestartConnectorAndTasks(RestartRequest request) {
String connectorName = request.connectorName();
Optional maybePlan = buildRestartPlan(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 assignedIdsToRestart = plan.taskIdsToRestart()
.stream()
.filter(taskId -> currentAssignments.tasks().contains(taskId))
.collect(Collectors.toList());
final boolean restartConnector = plan.shouldRestartConnector() && currentAssignments.connectors().contains(connectorName);
final boolean restartTasks = !assignedIdsToRestart.isEmpty();
if (restartConnector) {
worker.stopAndAwaitConnector(connectorName);
onRestart(connectorName);
}
if (restartTasks) {
// Stop the tasks and mark as restarting
worker.stopAndAwaitTasks(assignedIdsToRestart);
assignedIdsToRestart.forEach(this::onRestart);
}
// Now restart the connector and tasks
if (restartConnector) {
try {
startConnector(connectorName, (error, targetState) -> {
if (error == null) {
log.info("Connector '{}' restart successful", connectorName);
} else {
log.error("Connector '{}' restart failed", connectorName, error);
}
});
} catch (Throwable t) {
log.error("Connector '{}' restart failed", connectorName, t);
}
}
if (restartTasks) {
log.debug("Restarting {} of {} tasks for {}", plan.restartTaskCount(), plan.totalTaskCount(), request);
plan.taskIdsToRestart().forEach(taskId -> {
try {
if (startTask(taskId)) {
log.info("Task '{}' restart successful", taskId);
} else {
log.error("Task '{}' restart failed", taskId);
}
} catch (Throwable t) {
log.error("Task '{}' restart failed", taskId, t);
}
});
log.debug("Restarted {} of {} tasks for {} as requested", plan.restartTaskCount(), plan.totalTaskCount(), request);
}
log.info("Completed {}", plan);
}
// Should only be called from work thread, so synchronization should not be needed
private boolean isLeader() {
return assignment != null && member.memberId().equals(assignment.leader());
}
/**
* Get the URL for the leader's REST interface, or null if we do not have the leader's URL yet.
*/
private String leaderUrl() {
if (assignment == null)
return null;
return assignment.leaderUrl();
}
/**
* Handle post-assignment operations, either trying to resolve issues that kept assignment from completing, getting
* this node into sync and its work started.
*
* @return false if we couldn't finish
*/
private boolean handleRebalanceCompleted() {
if (rebalanceResolved) {
log.trace("Returning early because rebalance is marked as resolved (rebalanceResolved: true)");
return true;
}
log.debug("Handling completed but unresolved rebalance");
// We need to handle a variety of cases after a rebalance:
// 1. Assignment failed
// 1a. We are the leader for the round. We will be leader again if we rejoin now, so we need to catch up before
// even attempting to. If we can't we should drop out of the group because we will block everyone from making
// progress. We can backoff and try rejoining later.
// 1b. We are not the leader. We might need to catch up. If we're already caught up we can rejoin immediately,
// otherwise, we just want to wait reasonable amount of time to catch up and rejoin if we are ready.
// 2. Assignment succeeded.
// 2a. We are caught up on configs. Awesome! We can proceed to run our assigned work.
// 2b. We need to try to catch up - try reading configs for reasonable amount of time.
