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/**
* Copyright Microsoft Corporation
*
* Licensed 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 com.microsoft.azure.storage.core;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.util.Date;
import java.util.Map.Entry;
import java.util.concurrent.TimeoutException;
import com.microsoft.azure.storage.*;
/**
* RESERVED FOR INTERNAL USE. A class that handles execution of StorageOperations and enforces retry policies.
*/
public final class ExecutionEngine {
/**
* Executes an operation and enforces a retrypolicy to handle any potential errors
*
* @param
* The type of the service client
* @param
* The type of the parent object, i.e. CloudBlobContainer for downloadAttributes etc.
* @param
* The type of the expected result
* @param client
* the service client associated with the request
* @param parentObject
* the parent object
* @param task
* the StorageRequest to execute
* @param policyFactory
* the factory used to generate a new retry policy instance
* @param opContext
* an object used to track the execution of the operation
* @return the result of the operation
* @throws StorageException
* an exception representing any error which occurred during the operation.
*/
public static RESULT_TYPE executeWithRetry(final CLIENT_TYPE client,
final PARENT_TYPE parentObject, final StorageRequest task,
final RetryPolicyFactory policyFactory, final OperationContext opContext) throws StorageException {
RetryPolicy policy = null;
if (policyFactory == null) {
policy = new RetryNoRetry();
}
else {
policy = policyFactory.createInstance(opContext);
// if the returned policy is null, set to not retry
if (policy == null) {
policy = new RetryNoRetry();
}
}
int currentRetryCount = 0;
StorageException translatedException = null;
HttpURLConnection request = null;
final long startTime = new Date().getTime();
while (true) {
try {
// 1-4: setup the request
request = setupStorageRequest(client, parentObject, task, currentRetryCount, opContext);
Logger.info(opContext, LogConstants.START_REQUEST, request.getURL(),
request.getRequestProperty(Constants.HeaderConstants.DATE));
// 5. Potentially upload data
boolean responseReceivedEventTriggered = false;
try {
if (task.getSendStream() != null) {
Logger.info(opContext, LogConstants.UPLOAD);
// Always set fixed length streaming mode when we know the length in advance.
// This sets the Content-Length of the request and allows the request payload to
// be streamed from the source. Otherwise, the HTTP layer will buffer the entire
// request and compute the Content-Length itself.
if (task.getLength() >= 0) {
request.setFixedLengthStreamingMode(task.getLength());
}
final StreamMd5AndLength descriptor = Utility.writeToOutputStream(task.getSendStream(),
request.getOutputStream(), task.getLength(), false /* rewindStream */,
false /* calculate MD5 */, opContext, task.getRequestOptions());
task.validateStreamWrite(descriptor);
Logger.info(opContext, LogConstants.UPLOADDONE);
}
Utility.logHttpRequest(request, opContext);
// 6. Process the request - Get response
RequestResult currResult = task.getResult();
currResult.setStartDate(new Date());
Logger.info(opContext, LogConstants.GET_RESPONSE);
currResult.setStatusCode(request.getResponseCode());
currResult.setStatusMessage(request.getResponseMessage());
currResult.setStopDate(new Date());
currResult.setServiceRequestID(BaseResponse.getRequestId(request));
currResult.setEtag(BaseResponse.getEtag(request));
currResult.setRequestDate(BaseResponse.getDate(request));
currResult.setContentMD5(BaseResponse.getContentMD5(request));
currResult.setErrorCode(BaseResponse.getErrorCode(request));
// 7. Fire ResponseReceived Event
responseReceivedEventTriggered = true;
ExecutionEngine.fireResponseReceivedEvent(opContext, request, task.getResult());
Logger.info(opContext, LogConstants.RESPONSE_RECEIVED, currResult.getStatusCode(),
currResult.getServiceRequestID(), currResult.getContentMD5(), currResult.getEtag(),
currResult.getRequestDate());
Utility.logHttpResponse(request, opContext);
}
finally {
Logger.info(opContext, LogConstants.ERROR_RECEIVING_RESPONSE);
if (!responseReceivedEventTriggered) {
if (task.getResult().getStartDate() == null) {
task.getResult().setStartDate(new Date());
}
ExecutionEngine.fireErrorReceivingResponseEvent(opContext, request, task.getResult());
}
}
// 8. Pre-process response to check if there was an exception. Do Response parsing (headers etc).
Logger.info(opContext, LogConstants.PRE_PROCESS);
RESULT_TYPE result = task.preProcessResponse(parentObject, client, opContext);
Logger.info(opContext, LogConstants.PRE_PROCESS_DONE);
if (!task.isNonExceptionedRetryableFailure()) {
// 9. Post-process response. Read stream from server.
Logger.info(opContext, LogConstants.POST_PROCESS);
result = task.postProcessResponse(request, parentObject, client, opContext, result);
Logger.info(opContext, LogConstants.POST_PROCESS_DONE);
// Success return result and drain the input stream.
if ((task.getResult().getStatusCode() >= 200) && (task.getResult().getStatusCode() < 300)) {
if (request != null) {
InputStream inStream = request.getInputStream();
// At this point, we already have a result / exception to return to the user.
