From 03c4491d890499169bbe33432af1ed16e61e44bc Mon Sep 17 00:00:00 2001 From: Jing Zhao Date: Mon, 16 May 2016 15:23:36 -0700 Subject: [PATCH] HADOOP-13146. Refactor RetryInvocationHandler. Contributed by Tsz Wo Nicholas Sze. --- .../io/retry/FailoverProxyProvider.java | 11 + .../io/retry/RetryInvocationHandler.java | 353 +++++++++--------- .../hadoop/io/retry/TestRetryProxy.java | 67 +--- 3 files changed, 212 insertions(+), 219 deletions(-) diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/retry/FailoverProxyProvider.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/retry/FailoverProxyProvider.java index 5acb936aad5..c73e0837721 100644 --- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/retry/FailoverProxyProvider.java +++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/retry/FailoverProxyProvider.java @@ -37,10 +37,21 @@ public interface FailoverProxyProvider extends Closeable { * provides information for debugging purposes. */ public final String proxyInfo; + public ProxyInfo(T proxy, String proxyInfo) { this.proxy = proxy; this.proxyInfo = proxyInfo; } + + public String getString(String methodName) { + return proxy.getClass().getSimpleName() + "." + methodName + + " over " + proxyInfo; + } + + @Override + public String toString() { + return proxy.getClass().getSimpleName() + " over " + proxyInfo; + } } /** diff --git a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/retry/RetryInvocationHandler.java b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/retry/RetryInvocationHandler.java index d57dc84ffc9..300d0c2ab5b 100644 --- a/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/retry/RetryInvocationHandler.java +++ b/hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/io/retry/RetryInvocationHandler.java @@ -17,49 +17,137 @@ */ package org.apache.hadoop.io.retry; -import java.io.IOException; -import java.lang.reflect.InvocationHandler; -import java.lang.reflect.InvocationTargetException; -import java.lang.reflect.Method; -import java.lang.reflect.Proxy; -import java.util.Collections; -import java.util.LinkedList; -import java.util.List; -import java.util.Map; -import java.util.concurrent.atomic.AtomicLong; - +import com.google.common.annotations.VisibleForTesting; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.classification.InterfaceAudience; import org.apache.hadoop.io.retry.FailoverProxyProvider.ProxyInfo; import org.apache.hadoop.io.retry.RetryPolicy.RetryAction; -import org.apache.hadoop.ipc.Client; +import org.apache.hadoop.ipc.*; import org.apache.hadoop.ipc.Client.ConnectionId; -import org.apache.hadoop.ipc.ProtocolTranslator; -import org.apache.hadoop.ipc.RPC; -import org.apache.hadoop.ipc.RpcConstants; -import org.apache.hadoop.ipc.RpcInvocationHandler; -import com.google.common.annotations.VisibleForTesting; +import java.io.IOException; +import java.lang.reflect.InvocationHandler; +import java.lang.reflect.InvocationTargetException; +import java.lang.reflect.Method; +import java.lang.reflect.Proxy; +import java.util.Arrays; +import java.util.Collections; +import java.util.Map; /** - * This class implements RpcInvocationHandler and supports retry on the client - * side. + * A {@link RpcInvocationHandler} which supports client side retry . */ @InterfaceAudience.Private public class RetryInvocationHandler implements RpcInvocationHandler { public static final Log LOG = LogFactory.getLog(RetryInvocationHandler.class); - private final FailoverProxyProvider proxyProvider; - /** - * The number of times the associated proxyProvider has ever been failed over. - */ - private long proxyProviderFailoverCount = 0; + private static class Counters { + /** Counter for retries. */ + private int retries; + /** Counter for method invocation has been failed over. */ + private int failovers; + } + + private static class ProxyDescriptor { + private final FailoverProxyProvider fpp; + /** Count the associated proxy provider has ever been failed over. */ + private long failoverCount = 