boolean needsReadToEnd = false;
boolean needsRejoin = false;
if (assignment.failed()) {
needsRejoin = true;
if (isLeader()) {
log.warn("Join group completed, but assignment failed and we are the leader. Reading to end of config and retrying.");
needsReadToEnd = true;
} else if (configState.offset() < assignment.offset()) {
log.warn("Join group completed, but assignment failed and we lagging. Reading to end of config and retrying.");
needsReadToEnd = true;
} else {
log.warn("Join group completed, but assignment failed. We were up to date, so just retrying.");
}
} else {
if (configState.offset() < assignment.offset()) {
log.warn("Catching up to assignment's config offset.");
needsReadToEnd = true;
}
}
long now = time.milliseconds();
if (scheduledRebalance <= now) {
log.debug("Requesting rebalance because scheduled rebalance timeout has been reached "
+ "(now: {} scheduledRebalance: {}", scheduledRebalance, now);
needsRejoin = true;
scheduledRebalance = Long.MAX_VALUE;
}
if (needsReadToEnd) {
// Force exiting this method to avoid creating any connectors/tasks and require immediate rejoining if
// we timed out. This should only happen if we failed to read configuration for long enough,
// in which case giving back control to the main loop will prevent hanging around indefinitely after getting kicked out of the group.
// We also indicate to the main loop that we failed to readConfigs so it will check that the issue was resolved before trying to join the group
if (readConfigToEnd(workerSyncTimeoutMs)) {
canReadConfigs = true;
} else {
canReadConfigs = false;
needsRejoin = true;
}
}
if (needsRejoin) {
member.requestRejoin();
return false;
}
// Should still validate that they match since we may have gone *past* the required offset, in which case we
// should *not* start any tasks and rejoin
if (configState.offset() != assignment.offset()) {
log.info("Current config state offset {} does not match group assignment {}. Forcing rebalance.", configState.offset(), assignment.offset());
member.requestRejoin();
return false;
}
startWork();
// We only mark this as resolved once we've actually started work, which allows us to correctly track whether
// what work is currently active and running. If we bail early, the main tick loop + having requested rejoin
// guarantees we'll attempt to rejoin before executing this method again.
herderMetrics.rebalanceSucceeded(time.milliseconds());
rebalanceResolved = true;
if (!assignment.revokedConnectors().isEmpty() || !assignment.revokedTasks().isEmpty()) {
assignment.revokedConnectors().clear();
assignment.revokedTasks().clear();
member.requestRejoin();
return false;
}
return true;
}
/**
* Try to read to the end of the config log within the given timeout
* @param timeoutMs maximum time to wait to sync to the end of the log
* @return true if successful, false if timed out
*/
private boolean readConfigToEnd(long timeoutMs) {
if (configState.offset() < assignment.offset()) {
log.info("Current config state offset {} is behind group assignment {}, reading to end of config log", configState.offset(), assignment.offset());
} else {
log.info("Reading to end of config log; current config state offset: {}", configState.offset());
}
try {
configBackingStore.refresh(timeoutMs, TimeUnit.MILLISECONDS);
configState = configBackingStore.snapshot();
log.info("Finished reading to end of log and updated config snapshot, new config log offset: {}", configState.offset());
backoffRetries = BACKOFF_RETRIES;
return true;
} catch (TimeoutException e) {
// in case reading the log takes too long, leave the group to ensure a quick rebalance (although by default we should be out of the group already)
// and back off to avoid a tight loop of rejoin-attempt-to-catch-up-leave
log.warn("Didn't reach end of config log quickly enough", e);
member.maybeLeaveGroup("taking too long to read the log");
backoff(workerUnsyncBackoffMs);
return false;
}
}
private void backoff(long ms) {
if (ConnectProtocolCompatibility.fromProtocolVersion(currentProtocolVersion) == EAGER) {
time.sleep(ms);
return;
}
if (backoffRetries > 0) {
int rebalanceDelayFraction =
config.getInt(DistributedConfig.SCHEDULED_REBALANCE_MAX_DELAY_MS_CONFIG) / 10 / backoffRetries;
time.sleep(rebalanceDelayFraction);
--backoffRetries;
return;
}
ExtendedAssignment runningAssignmentSnapshot;
synchronized (this) {
runningAssignmentSnapshot = ExtendedAssignment.duplicate(runningAssignment);
}
log.info("Revoking current running assignment {} because after {} retries the worker "
+ "has not caught up with the latest Connect cluster updates",
runningAssignmentSnapshot, BACKOFF_RETRIES);
member.revokeAssignment(runningAssignmentSnapshot);
backoffRetries = BACKOFF_RETRIES;
}
private void startAndStop(Collection> callables) {
try {
startAndStopExecutor.invokeAll(callables);
} catch (InterruptedException e) {
// ignore
}
}
private void startWork() {
// Start assigned connectors and tasks
List> callables = new ArrayList<>();
// The sets in runningAssignment may change when onRevoked is called voluntarily by this
// herder (e.g. when a broker coordinator failure is detected). Otherwise the
// runningAssignment is always replaced by the assignment here.