// This is just an optimization to improve socket reuse.
try {
Utility.writeToOutputStream(inStream, null, -1, false, false, null,
task.getRequestOptions());
}
catch (final IOException ex) {
}
catch (StorageException e) {
}
finally {
inStream.close();
}
}
}
Logger.info(opContext, LogConstants.COMPLETE);
return result;
}
else {
Logger.warn(opContext, LogConstants.UNEXPECTED_RESULT_OR_EXCEPTION);
// The task may have already parsed an exception.
translatedException = task.materializeException(opContext);
task.getResult().setException(translatedException);
// throw on non retryable status codes: 501, 505, blob type mismatch
if (task.getResult().getStatusCode() == HttpURLConnection.HTTP_NOT_IMPLEMENTED
|| task.getResult().getStatusCode() == HttpURLConnection.HTTP_VERSION
|| translatedException.getErrorCode().equals(StorageErrorCodeStrings.INVALID_BLOB_TYPE)) {
throw translatedException;
}
}
}
catch (final StorageException e) {
// In case of table batch error or internal error, the exception will contain a different
// status code and message than the original HTTP response. Reset based on error values.
task.getResult().setStatusCode(e.getHttpStatusCode());
task.getResult().setStatusMessage(e.getMessage());
task.getResult().setException(e);
Logger.warn(opContext, LogConstants.RETRYABLE_EXCEPTION, e.getClass().getName(), e.getMessage());
translatedException = e;
}
catch (final Exception e) {
// Retryable, wrap
Logger.warn(opContext, LogConstants.RETRYABLE_EXCEPTION, e.getClass().getName(), e.getMessage());
translatedException = StorageException.translateException(task, e, opContext);
task.getResult().setException(translatedException);
}
finally {
opContext.setClientTimeInMs(new Date().getTime() - startTime);
// 10. Fire RequestCompleted Event
if (task.isSent()) {
ExecutionEngine.fireRequestCompletedEvent(opContext, request, task.getResult());
}
}
// Evaluate Retry Policy
Logger.info(opContext, LogConstants.RETRY_CHECK, currentRetryCount, task.getResult().getStatusCode(),
translatedException == null ? null : translatedException.getMessage());
task.setCurrentLocation(getNextLocation(task.getCurrentLocation(), task.getLocationMode()));
Logger.info(opContext, LogConstants.NEXT_LOCATION, task.getCurrentLocation(), task.getLocationMode());
RetryContext retryContext = new RetryContext(currentRetryCount++, task.getResult(),
task.getCurrentLocation(), task.getLocationMode());
RetryInfo retryInfo = policy.evaluate(retryContext, opContext);
if (retryInfo == null) {
// policy does not allow for retry
Logger.error(opContext, LogConstants.DO_NOT_RETRY_POLICY, translatedException == null ? null
: translatedException.getMessage());
throw translatedException;
}
else if (Utility.validateMaxExecutionTimeout(task.getRequestOptions().getOperationExpiryTimeInMs(),
retryInfo.getRetryInterval())) {
// maximum execution time would be exceeded by current time plus retry interval delay
TimeoutException timeoutException = new TimeoutException(SR.MAXIMUM_EXECUTION_TIMEOUT_EXCEPTION);
translatedException = new StorageException(StorageErrorCodeStrings.OPERATION_TIMED_OUT,
SR.MAXIMUM_EXECUTION_TIMEOUT_EXCEPTION, Constants.HeaderConstants.HTTP_UNUSED_306, null,
timeoutException);
task.initialize(opContext);
task.getResult().setException(translatedException);
Logger.error(opContext, LogConstants.DO_NOT_RETRY_TIMEOUT, translatedException == null ? null
: translatedException.getMessage());
throw translatedException;
}
else {
// attempt to retry
task.setCurrentLocation(retryInfo.getTargetLocation());
task.setLocationMode(retryInfo.getUpdatedLocationMode());
Logger.info(opContext, LogConstants.RETRY_INFO, task.getCurrentLocation(), task.getLocationMode());
try {
ExecutionEngine.fireRetryingEvent(opContext, task.getConnection(), task.getResult(), retryContext);
Logger.info(opContext, LogConstants.RETRY_DELAY, retryInfo.getRetryInterval());
Thread.sleep(retryInfo.getRetryInterval());
}
catch (final InterruptedException e) {
// Restore the interrupted status
Thread.currentThread().interrupt();
}
}
}
}
private static HttpURLConnection setupStorageRequest(
final CLIENT_TYPE client, final PARENT_TYPE parentObject,
final StorageRequest task, int currentRetryCount,
final OperationContext opContext) throws StorageException {
try {
// reset result flags
task.initialize(opContext);
if (Utility.validateMaxExecutionTimeout(task.getRequestOptions().getOperationExpiryTimeInMs())) {
// maximum execution time would be exceeded by current time
TimeoutException timeoutException = new TimeoutException(SR.MAXIMUM_EXECUTION_TIMEOUT_EXCEPTION);
throw new StorageException(StorageErrorCodeStrings.OPERATION_TIMED_OUT,
SR.MAXIMUM_EXECUTION_TIMEOUT_EXCEPTION, Constants.HeaderConstants.HTTP_UNUSED_306, null,
timeoutException);
}
// Run the recovery action if this is a retry. Else, initialize the location mode for the task.
