szetszwo commented on code in PR #733:
URL: https://github.com/apache/ratis/pull/733#discussion_r962703943
##########
ratis-common/src/main/java/org/apache/ratis/util/TimeoutScheduler.java:
##########
@@ -84,7 +84,10 @@ ScheduledFuture<?> schedule(Runnable task, Supplier<String>
name, TimeDuration t
private static ScheduledThreadPoolExecutor newExecutor() {
LOG.debug("new ScheduledThreadPoolExecutor");
- final ScheduledThreadPoolExecutor e = new ScheduledThreadPoolExecutor(1,
(ThreadFactory) Daemon::new);
+ AtomicInteger count = new AtomicInteger(0);
Review Comment:
It should be private static final:
```java
private static final AtomicInteger COUNT = new AtomicInteger();
```
##########
ratis-server/src/main/java/org/apache/ratis/server/impl/RaftServerImpl.java:
##########
@@ -97,14 +98,31 @@
class RaftServerImpl implements RaftServer.Division,
RaftServerProtocol, RaftServerAsynchronousProtocol,
- RaftClientProtocol, RaftClientAsynchronousProtocol{
+ RaftClientProtocol, RaftClientAsynchronousProtocol, ErrorRecorded {
private static final String CLASS_NAME =
JavaUtils.getClassSimpleName(RaftServerImpl.class);
static final String REQUEST_VOTE = CLASS_NAME + ".requestVote";
static final String APPEND_ENTRIES = CLASS_NAME + ".appendEntries";
static final String INSTALL_SNAPSHOT = CLASS_NAME + ".installSnapshot";
static final String LOG_SYNC = APPEND_ENTRIES + ".logComplete";
static final String START_LEADER_ELECTION = CLASS_NAME +
".startLeaderElection";
+ private Throwable throwable;
+
+ @Override
+ public void setError(Throwable t) {
+ throwable = t;
+ LOG.error("Server transitioning to EXCEPTION state due to", t);
+ // TODO(jiacheng): will the server keep serving or just die itself?
Review Comment:
We should let the application decide. Therefore, we should pass an
`UncaughtExceptionHandler` from the application.
##########
ratis-common/src/main/java/org/apache/ratis/util/ErrorRecorded.java:
##########
@@ -0,0 +1,30 @@
+/*
+ * 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.ratis.util;
+
+import javax.annotation.Nullable;
+
+/**
+ * An internal error will be recorded so it can be later retrieved for report
or recovery.
+ */
+public interface ErrorRecorded {
Review Comment:
Pass a `UncaughtExceptionHandler` instead of adding this interface.
##########
ratis-common/src/main/java/org/apache/ratis/util/Daemon.java:
##########
@@ -17,24 +17,76 @@
*/
package org.apache.ratis.util;
+import javax.annotation.Nullable;
+import java.util.concurrent.atomic.AtomicReference;
+
public class Daemon extends Thread {
{
setDaemon(true);
}
- /** Construct a daemon thread. */
+ /** If the thread meets an uncaught exception, this field will be set. */
+ private final AtomicReference<Throwable> throwable = new
AtomicReference<>(null);
+ private ErrorRecorded statedServer;
+
+ /** Construct a daemon thread with no arguments, left only for extension. */
public Daemon() {
super();
+ setUncaughtExceptionHandler((thread, t) -> {
+ onError(t);
+ });
+ }
+
+ /** Construct a daemon thread with flexible arguments. */
+ public Daemon(Builder builder) {
+ super(builder.runnable);
+ setName(builder.name);
+ this.statedServer = builder.statedServer;
+ setUncaughtExceptionHandler((thread, t) -> {
+ onError(t);
+ });
+ }
+
+ /**
+ * This will be invoked on uncaught exceptions.
+ * Necessary bookkeeping or graceful exit logics should be put here.
+ *
+ * @param t the crashing error
+ */
+ public void onError(Throwable t) {
+ throwable.set(t);
+ if (statedServer != null) {
+ // Rely on the server to log
+ statedServer.setError(t);
+ }
}
- /** Construct a daemon thread with the given runnable. */
- public Daemon(Runnable runnable) {
- this(runnable, runnable.toString());
+ @Nullable
+ public Throwable getError() {
+ return throwable.get();
}
- /** Construct a daemon thread with the given runnable. */
- public Daemon(Runnable runnable, String name) {
- super(runnable);
- this.setName(name);
+ public static class Builder {
+ private final String name;
+ private Runnable runnable;
+ private ErrorRecorded statedServer;
Review Comment:
Let's pass an `UncaughtExceptionHandler` instead of adding ErrorRecorded.