synchronized (this) {
log.info("Starting connectors and tasks using config offset {}", assignment.offset());
log.debug("Received assignment: {}", assignment);
log.debug("Currently running assignment: {}", runningAssignment);
for (String connectorName : assignmentDifference(assignment.connectors(), runningAssignment.connectors())) {
callables.add(getConnectorStartingCallable(connectorName));
}
// These tasks have been stopped by this worker due to task reconfiguration. In order to
// restart them, they are removed just before the overall task startup from the set of
// currently running tasks. Therefore, they'll be restarted only if they are included in
// the assignment that was just received after rebalancing.
log.debug("Tasks to restart from currently running assignment: {}", tasksToRestart);
runningAssignment.tasks().removeAll(tasksToRestart);
tasksToRestart.clear();
for (ConnectorTaskId taskId : assignmentDifference(assignment.tasks(), runningAssignment.tasks())) {
callables.add(getTaskStartingCallable(taskId));
}
}
startAndStop(callables);
synchronized (this) {
runningAssignment = member.currentProtocolVersion() == CONNECT_PROTOCOL_V0
? ExtendedAssignment.empty()
: assignment;
}
log.info("Finished starting connectors and tasks");
}
// arguments should assignment collections (connectors or tasks) and should not be null
private static Collection assignmentDifference(Collection update, Collection running) {
if (running.isEmpty()) {
return update;
}
HashSet diff = new HashSet<>(update);
diff.removeAll(running);
return diff;
}
private boolean startTask(ConnectorTaskId taskId) {
log.info("Starting task {}", taskId);
return worker.startTask(
taskId,
configState,
configState.connectorConfig(taskId.connector()),
configState.taskConfig(taskId),
this,
configState.targetState(taskId.connector())
);
}
private Callable getTaskStartingCallable(final ConnectorTaskId taskId) {
return () -> {
try {
startTask(taskId);
} catch (Throwable t) {
log.error("Couldn't instantiate task {} because it has an invalid task configuration. This task will not execute until reconfigured.",
taskId, t);
onFailure(taskId, t);
}
return null;
};
}
private Callable getTaskStoppingCallable(final ConnectorTaskId taskId) {
return () -> {
worker.stopAndAwaitTask(taskId);
return null;
};
}
// Helper for starting a connector with the given name, which will extract & parse the config, generate connector
// context and add to the worker. This needs to be called from within the main worker thread for this herder.
// The callback is invoked after the connector has finished startup and generated task configs, or failed in the process.
private void startConnector(String connectorName, Callback callback) {
log.info("Starting connector {}", connectorName);
final Map configProps = configState.connectorConfig(connectorName);
final CloseableConnectorContext ctx = new HerderConnectorContext(this, connectorName);
final TargetState initialState = configState.targetState(connectorName);
final Callback onInitialStateChange = (error, newState) -> {
if (error != null) {
callback.onCompletion(new ConnectException("Failed to start connector: " + connectorName, error), null);
return;
}
// Use newState here in case the connector has been paused right after being created
if (newState == TargetState.STARTED) {
addRequest(
() -> {
// Request configuration since this could be a brand new connector. However, also only update those
// task configs if they are actually different from the existing ones to avoid unnecessary updates when this is
// just restoring an existing connector.