// For retries, it will be initialized in retry logic.
if (currentRetryCount > 0) {
task.recoveryAction(opContext);
Logger.info(opContext, LogConstants.RETRY);
}
else {
task.applyLocationModeToRequest();
task.initializeLocation();
Logger.info(opContext, LogConstants.STARTING);
}
task.setRequestLocationMode();
// If the command only allows for a specific location, we should target
// that location no matter what the retry policy says.
task.validateLocation();
Logger.info(opContext, LogConstants.INIT_LOCATION, task.getCurrentLocation(), task.getLocationMode());
// 1. Build the request
HttpURLConnection request = task.buildRequest(client, parentObject, opContext);
// 2. Add headers
task.setHeaders(request, parentObject, opContext);
// Add any other custom headers that users have set on the opContext
if (opContext.getUserHeaders() != null) {
for (final Entry entry : opContext.getUserHeaders().entrySet()) {
request.setRequestProperty(entry.getKey(), entry.getValue());
}
}
// 3. Fire sending request event
ExecutionEngine.fireSendingRequestEvent(opContext, request, task.getResult());
task.setIsSent(true);
// 4. Sign the request
task.signRequest(request, client, opContext);
// set the connection on the task
task.setConnection(request);
return request;
}
catch (StorageException e) {
throw e;
}
catch (Exception e) {
throw new StorageException(null, e.getMessage(), Constants.HeaderConstants.HTTP_UNUSED_306, null, e);
}
}
private static StorageLocation getNextLocation(StorageLocation lastLocation, LocationMode locationMode) {
switch (locationMode) {
case PRIMARY_ONLY:
return StorageLocation.PRIMARY;
case SECONDARY_ONLY:
return StorageLocation.SECONDARY;
case PRIMARY_THEN_SECONDARY:
case SECONDARY_THEN_PRIMARY:
return (lastLocation == StorageLocation.PRIMARY) ? StorageLocation.SECONDARY : StorageLocation.PRIMARY;
default:
return StorageLocation.PRIMARY;
}
}
/**
* Fires events representing that a request will be sent.
*/
private static void fireSendingRequestEvent(OperationContext opContext, HttpURLConnection request,
RequestResult result) {
if (opContext.getSendingRequestEventHandler().hasListeners()
|| OperationContext.getGlobalSendingRequestEventHandler().hasListeners()) {
SendingRequestEvent event = new SendingRequestEvent(opContext, request, result);
opContext.getSendingRequestEventHandler().fireEvent(event);
OperationContext.getGlobalSendingRequestEventHandler().fireEvent(event);
}
}
/**
* Fires events representing that a response has been received.
*/
private static void fireResponseReceivedEvent(OperationContext opContext, HttpURLConnection request,
RequestResult result) {
if (opContext.getResponseReceivedEventHandler().hasListeners()
|| OperationContext.getGlobalResponseReceivedEventHandler().hasListeners()) {
ResponseReceivedEvent event = new ResponseReceivedEvent(opContext, request, result);
opContext.getResponseReceivedEventHandler().fireEvent(event);
OperationContext.getGlobalResponseReceivedEventHandler().fireEvent(event);
}
}
/**
* Fires events representing that an error occurred when receiving the response.
*/
private static void fireErrorReceivingResponseEvent(OperationContext opContext, HttpURLConnection request,
RequestResult result) {
if (opContext.getErrorReceivingResponseEventHandler().hasListeners()
|| OperationContext.getGlobalErrorReceivingResponseEventHandler().hasListeners()) {
ErrorReceivingResponseEvent event = new ErrorReceivingResponseEvent(opContext, request, result);
opContext.getErrorReceivingResponseEventHandler().fireEvent(event);
OperationContext.getGlobalErrorReceivingResponseEventHandler().fireEvent(event);
}
}
/**
* Fires events representing that a response received from the service is fully processed.
*/
private static void fireRequestCompletedEvent(OperationContext opContext, HttpURLConnection request,
RequestResult result) {
if (opContext.getRequestCompletedEventHandler().hasListeners()
|| OperationContext.getGlobalRequestCompletedEventHandler().hasListeners()) {
RequestCompletedEvent event = new RequestCompletedEvent(opContext, request, result);
opContext.getRequestCompletedEventHandler().fireEvent(event);
OperationContext.getGlobalRequestCompletedEventHandler().fireEvent(event);
}
}
/**
* Fires events representing that a request will be retried.
*/
private static void fireRetryingEvent(OperationContext opContext, HttpURLConnection request, RequestResult result,
RetryContext retryContext) {
if (opContext.getRetryingEventHandler().hasListeners()
|| OperationContext.getGlobalRetryingEventHandler().hasListeners()) {
RetryingEvent event = new RetryingEvent(opContext, request, result, retryContext);
opContext.getRetryingEventHandler().fireEvent(event);
OperationContext.getGlobalRetryingEventHandler().fireEvent(event);
}
}
}
