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This module contains code to support integration with Amazon Web Services.
It also declares the dependencies needed to work with AWS services.
/*
* 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.hadoop.fs.s3a;
import java.io.IOException;
import java.io.InterruptedIOException;
import java.util.Optional;
import javax.annotation.Nullable;
import com.amazonaws.AmazonClientException;
import com.amazonaws.SdkBaseException;
import com.google.common.base.Preconditions;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.apache.commons.lang3.StringUtils;
import org.apache.hadoop.io.retry.RetryPolicy;
/**
* Class to provide lambda expression invocation of AWS operations.
*
* The core retry logic is in
* {@link #retryUntranslated(String, boolean, Retried, Operation)};
* the other {@code retry() and retryUntranslated()} calls are wrappers.
*
* The static {@link #once(String, String, Operation)} and
* {@link #once(String, String, VoidOperation)} calls take an operation and
* return it with AWS exceptions translated to IOEs of some form.
*
* The retry logic on a failure is defined by the retry policy passed in
* the constructor; the standard retry policy is {@link S3ARetryPolicy},
* though others may be used.
*
* The constructor also takes two {@link Retried} callbacks.
* The {@code caughtCallback} is called whenever an exception (IOE or AWS)
* is caught, before the retry processing looks at it.
* The {@code retryCallback} is invoked after a retry is scheduled
* but before the sleep.
* These callbacks can be used for reporting and incrementing statistics.
*
* The static {@link #quietly(String, String, VoidOperation)} and
* {@link #quietlyEval(String, String, Operation)} calls exist to take any
* operation and quietly catch and log at debug. The return value of
* {@link #quietlyEval(String, String, Operation)} is a java 8 optional,
* which can then be used in java8-expressions.
*/
public class Invoker {
private static final Logger LOG = LoggerFactory.getLogger(Invoker.class);
/**
* Retry policy to use.
*/
private final RetryPolicy retryPolicy;
/**
* Default retry handler.
*/
private final Retried retryCallback;
/**
* Instantiate.
* @param retryPolicy retry policy for all operations.
* @param retryCallback standard retry policy
*/
public Invoker(
RetryPolicy retryPolicy,
Retried retryCallback) {
this.retryPolicy = retryPolicy;
this.retryCallback = retryCallback;
}
public RetryPolicy getRetryPolicy() {
return retryPolicy;
}
public Retried getRetryCallback() {
return retryCallback;
}
/**
* Execute a function, translating any exception into an IOException.
* @param action action to execute (used in error messages)
* @param path path of work (used in error messages)
* @param operation operation to execute
* @param type of return value
* @return the result of the function call
* @throws IOException any IOE raised, or translated exception
*/
@Retries.OnceTranslated
public static T once(String action, String path, Operation operation)
throws IOException {
try {
return operation.execute();
} catch (AmazonClientException e) {
throw S3AUtils.translateException(action, path, e);
}
}
/**
* Execute an operation with no result.
* @param action action to execute (used in error messages)
* @param path path of work (used in error messages)
* @param operation operation to execute
* @throws IOException any IOE raised, or translated exception
*/
@Retries.OnceTranslated
public static void once(String action, String path, VoidOperation operation)
throws IOException {
once(action, path,
() -> {
operation.execute();
return null;
});
}
/**
* Execute an operation and ignore all raised IOExceptions; log at INFO;
* full stack only at DEBUG.
* @param log log to use.
* @param action action to include in log
* @param path optional path to include in log
* @param operation operation to execute
* @param type of operation
*/
public static void ignoreIOExceptions(
Logger log,
String action,
String path,
Operation operation) {
try {
once(action, path, operation);
} catch (IOException e) {
String description = toDescription(action, path);
String error = e.toString();
log.info("{}: {}", description, error);
log.debug("{}", description, e);
}
}
/**
* Execute an operation and ignore all raised IOExceptions; log at INFO;
* full stack only at DEBUG.
* @param log log to use.