reconfigureConnectorTasksWithRetry(time.milliseconds(), connectorName);
callback.onCompletion(null, null);
return null;
},
forwardErrorCallback(callback)
);
} else {
callback.onCompletion(null, null);
}
};
worker.startConnector(connectorName, configProps, ctx, this, initialState, onInitialStateChange);
}
private Callable getConnectorStartingCallable(final String connectorName) {
return () -> {
try {
startConnector(connectorName, (error, result) -> {
if (error != null) {
log.error("Failed to start connector '" + connectorName + "'", error);
}
});
} catch (Throwable t) {
log.error("Unexpected error while trying to start connector " + connectorName, t);
onFailure(connectorName, t);
}
return null;
};
}
private Callable getConnectorStoppingCallable(final String connectorName) {
return () -> {
try {
worker.stopAndAwaitConnector(connectorName);
} catch (Throwable t) {
log.error("Failed to shut down connector " + connectorName, t);
}
return null;
};
}
private void reconfigureConnectorTasksWithRetry(long initialRequestTime, final String connName) {
reconfigureConnector(connName, (error, result) -> {
// If we encountered an error, we don't have much choice but to just retry. If we don't, we could get
// stuck with a connector that thinks it has generated tasks, but wasn't actually successful and therefore
// never makes progress. The retry has to run through a DistributedHerderRequest since this callback could be happening
// from the HTTP request forwarding thread.
if (error != null) {
if (isPossibleExpiredKeyException(initialRequestTime, error)) {
log.debug("Failed to reconfigure connector's tasks ({}), possibly due to expired session key. Retrying after backoff", connName);
} else {
log.error("Failed to reconfigure connector's tasks ({}), retrying after backoff:", connName, error);
}
addRequest(RECONFIGURE_CONNECTOR_TASKS_BACKOFF_MS,
() -> {
reconfigureConnectorTasksWithRetry(initialRequestTime, connName);
return null;
}, (err, res) -> {
if (err != null) {
log.error("Unexpected error during connector task reconfiguration: ", err);
log.error("Task reconfiguration for {} failed unexpectedly, this connector will not be properly reconfigured unless manually triggered.", connName);
}
}
);
}
});
}
boolean isPossibleExpiredKeyException(long initialRequestTime, Throwable error) {
if (error instanceof ConnectRestException) {
ConnectRestException connectError = (ConnectRestException) error;
return connectError.statusCode() == Response.Status.FORBIDDEN.getStatusCode()
&& initialRequestTime + TimeUnit.MINUTES.toMillis(1) >= time.milliseconds();
}
return false;
}
// Updates configurations for a connector by requesting them from the connector, filling in parameters provided
// by the system, then checks whether any configs have actually changed before submitting the new configs to storage
private void reconfigureConnector(final String connName, final Callback cb) {
try {
if (!worker.isRunning(connName)) {
log.info("Skipping reconfiguration of connector {} since it is not running", connName);
return;
}
Map configs = configState.connectorConfig(connName);
ConnectorConfig connConfig;
if (worker.isSinkConnector(connName)) {
connConfig = new SinkConnectorConfig(plugins(), configs);
} else {
connConfig = new SourceConnectorConfig(plugins(), configs, worker.isTopicCreationEnabled());
}
final List> taskProps = worker.connectorTaskConfigs(connName, connConfig);
boolean changed = false;
int currentNumTasks = configState.taskCount(connName);
if (taskProps.size() != currentNumTasks) {
log.debug("Change in connector task count from {} to {}, writing updated task configurations", currentNumTasks, taskProps.size());
changed = true;
} else {
int index = 0;
for (Map taskConfig : taskProps) {
if (!taskConfig.equals(configState.taskConfig(new ConnectorTaskId(connName, index)))) {
log.debug("Change in task configurations, writing updated task configurations");
changed = true;
break;
}
index++;
}
}
if (changed) {
List> rawTaskProps = reverseTransform(connName, configState, taskProps);
if (isLeader()) {
configBackingStore.putTaskConfigs(connName, rawTaskProps);
cb.onCompletion(null, null);
} else {
// We cannot forward the request on the same thread because this reconfiguration can happen as a result of connector
// addition or removal. If we blocked waiting for the response from leader, we may be kicked out of the worker group.