##########
ratis-server/src/main/java/org/apache/ratis/server/impl/RaftServerProxy.java:
##########
@@ -407,6 +426,7 @@ public void close() {
try {
getServerRpc().close();
} catch(IOException ignored) {
+ // TODO(jiacheng): transition state to EXCEPTION here?
Review Comment:
When it is in CLOSING state, it must transit to CLOSED but won't transit to
EXCEPTION. CLOSING must handle the exceptions, if there are any.
##########
ratis-common/src/main/java/org/apache/ratis/util/Daemon.java:
##########
@@ -17,24 +17,76 @@
*/
package org.apache.ratis.util;
+import javax.annotation.Nullable;
+import java.util.concurrent.atomic.AtomicReference;
+
public class Daemon extends Thread {
{
setDaemon(true);
}
- /** Construct a daemon thread. */
+ /** If the thread meets an uncaught exception, this field will be set. */
+ private final AtomicReference<Throwable> throwable = new
AtomicReference<>(null);
+ private ErrorRecorded statedServer;
+
+ /** Construct a daemon thread with no arguments, left only for extension. */
public Daemon() {
super();
+ setUncaughtExceptionHandler((thread, t) -> {
+ onError(t);
+ });
+ }
+
+ /** Construct a daemon thread with flexible arguments. */
+ public Daemon(Builder builder) {
+ super(builder.runnable);
+ setName(builder.name);
+ this.statedServer = builder.statedServer;
+ setUncaughtExceptionHandler((thread, t) -> {
+ onError(t);
+ });
+ }
+
+ /**
+ * This will be invoked on uncaught exceptions.
+ * Necessary bookkeeping or graceful exit logics should be put here.
+ *
+ * @param t the crashing error
+ */
+ public void onError(Throwable t) {
+ throwable.set(t);
+ if (statedServer != null) {
+ // Rely on the server to log
+ statedServer.setError(t);
+ }
}
- /** Construct a daemon thread with the given runnable. */
- public Daemon(Runnable runnable) {
- this(runnable, runnable.toString());
+ @Nullable
+ public Throwable getError() {
+ return throwable.get();
}
- /** Construct a daemon thread with the given runnable. */
- public Daemon(Runnable runnable, String name) {
- super(runnable);
- this.setName(name);
+ public static class Builder {
+ private final String name;
+ private Runnable runnable;
+ private ErrorRecorded statedServer;
+
+ public Builder(String name) {
Review Comment:
Instead of adding a constructor, please add
```java
/** @return a {@link Builder}. */
static Builder newBuilder() {
return new Builder();
}
```
##########
ratis-server/src/main/java/org/apache/ratis/server/impl/RaftServerImpl.java:
##########
@@ -97,14 +98,31 @@
class RaftServerImpl implements RaftServer.Division,
RaftServerProtocol, RaftServerAsynchronousProtocol,
- RaftClientProtocol, RaftClientAsynchronousProtocol{
+ RaftClientProtocol, RaftClientAsynchronousProtocol, ErrorRecorded {
private static final String CLASS_NAME =
JavaUtils.getClassSimpleName(RaftServerImpl.class);
static final String REQUEST_VOTE = CLASS_NAME + ".requestVote";
static final String APPEND_ENTRIES = CLASS_NAME + ".appendEntries";
static final String INSTALL_SNAPSHOT = CLASS_NAME + ".installSnapshot";
static final String LOG_SYNC = APPEND_ENTRIES + ".logComplete";
static final String START_LEADER_ELECTION = CLASS_NAME +
".startLeaderElection";
+ private Throwable throwable;
+
+ @Override
+ public void setError(Throwable t) {
+ throwable = t;
+ LOG.error("Server transitioning to EXCEPTION state due to", t);
+ // TODO(jiacheng): will the server keep serving or just die itself?
+ // What is the cleanup I should consider?
+ lifeCycle.transition(LifeCycle.State.EXCEPTION);
Review Comment:
Pass an `UncaughtExceptionHandler`.
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