0; + + private ProxyInfo proxyInfo; + + ProxyDescriptor(FailoverProxyProvider fpp) { + this.fpp = fpp; + this.proxyInfo = fpp.getProxy(); + } + + synchronized ProxyInfo getProxyInfo() { + return proxyInfo; + } + + synchronized T getProxy() { + return proxyInfo.proxy; + } + + synchronized long getFailoverCount() { + return failoverCount; + } + + synchronized void failover(long expectedFailoverCount, Method method) { + // Make sure that concurrent failed invocations only cause a single + // actual failover. + if (failoverCount == expectedFailoverCount) { + fpp.performFailover(proxyInfo.proxy); + failoverCount++; + } else { + LOG.warn("A failover has occurred since the start of " + + proxyInfo.getString(method.getName())); + } + proxyInfo = fpp.getProxy(); + } + + boolean idempotentOrAtMostOnce(Method method) throws NoSuchMethodException { + final Method m = fpp.getInterface() + .getMethod(method.getName(), method.getParameterTypes()); + return m.isAnnotationPresent(Idempotent.class) + || m.isAnnotationPresent(AtMostOnce.class); + } + + void close() throws IOException { + fpp.close(); + } + } + + private static class RetryInfo { + private final long delay; + private final RetryAction failover; + private final RetryAction fail; + + RetryInfo(long delay, RetryAction failover, RetryAction fail) { + this.delay = delay; + this.failover = failover; + this.fail = fail; + } + + static RetryInfo newRetryInfo(RetryPolicy policy, Exception e, + Counters counters, boolean idempotentOrAtMostOnce) throws Exception { + long maxRetryDelay = 0; + RetryAction failover = null; + RetryAction retry = null; + RetryAction fail = null; + + final Iterable exceptions = e instanceof MultiException ? + ((MultiException) e).getExceptions().values() + : Collections.singletonList(e); + for (Exception exception : exceptions) { + final RetryAction a = policy.shouldRetry(exception, + counters.retries, counters.failovers, idempotentOrAtMostOnce); + if (a.action == RetryAction.RetryDecision.FAIL) { + fail = a; + } else { + // must be a retry or failover + if (a.action == RetryAction.RetryDecision.FAILOVER_AND_RETRY) { + failover = a; + } else { + retry = a; + } + if (a.delayMillis > maxRetryDelay) { + maxRetryDelay = a.delayMillis; + } + } + } + + return new RetryInfo(maxRetryDelay, failover, + failover == null && retry == null? fail: null); + } + } + + private final ProxyDescriptor proxyDescriptor; + private volatile boolean hasMadeASuccessfulCall = false; private final RetryPolicy defaultPolicy; private final Map methodNameToPolicyMap; - private ProxyInfo currentProxy; protected RetryInvocationHandler(FailoverProxyProvider proxyProvider, RetryPolicy retryPolicy) { @@ -69,39 +157,40 @@ public class RetryInvocationHandler implements RpcInvocationHandler { protected RetryInvocationHandler(FailoverProxyProvider proxyProvider, RetryPolicy defaultPolicy, Map methodNameToPolicyMap) { - this.proxyProvider = proxyProvider; + this.proxyDescriptor = new ProxyDescriptor<>(proxyProvider); this.defaultPolicy = defaultPolicy; this.methodNameToPolicyMap = methodNameToPolicyMap; - this.currentProxy = proxyProvider.getProxy(); + } + + private RetryPolicy getRetryPolicy(Method method) { + final RetryPolicy policy = methodNameToPolicyMap.get(method.getName()); + return policy != null? policy: defaultPolicy; } @Override public Object invoke(Object proxy, Method method, Object[] args) - throws Throwable { - RetryPolicy policy = methodNameToPolicyMap.get(method.getName()); - if (policy == null) { - policy = defaultPolicy; - } - - // The number of times this method invocation has been failed over. - int invocationFailoverCount = 0; - final boolean isRpc = isRpcInvocation(currentProxy.proxy); + throws Throwable { + final boolean isRpc = isRpcInvocation(proxyDescriptor.getProxy()); final int callId = isRpc? Client.nextCallId(): RpcConstants.INVALID_CALL_ID; - int retries = 0; + return invoke(method, args, isRpc, callId, new Counters()); + } + + private Object invoke(final