forwardRequestExecutor.submit(() -> {
try {
String leaderUrl = leaderUrl();
if (Utils.isBlank(leaderUrl)) {
cb.onCompletion(new ConnectException("Request to leader to " +
"reconfigure connector tasks failed " +
"because the URL of the leader's REST interface is empty!"), null);
return;
}
String reconfigUrl = RestServer.urlJoin(leaderUrl, "/connectors/" + connName + "/tasks");
log.trace("Forwarding task configurations for connector {} to leader", connName);
RestClient.httpRequest(reconfigUrl, "POST", null, rawTaskProps, null, config, sessionKey, requestSignatureAlgorithm);
cb.onCompletion(null, null);
} catch (ConnectException e) {
log.error("Request to leader to reconfigure connector tasks failed", e);
cb.onCompletion(e, null);
}
});
}
}
} catch (Throwable t) {
cb.onCompletion(t, null);
}
}
private boolean checkRebalanceNeeded(Callback callback) {
// Raise an error if we are expecting a rebalance to begin. This prevents us from forwarding requests
// based on stale leadership or assignment information
if (needsReconfigRebalance) {
callback.onCompletion(new RebalanceNeededException("Request cannot be completed because a rebalance is expected"), null);
return true;
}
return false;
}
DistributedHerderRequest addRequest(Callable action, Callback callback) {
return addRequest(0, action, callback);
}
DistributedHerderRequest addRequest(long delayMs, Callable action, Callback callback) {
DistributedHerderRequest req = new DistributedHerderRequest(time.milliseconds() + delayMs, requestSeqNum.incrementAndGet(), action, callback);
requests.add(req);
if (peekWithoutException() == req)
member.wakeup();
return req;
}
private boolean internalRequestValidationEnabled() {
return internalRequestValidationEnabled(member.currentProtocolVersion());
}
private static boolean internalRequestValidationEnabled(short protocolVersion) {
return protocolVersion >= CONNECT_PROTOCOL_V2;
}
private DistributedHerderRequest peekWithoutException() {
try {
return requests.isEmpty() ? null : requests.first();
} catch (NoSuchElementException e) {
// Ignore exception. Should be rare. Means that the collection became empty between
// checking the size and retrieving the first element.
}
return null;
}
public class ConfigUpdateListener implements ConfigBackingStore.UpdateListener {
@Override
public void onConnectorConfigRemove(String connector) {
log.info("Connector {} config removed", connector);
synchronized (DistributedHerder.this) {
// rebalance after connector removal to ensure that existing tasks are balanced among workers
if (configState.contains(connector))
needsReconfigRebalance = true;
connectorConfigUpdates.add(connector);
}
member.wakeup();
}
@Override
public void onConnectorConfigUpdate(String connector) {
log.info("Connector {} config updated", connector);
// Stage the update and wake up the work thread. Connector config *changes* only need the one connector
// to be bounced. However, this callback may also indicate a connector *addition*, which does require
// a rebalance, so we need to be careful about what operation we request.
synchronized (DistributedHerder.this) {
if (!configState.contains(connector))
needsReconfigRebalance = true;
connectorConfigUpdates.add(connector);
}
member.wakeup();
}
@Override
public void onTaskConfigUpdate(Collection tasks) {
log.info("Tasks {} configs updated", tasks);
// Stage the update and wake up the work thread.
// The set of tasks is recorder for incremental cooperative rebalancing, in which
// tasks don't get restarted unless they are balanced between workers.