* @param action action to include in log
* @param path optional path to include in log
* @param operation operation to execute
*/
public static void ignoreIOExceptions(
Logger log,
String action,
String path,
VoidOperation operation) {
ignoreIOExceptions(log, action, path,
() -> {
operation.execute();
return null;
});
}
/**
* Execute a void operation with retry processing.
* @param action action to execute (used in error messages)
* @param path path of work (used in error messages)
* @param idempotent does the operation have semantics
* which mean that it can be retried even if was already executed?
* @param retrying callback on retries
* @param operation operation to execute
* @throws IOException any IOE raised, or translated exception
*/
@Retries.RetryTranslated
public void retry(String action,
String path,
boolean idempotent,
Retried retrying,
VoidOperation operation)
throws IOException {
retry(action, path, idempotent, retrying,
() -> {
operation.execute();
return null;
});
}
/**
* Execute a void operation with the default retry callback invoked.
* @param action action to execute (used in error messages)
* @param path path of work (used in error messages)
* @param idempotent does the operation have semantics
* which mean that it can be retried even if was already executed?
* @param operation operation to execute
* @throws IOException any IOE raised, or translated exception
*/
@Retries.RetryTranslated
public void retry(String action,
String path,
boolean idempotent,
VoidOperation operation)
throws IOException {
retry(action, path, idempotent, retryCallback, operation);
}
/**
* Execute a function with the default retry callback invoked.
* @param action action to execute (used in error messages)
* @param path path of work (used in error messages)
* @param idempotent does the operation have semantics
* which mean that it can be retried even if was already executed?
* @param operation operation to execute
* @param type of return value
* @return the result of the call
* @throws IOException any IOE raised, or translated exception
*/
@Retries.RetryTranslated
public T retry(String action,
@Nullable String path,
boolean idempotent,
Operation operation)
throws IOException {
return retry(action, path, idempotent, retryCallback, operation);
}
/**
* Execute a function with retry processing.
* Uses {@link #once(String, String, Operation)} as the inner
* invocation mechanism before retry logic is performed.
* @param type of return value
* @param action action to execute (used in error messages)
* @param path path of work (used in error messages)
* @param idempotent does the operation have semantics
* which mean that it can be retried even if was already executed?
* @param retrying callback on retries
* @param operation operation to execute
* @return the result of the call
* @throws IOException any IOE raised, or translated exception
*/
@Retries.RetryTranslated
public T retry(
String action,
@Nullable String path,
boolean idempotent,
Retried retrying,
Operation operation)
throws IOException {
return retryUntranslated(
toDescription(action, path),
idempotent,
retrying,
() -> once(action, path, operation));
}
/**
* Execute a function with retry processing and no translation.
* and the default retry callback.
* @param text description for the catching callback
* @param idempotent does the operation have semantics
* which mean that it can be retried even if was already executed?
* @param operation operation to execute
* @param type of return value
* @return the result of the call
* @throws IOException any IOE raised
* @throws RuntimeException any Runtime exception raised
*/
@Retries.RetryRaw
public T retryUntranslated(
String text,
boolean idempotent,
Operation operation) throws IOException {
return retryUntranslated(text, idempotent,
retryCallback, operation);
}
/**
* Execute a function with retry processing: AWS SDK Exceptions
* are not translated.
* This is method which the others eventually invoke.
* @param type of return value
* @param text text to include in messages
* @param idempotent does the operation have semantics
* which mean that it can be retried even if was already executed?
* @param retrying callback on retries
* @param operation operation to execute
* @return the result of the call
* @throws IOException any IOE raised
* @throws SdkBaseException any AWS exception raised
* @throws RuntimeException : these are never caught and retries.