Method method, final Object[] args, + final boolean isRpc, final int callId, final Counters counters) + throws Throwable { + final RetryPolicy policy = getRetryPolicy(method); + while (true) { // The number of times this invocation handler has ever been failed over, // before this method invocation attempt. Used to prevent concurrent // failed method invocations from triggering multiple failover attempts. - long invocationAttemptFailoverCount; - synchronized (proxyProvider) { - invocationAttemptFailoverCount = proxyProviderFailoverCount; - } + final long failoverCount = proxyDescriptor.getFailoverCount(); if (isRpc) { - Client.setCallIdAndRetryCount(callId, retries); + Client.setCallIdAndRetryCount(callId, counters.retries); } try { - Object ret = invokeMethod(method, args); + final Object ret = invokeMethod(method, args); hasMadeASuccessfulCall = true; return ret; } catch (Exception ex) { @@ -109,153 +198,74 @@ public class RetryInvocationHandler implements RpcInvocationHandler { // If interrupted, do not retry. throw ex; } - boolean isIdempotentOrAtMostOnce = proxyProvider.getInterface() - .getMethod(method.getName(), method.getParameterTypes()) - .isAnnotationPresent(Idempotent.class); - if (!isIdempotentOrAtMostOnce) { - isIdempotentOrAtMostOnce = proxyProvider.getInterface() - .getMethod(method.getName(), method.getParameterTypes()) - .isAnnotationPresent(AtMostOnce.class); - } - List actions = extractActions(policy, ex, retries++, - invocationFailoverCount, isIdempotentOrAtMostOnce); - RetryAction failAction = getFailAction(actions); - if (failAction != null) { - // fail. - if (failAction.reason != null) { - LOG.warn("Exception while invoking " + currentProxy.proxy.getClass() - + "." + method.getName() + " over " + currentProxy.proxyInfo - + ". Not retrying because " + failAction.reason, ex); - } - throw ex; - } else { // retry or failover - // avoid logging the failover if this is the first call on this - // proxy object, and we successfully achieve the failover without - // any flip-flopping - boolean worthLogging = - !(invocationFailoverCount == 0 && !hasMadeASuccessfulCall); - worthLogging |= LOG.isDebugEnabled(); - RetryAction failOverAction = getFailOverAction(actions); - long delay = getDelayMillis(actions); - - if (worthLogging) { - String msg = "Exception while invoking " + method.getName() - + " of class " + currentProxy.proxy.getClass().getSimpleName() - + " over " + currentProxy.proxyInfo; - - if (invocationFailoverCount > 0) { - msg += " after " + invocationFailoverCount + " fail over attempts"; - } - - if (failOverAction != null) { - // failover - msg += ". Trying to fail over " + formatSleepMessage(delay); - } else { - // retry - msg += ". Retrying " + formatSleepMessage(delay); - } - LOG.info(msg, ex); - } - - if (delay > 0) { - Thread.sleep(delay); - } - - if (failOverAction != null) { - // Make sure that concurrent failed method invocations only cause a - // single actual fail over. - synchronized (proxyProvider) { - if (invocationAttemptFailoverCount == proxyProviderFailoverCount) { - proxyProvider.performFailover(currentProxy.proxy); - proxyProviderFailoverCount++; - } else { - LOG.warn("A failover has occurred since the start of this method" - + " invocation attempt."); - } - currentProxy = proxyProvider.getProxy(); - } - invocationFailoverCount++; - } - } + handleException(method, policy, failoverCount, counters, ex); } } } - /** - * Obtain a retry delay from list of RetryActions. - */ - private long getDelayMillis(List actions) { - long retVal = 0; - for (RetryAction action : actions) { - if (action.action == RetryAction.RetryDecision.FAILOVER_AND_RETRY || - action.action == RetryAction.RetryDecision.RETRY) { - if (action.delayMillis > retVal) { - retVal = action.delayMillis; - } + private void handleException(final Method method, final RetryPolicy policy, + final long expectedFailoverCount, final Counters counters, + final Exception ex) throws Exception { + final RetryInfo retryInfo = RetryInfo.newRetryInfo(policy, ex, counters, + proxyDescriptor.idempotentOrAtMostOnce(method)); + counters.retries++; + + if (retryInfo.fail != null) { + // fail. + if (retryInfo.fail.reason != null) { + LOG.warn("Exception while invoking " + + proxyDescriptor.getProxyInfo().getString(method.getName()) + + ". Not retrying because " + retryInfo.fail.reason, ex); } + throw ex; + } + + // retry + final boolean isFailover = retryInfo.failover != null; + + log(method, isFailover, counters.failovers, retryInfo.delay, ex); + + if (retryInfo.delay > 0) { + Thread.sleep(retryInfo.delay); + } + + if (isFailover) { + proxyDescriptor.failover(expectedFailoverCount, method); + counters.failovers++; } - return retVal; } - /** - * Return the first FAILOVER_AND_RETRY action. - */ - private RetryAction getFailOverAction(List actions) { - for (RetryAction action : actions) { - if (action.action == RetryAction.RetryDecision.FAILOVER_AND_RETRY) { - return action; - } + private void log(final Method method, final boolean isFailover, + final int failovers, final long delay, final Exception ex) { + // log info if this has made some successful calls or + // this is not the first failover + final boolean info = hasMadeASuccessfulCall || failovers != 0; + if (!info && !LOG.isDebugEnabled()) { + return; } - return null; - } - /** - * Return the last FAIL action.. only if there are no RETRY actions. - */ - private RetryAction getFailAction(List actions) { - RetryAction fAction = null; - for (RetryAction action : actions) { - if (action.action == RetryAction.RetryDecision.FAIL) { - fAction = action; - } else { - // Atleast 1 RETRY - return null; - } + final StringBuilder b = new StringBuilder() + .append("Exception while invoking ") + .append(proxyDescriptor.getProxyInfo().getString(method.getName())); + if (failovers > 0) { + b.append(" after ").append(failovers).append(" failover attempts"); } - return fAction; - } + b.append(isFailover? ". Trying to failover ": ". Retrying "); + b.append(delay > 0? "after sleeping for " + delay + "ms.": "immediately."); - private List extractActions(RetryPolicy policy, Exception ex, - int i, int invocationFailoverCount, - boolean isIdempotentOrAtMostOnce) - throws Exception { - List actions = new LinkedList<>(); - if (ex instanceof MultiException) { - for (Exception th : ((MultiException) ex).getExceptions().values()) { - actions.add(policy.shouldRetry(th, i, invocationFailoverCount, - isIdempotentOrAtMostOnce)); - } + if (info) { + LOG.info(b.toString(), ex); } else { - actions.add(policy.shouldRetry(ex, i, - invocationFailoverCount, isIdempotentOrAtMostOnce)); + LOG.debug(b.toString(), ex); } - return actions; } - private static String formatSleepMessage(long millis) { - if (millis > 0) { - return "after sleeping for " + millis + "ms."; - } else { - return "immediately."; - } - } - protected Object invokeMethod(Method method, Object[] args) throws Throwable { try { if (!method.isAccessible()) { method.setAccessible(true); } - return method.invoke(currentProxy.proxy, args); + return method.invoke(proxyDescriptor.getProxy(), args); } catch (InvocationTargetException e) { throw e.getCause(); } @@ -275,12 +285,11 @@ public class RetryInvocationHandler implements RpcInvocationHandler { @Override public void close() throws IOException { - proxyProvider.close(); + proxyDescriptor.close(); } @Override //RpcInvocationHandler public ConnectionId getConnectionId() { - return RPC.getConnectionIdForProxy(currentProxy.proxy); + return RPC.getConnectionIdForProxy(proxyDescriptor.getProxy()); } - } diff --git a/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/io/retry/TestRetryProxy.java b/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/io/retry/TestRetryProxy.java index 4137daec54c..41c1be49104 100644 --- a/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/io/retry/TestRetryProxy.java +++ b/hadoop-common-project/hadoop-common/src/test/java/org/apache/hadoop/io/retry/TestRetryProxy.java @@ -18,55 +18,32 @@ package org.apache.hadoop.io.retry; -import static org.apache.hadoop.io.retry.RetryPolicies.RETRY_FOREVER; -import static org.apache.hadoop.io.retry.RetryPolicies.TRY_ONCE_THEN_FAIL; -import static org.apache.hadoop.io.retry.RetryPolicies.retryByException; -import static org.apache.hadoop.io.retry.RetryPolicies.retryByRemoteException; -import static org.apache.hadoop.io.retry.RetryPolicies.retryOtherThanRemoteException; -import static org.apache.hadoop.io.retry.RetryPolicies.retryUpToMaximumCountWithFixedSleep; -import static org.apache.hadoop.io.retry.RetryPolicies.retryUpToMaximumCountWithProportionalSleep; -import static org.apache.hadoop.io.retry.RetryPolicies.retryUpToMaximumTimeWithFixedSleep; -import static org.apache.hadoop.io.retry.RetryPolicies.retryForeverWithFixedSleep; -import static org.apache.hadoop.io.retry.RetryPolicies.exponentialBackoffRetry; - -import static org.mockito.Matchers.any; -import static org.mockito.Matchers.anyBoolean; -import static org.mockito.Matchers.anyInt; -import static org.mockito.Mockito.mock; -import static org.mockito.Mockito.times; -import static org.mockito.Mockito.verify; -import static org.mockito.Mockito.when; - -import static org.junit.Assert.*; - -import java.io.IOException; -import java.util.Collections; -import java.util.Map; -import java.util.concurrent.Callable; -import java.util.concurrent.CountDownLatch; -import java.util.concurrent.ExecutorService; -import java.util.concurrent.Executors; -import java.util.concurrent.Future; -import java.util.concurrent.TimeUnit; -import java.util.concurrent.atomic.AtomicReference; - +import org.apache.hadoop.io.retry.RetryPolicies.*; import org.apache.hadoop.io.retry.RetryPolicy.RetryAction; import org.apache.hadoop.io.retry.RetryPolicy.RetryAction.RetryDecision; -import org.apache.hadoop.io.retry.RetryPolicies.RetryUpToMaximumCountWithFixedSleep; -import org.apache.hadoop.io.retry.RetryPolicies.RetryUpToMaximumTimeWithFixedSleep; -import org.apache.hadoop.io.retry.RetryPolicies.TryOnceThenFail; import org.apache.hadoop.io.retry.UnreliableInterface.FatalException; import org.apache.hadoop.io.retry.UnreliableInterface.UnreliableException; import org.apache.hadoop.ipc.ProtocolTranslator; import org.apache.hadoop.ipc.RemoteException; - +import org.junit.Before; +import org.junit.Test; import org.mockito.invocation.InvocationOnMock; import org.mockito.stubbing.Answer; -import org.junit.Before; -import org.junit.Test; - +import java.io.IOException; import java.lang.reflect.UndeclaredThrowableException; +import java.util.Collections; +import java.util.Map; +import java.util.concurrent.*; +import java.util.concurrent.atomic.AtomicInteger; +import java.util.concurrent.atomic.AtomicReference; + +import static org.apache.hadoop.io.retry.RetryPolicies.*; +import static org.junit.Assert.*; +import static org.mockito.Matchers.any; +import static org.mockito.Matchers.anyBoolean; +import static org.mockito.Matchers.anyInt; +import static org.mockito.Mockito.*; public class TestRetryProxy { @@ -131,25 +108,21 @@ public class TestRetryProxy { final UnreliableInterface unreliable = (UnreliableInterface) RetryProxy.create(UnreliableInterface.class, unreliableImpl, RETRY_FOREVER); assertTrue(RetryInvocationHandler.isRpcInvocation(unreliable)); - + + final AtomicInteger count = new AtomicInteger(); // Embed the proxy in ProtocolTranslator ProtocolTranslator xlator = new ProtocolTranslator() { - int count = 0; @Override public Object getUnderlyingProxyObject() { - count++; + count.getAndIncrement(); return unreliable; } - @Override - public String toString() { - return "" + count; - } }; // For a proxy wrapped in ProtocolTranslator method should return true assertTrue(RetryInvocationHandler.isRpcInvocation(xlator)); // Ensure underlying proxy was looked at - assertEquals(xlator.toString(), "1"); + assertEquals(1, count.get()); // For non-proxy the method must return false assertFalse(RetryInvocationHandler.isRpcInvocation(new Object()));