// With eager rebalancing there's no need to record the set of tasks because task reconfigs
// always need a rebalance to ensure offsets get committed. In eager rebalancing the
// recorded set of tasks remains unused.
// TODO: As an optimization, some task config updates could avoid a rebalance. In particular, single-task
// connectors clearly don't need any coordination.
synchronized (DistributedHerder.this) {
needsReconfigRebalance = true;
taskConfigUpdates.addAll(tasks);
}
member.wakeup();
}
@Override
public void onConnectorTargetStateChange(String connector) {
log.info("Connector {} target state change", connector);
synchronized (DistributedHerder.this) {
connectorTargetStateChanges.add(connector);
}
member.wakeup();
}
@Override
public void onSessionKeyUpdate(SessionKey sessionKey) {
log.info("Session key updated");
synchronized (DistributedHerder.this) {
DistributedHerder.this.sessionKey = sessionKey.key();
// Track the expiration of the key.
// Followers will receive rotated keys from the leader and won't be responsible for
// tracking expiration and distributing new keys themselves, but may become leaders
// later on and will need to know when to update the key.
if (keyRotationIntervalMs > 0) {
DistributedHerder.this.keyExpiration = sessionKey.creationTimestamp() + keyRotationIntervalMs;
}
}
}
@Override
public void onRestartRequest(RestartRequest request) {
log.info("Received and enqueuing {}", request);
synchronized (DistributedHerder.this) {
String connectorName = request.connectorName();
//preserve the highest impact request
pendingRestartRequests.compute(connectorName, (k, existingRequest) -> {
if (existingRequest == null || request.compareTo(existingRequest) > 0) {
log.debug("Overwriting existing {} and enqueuing the higher impact {}", existingRequest, request);
return request;
} else {
log.debug("Preserving existing higher impact {} and ignoring incoming {}", existingRequest, request);
return existingRequest;
}
});
}
member.wakeup();
}
}
class DistributedHerderRequest implements HerderRequest, Comparable {
private final long at;
private final long seq;
private final Callable action;
private final Callback callback;
public DistributedHerderRequest(long at, long seq, Callable action, Callback callback) {
this.at = at;
this.seq = seq;
this.action = action;
this.callback = callback;
}
public Callable action() {
return action;
}
public Callback callback() {
return callback;
}
@Override
public void cancel() {
DistributedHerder.this.requests.remove(this);
}
@Override
public int compareTo(DistributedHerderRequest o) {
final int cmp = Long.compare(at, o.at);
return cmp == 0 ? Long.compare(seq, o.seq) : cmp;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (!(o instanceof DistributedHerderRequest))
return false;
DistributedHerderRequest other = (DistributedHerderRequest) o;
return compareTo(other) == 0;
}
@Override
public int hashCode() {
return Objects.hash(at, seq);
}
}
private static Callback forwardErrorCallback(final Callback callback) {
return (error, result) -> {
if (error != null)
callback.onCompletion(error, null);
};
}
private void updateDeletedConnectorStatus() {
ClusterConfigState snapshot = configBackingStore.snapshot();
Set connectors = snapshot.connectors();
for (String connector : statusBackingStore.connectors()) {
if (!connectors.contains(connector)) {
log.debug("Cleaning status information for connector {}", connector);
onDeletion(connector);
}
}
}
private void updateDeletedTaskStatus() {
ClusterConfigState snapshot = configBackingStore.snapshot();
for (String connector : statusBackingStore.connectors()) {
Set remainingTasks = new HashSet<>(snapshot.tasks(connector));
statusBackingStore.getAll(connector).stream()
.map(TaskStatus::id)
.filter(task -> !remainingTasks.contains(task))
.forEach(this::onDeletion);
}
}
protected HerderMetrics herderMetrics() {
return herderMetrics;
}
// Rebalances are triggered internally from the group member, so these are always executed in the work thread.