*/
@Retries.RetryRaw
public T retryUntranslated(
String text,
boolean idempotent,
Retried retrying,
Operation operation) throws IOException {
Preconditions.checkArgument(retrying != null, "null retrying argument");
int retryCount = 0;
Exception caught;
RetryPolicy.RetryAction retryAction;
boolean shouldRetry;
do {
try {
if (retryCount > 0) {
LOG.debug("retry #{}", retryCount);
}
// execute the operation, returning if successful
return operation.execute();
} catch (IOException | SdkBaseException e) {
caught = e;
}
// you only get here if the operation didn't complete
// normally, hence caught != null
// translate the exception into an IOE for the retry logic
IOException translated;
if (caught instanceof IOException) {
translated = (IOException) caught;
} else {
translated = S3AUtils.translateException(text, "",
(SdkBaseException)caught);
}
try {
// decide action base on operation, invocation count, etc
retryAction = retryPolicy.shouldRetry(translated, retryCount, 0,
idempotent);
// is it a retry operation?
shouldRetry = retryAction.action.equals(
RetryPolicy.RetryAction.RETRY.action);
if (shouldRetry) {
// notify the callback
retrying.onFailure(text, translated, retryCount, idempotent);
// then sleep for the policy delay
Thread.sleep(retryAction.delayMillis);
}
// increment the retry count
retryCount++;
} catch (InterruptedException e) {
// sleep was interrupted
// change the exception
caught = new InterruptedIOException("Interrupted");
caught.initCause(e);
// no retry
shouldRetry = false;
// and re-interrupt the thread
Thread.currentThread().interrupt();
} catch (Exception e) {
// The retry policy raised an exception
// log that something happened
LOG.warn("{}: exception in retry processing", text, e);
// and fail the execution with the last execution exception.
shouldRetry = false;
}
} while (shouldRetry);
if (caught instanceof IOException) {
throw (IOException) caught;
} else {
throw (SdkBaseException) caught;
}
}
/**
* Execute an operation; any exception raised is simply caught and
* logged at debug.
* @param action action to execute
* @param path path (for exception construction)
* @param operation operation
*/
public static void quietly(String action,
String path,
VoidOperation operation) {
try {
once(action, path, operation);
} catch (Exception e) {
LOG.debug("Action {} failed", action, e);
}
}
/**
* Execute an operation; any exception raised is caught and
* logged at debug.
* The result is only non-empty if the operation succeeded
* @param type to return
* @param action action to execute
* @param path path (for exception construction)
* @param operation operation
* @return the result of a successful operation
*/
public static Optional quietlyEval(String action,
String path,
Operation operation) {
try {
return Optional.of(once(action, path, operation));
} catch (Exception e) {
LOG.debug("Action {} failed", action, e);
return Optional.empty();
}
}
/**
* Take an action and path and produce a string for logging.
* @param action action
* @param path path (may be null or empty)
* @return string for logs
*/
private static String toDescription(String action, @Nullable String path) {
return action +
(StringUtils.isNotEmpty(path) ? (" on " + path) : "");
}
/**
* Arbitrary operation throwing an IOException.
* @param return type
*/
@FunctionalInterface
public interface Operation {
T execute() throws IOException;
}
/**
* Void operation which may raise an IOException.
*/
@FunctionalInterface
public interface VoidOperation {
void execute() throws IOException;
}
/**
* Callback for retry and notification operations.
* Even if the interface is throwing up "raw" exceptions, this handler
* gets the translated one.
*/
@FunctionalInterface
public interface Retried {
/**
* Retry event in progress (before any sleep).
* @param text text passed in to the retry() Call.
* @param exception the caught (and possibly translated) exception.
* @param retries number of retries so far
* @param idempotent is the request idempotent.
*/
void onFailure(
String text,
IOException exception,
int retries,
boolean idempotent);
}
/**
* No op for a retrying callback.
*/
public static final Retried NO_OP = new Retried() {
@Override
public void onFailure(String text,
IOException exception,
int retries,
boolean idempotent) {
}
};
/**
* Log summary at info, full stack at debug.
*/
public static final Retried LOG_EVENT = new Retried() {
@Override
public void onFailure(String text,
IOException exception,
int retries,
boolean idempotent) {
LOG.debug("{}: " + exception, text);
if (retries == 1) {
// stack on first attempt, to keep noise down
LOG.debug("{}: " + exception, text, exception);
}
}
};
}