Mirror/MarginaliaSearch
1
0
Fork 0
mirror of https://github.com/MarginaliaSearch/MarginaliaSearch.git synced 2025-02-23 21:18:58 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

(mqfsm) Abortable state machine

Browse Source
This commit is contained in:
Viktor Lofgren 2023-07-15 14:11:48 +02:00
parent cdae74d395
commit 5ec10634d8
4 changed files with 46 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
code/common/message-queue/src/main/java/nu/marginalia/mq/MessageQueueFactory.java
View File

@ -26,12 +26,12 @@ public class MessageQueueFactory {
}
public MqInboxIf createAsynchronousInbox(String inboxName, UUID instanceUUID)
public MqAsynchronousInbox createAsynchronousInbox(String inboxName, UUID instanceUUID)
{
return new MqAsynchronousInbox(persistence, inboxName, instanceUUID);
}
public MqInboxIf createSynchronousInbox(String inboxName, UUID instanceUUID)
public MqSynchronousInbox createSynchronousInbox(String inboxName, UUID instanceUUID)
{
return new MqSynchronousInbox(persistence, inboxName, instanceUUID);
}

37
code/common/message-queue/src/main/java/nu/marginalia/mq/inbox/MqSynchronousInbox.java
View File

@ -7,10 +7,9 @@ import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.Collection;
import java.util.List;
import java.util.UUID;
import java.util.*;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.TimeUnit;
/** Message queue inbox that responds to a single message at a time
@ -29,6 +28,7 @@ public class MqSynchronousInbox implements MqInboxIf {
private final List<MqSubscription> eventSubscribers = new ArrayList<>();
private Thread pollDbThread;
private ExecutorService executorService = Executors.newSingleThreadExecutor();
public MqSynchronousInbox(MqPersistence persistence,
String inboxName,
@ -74,6 +74,8 @@ public class MqSynchronousInbox implements MqInboxIf {
run = false;
pollDbThread.join();
executorService.shutdown();
executorService.awaitTermination(10, TimeUnit.SECONDS);
}
@ -101,7 +103,8 @@ public class MqSynchronousInbox implements MqInboxIf {
try {
subscriber.onNotification(msg);
updateMessageState(msg, MqMessageState.OK);
} catch (Exception ex) {
}
catch (Exception ex) {
logger.error("Message Queue subscriber threw exception", ex);
updateMessageState(msg, MqMessageState.ERR);
}
@ -134,6 +137,7 @@ public class MqSynchronousInbox implements MqInboxIf {
}
}
private volatile java.util.concurrent.Future<?> currentTask = null;
public void pollDb() {
try {
for (long tick = 1; run; tick++) {
@ -141,7 +145,18 @@ public class MqSynchronousInbox implements MqInboxIf {
var messages = pollInbox(tick);
for (var msg : messages) {
handleMessage(msg);
// Handle message in a separate thread but wait for that thread, so we can interrupt that thread
// without interrupting the polling thread and shutting down the inbox completely
try {
currentTask = executorService.submit(() -> handleMessage(msg));
currentTask.get();
}
catch (Exception ex) {
logger.error("Inbox task was aborted", ex);
}
finally {
currentTask = null;
}
}
if (messages.isEmpty()) {
@ -154,6 +169,16 @@ public class MqSynchronousInbox implements MqInboxIf {
}
}
/** Attempt to abort the current task using an interrupt */
public void abortCurrentTask() {
var task = currentTask; // capture the value to avoid race conditions with the
// polling thread between the check and the interrupt
if (task != null) {
task.cancel(true);
}
}
private void handleMessage(MqMessage msg) {
logger.info("Notifying subscribers of msg {}", msg.msgId());

8
code/common/message-queue/src/main/java/nu/marginalia/mqsm/StateMachine.java
View File

@ -6,6 +6,7 @@ import nu.marginalia.mq.MqMessageState;
import nu.marginalia.mq.inbox.MqInboxIf;
import nu.marginalia.mq.inbox.MqInboxResponse;
import nu.marginalia.mq.inbox.MqSubscription;
import nu.marginalia.mq.inbox.MqSynchronousInbox;
import nu.marginalia.mq.outbox.MqOutbox;
import nu.marginalia.mqsm.graph.ResumeBehavior;
import nu.marginalia.mqsm.graph.AbstractStateGraph;
@ -25,7 +26,7 @@ import java.util.function.BiConsumer;
public class StateMachine {
private final Logger logger = LoggerFactory.getLogger(StateMachine.class);
private final MqInboxIf smInbox;
private final MqSynchronousInbox smInbox;
private final MqOutbox smOutbox;
private final String queueName;
@ -291,6 +292,11 @@ public class StateMachine {
// Add a state transition to the final state
smOutbox.notify(abortMsgId, finalState.name(), "");
// Dislodge the current task with an interrupt.
// It's actually fine if we accidentally interrupt the wrong thread
// (i.e. the abort task), since it shouldn't be doing anything interruptable
smInbox.abortCurrentTask();
}
private class StateEventSubscription implements MqSubscription {

7
code/common/message-queue/src/main/java/nu/marginalia/mqsm/graph/AbstractStateGraph.java
View File

@ -124,7 +124,12 @@ public abstract class AbstractStateGraph {
if (ex instanceof ControlFlowException cfe) {
return stateFactory.transition(cfe.getState(), cfe.getPayload());
} else {
}
else if (ex instanceof InterruptedException intE) {
logger.error("State execution was interrupted " + state);
return StateTransition.to("ERR", "Execution interrupted");
}
else {
logger.error("Error in state invocation " + state, ex);
return StateTransition.to("ERROR",
"Exception: " + ex.getClass().getSimpleName() + "/" + ex.getMessage());