public class RebalanceListener implements WorkerRebalanceListener {
private final Time time;
RebalanceListener(Time time) {
this.time = time;
}
@Override
public void onAssigned(ExtendedAssignment assignment, int generation) {
// This callback just logs the info and saves it. The actual response is handled in the main loop, which
// ensures the group member's logic for rebalancing can complete, potentially long-running steps to
// catch up (or backoff if we fail) not executed in a callback, and so we'll be able to invoke other
// group membership actions (e.g., we may need to explicitly leave the group if we cannot handle the
// assigned tasks).
short priorProtocolVersion = currentProtocolVersion;
DistributedHerder.this.currentProtocolVersion = member.currentProtocolVersion();
log.info(
"Joined group at generation {} with protocol version {} and got assignment: {} with rebalance delay: {}",
generation,
DistributedHerder.this.currentProtocolVersion,
assignment,
assignment.delay()
);
synchronized (DistributedHerder.this) {
DistributedHerder.this.assignment = assignment;
DistributedHerder.this.generation = generation;
int delay = assignment.delay();
DistributedHerder.this.scheduledRebalance = delay > 0
? time.milliseconds() + delay
: Long.MAX_VALUE;
boolean requestValidationWasEnabled = internalRequestValidationEnabled(priorProtocolVersion);
boolean requestValidationNowEnabled = internalRequestValidationEnabled(currentProtocolVersion);
if (requestValidationNowEnabled != requestValidationWasEnabled) {
// Internal request verification has been switched on or off; let the user know
if (requestValidationNowEnabled) {
log.info("Internal request validation has been re-enabled");
} else {
log.warn(
"The protocol used by this Connect cluster has been downgraded from '{}' to '{}' and internal request "
+ "validation is now disabled. This is most likely caused by a new worker joining the cluster with an "
+ "older protocol specified for the {} configuration; if this is not intentional, either remove the {} "
+ "configuration from that worker's config file, or change its value to '{}'. If this configuration is "
+ "left as-is, the cluster will be insecure; for more information, see KIP-507: "
+ "https://cwiki.apache.org/confluence/display/KAFKA/KIP-507%3A+Securing+Internal+Connect+REST+Endpoints",
ConnectProtocolCompatibility.fromProtocolVersion(priorProtocolVersion),
ConnectProtocolCompatibility.fromProtocolVersion(DistributedHerder.this.currentProtocolVersion),
DistributedConfig.CONNECT_PROTOCOL_CONFIG,
DistributedConfig.CONNECT_PROTOCOL_CONFIG,
ConnectProtocolCompatibility.SESSIONED.name()
);
}
}
rebalanceResolved = false;
herderMetrics.rebalanceStarted(time.milliseconds());
}
// Delete the statuses of all connectors and tasks removed prior to the start of this rebalance. This
// has to be done after the rebalance completes to avoid race conditions as the previous generation
// attempts to change the state to UNASSIGNED after tasks have been stopped.
if (isLeader()) {
updateDeletedConnectorStatus();
updateDeletedTaskStatus();
}
// We *must* interrupt any poll() call since this could occur when the poll starts, and we might then
// sleep in the poll() for a long time. Forcing a wakeup ensures we'll get to process this event in the
// main thread.
member.wakeup();
}
@Override
public void onRevoked(String leader, Collection connectors, Collection tasks) {
// Note that since we don't reset the assignment, we don't revoke leadership here. During a rebalance,
// it is still important to have a leader that can write configs, offsets, etc.
if (rebalanceResolved || currentProtocolVersion >= CONNECT_PROTOCOL_V1) {
List> callables = new ArrayList<>();
for (final String connectorName : connectors) {
callables.add(getConnectorStoppingCallable(connectorName));
}
// TODO: We need to at least commit task offsets, but if we could commit offsets & pause them instead of
// stopping them then state could continue to be reused when the task remains on this worker. For example,
// this would avoid having to close a connection and then reopen it when the task is assigned back to this
// worker again.
for (final ConnectorTaskId taskId : tasks) {
callables.add(getTaskStoppingCallable(taskId));
}
// The actual timeout for graceful task/connector stop is applied in worker's
// stopAndAwaitTask/stopAndAwaitConnector methods.
startAndStop(callables);
log.info("Finished stopping tasks in preparation for rebalance");
synchronized (DistributedHerder.this) {
log.debug("Removing connectors from running assignment {}", connectors);
runningAssignment.connectors().removeAll(connectors);
log.debug("Removing tasks from running assignment {}", tasks);
runningAssignment.tasks().removeAll(tasks);
}
if (isTopicTrackingEnabled) {
// Send tombstones to reset active topics for removed connectors only after
// connectors and tasks have been stopped, or these tombstones will be overwritten
resetActiveTopics(connectors, tasks);
}
// Ensure that all status updates have been pushed to the storage system before rebalancing.
// Otherwise, we may inadvertently overwrite the state with a stale value after the rebalance
// completes.
statusBackingStore.flush();
log.info("Finished flushing status backing store in preparation for rebalance");
} else {
log.info("Wasn't able to resume work after last rebalance, can skip stopping connectors and tasks");
}
}
private void resetActiveTopics(Collection connectors, Collection tasks) {
connectors.stream()
.filter(connectorName -> !configState.contains(connectorName))
.forEach(DistributedHerder.this::resetConnectorActiveTopics);
tasks.stream()
.map(ConnectorTaskId::connector)
.distinct()
.filter(connectorName -> !configState.contains(connectorName))
.forEach(DistributedHerder.this::resetConnectorActiveTopics);
}
}
class HerderMetrics {
private final MetricGroup metricGroup;
private final Sensor rebalanceCompletedCounts;
private final Sensor rebalanceTime;
private volatile long lastRebalanceCompletedAtMillis = Long.MIN_VALUE;
private volatile boolean rebalancing = false;
private volatile long rebalanceStartedAtMillis = 0L;
public HerderMetrics(ConnectMetrics connectMetrics) {
ConnectMetricsRegistry registry = connectMetrics.registry();
metricGroup = connectMetrics.group(registry.workerRebalanceGroupName());
metricGroup.addValueMetric(registry.connectProtocol, now ->
ConnectProtocolCompatibility.fromProtocolVersion(member.currentProtocolVersion()).name()
);
metricGroup.addValueMetric(registry.leaderName, now -> leaderUrl());
metricGroup.addValueMetric(registry.epoch, now -> (double) generation);
metricGroup.addValueMetric(registry.rebalanceMode, now -> rebalancing ? 1.0d : 0.0d);
rebalanceCompletedCounts = metricGroup.sensor("completed-rebalance-count");
rebalanceCompletedCounts.add(metricGroup.metricName(registry.rebalanceCompletedTotal), new CumulativeSum());
rebalanceTime = metricGroup.sensor("rebalance-time");
rebalanceTime.add(metricGroup.metricName(registry.rebalanceTimeMax), new Max());
rebalanceTime.add(metricGroup.metricName(registry.rebalanceTimeAvg), new Avg());
metricGroup.addValueMetric(registry.rebalanceTimeSinceLast, now ->
lastRebalanceCompletedAtMillis == Long.MIN_VALUE ? Double.POSITIVE_INFINITY : (double) (now - lastRebalanceCompletedAtMillis));
}
void close() {
metricGroup.close();
}
void rebalanceStarted(long now) {
rebalanceStartedAtMillis = now;
rebalancing = true;
}
void rebalanceSucceeded(long now) {
long duration = Math.max(0L, now - rebalanceStartedAtMillis);
rebalancing = false;
rebalanceCompletedCounts.record(1.0);
rebalanceTime.record(duration);
lastRebalanceCompletedAtMillis = now;
}
protected MetricGroup metricGroup() {
return metricGroup;
}
}
}