org.apache.hadoop.fs.azure.SendRequestIntercept.java Source code

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Here is the source code for org.apache.hadoop.fs.azure.SendRequestIntercept.java

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/**
 * 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.azure;

import java.net.HttpURLConnection;
import java.security.InvalidKeyException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;
import org.apache.hadoop.classification.InterfaceAudience;

import com.microsoft.azure.storage.Constants.HeaderConstants;
import com.microsoft.azure.storage.core.StorageCredentialsHelper;
import com.microsoft.azure.storage.OperationContext;
import com.microsoft.azure.storage.SendingRequestEvent;
import com.microsoft.azure.storage.StorageCredentials;
import com.microsoft.azure.storage.StorageEvent;
import com.microsoft.azure.storage.StorageException;

/**
 * Manages the lifetime of binding on the operation contexts to intercept send
 * request events to Azure storage.
 */
@InterfaceAudience.Private
public final class SendRequestIntercept extends StorageEvent<SendingRequestEvent> {

    public static final Log LOG = LogFactory.getLog(SendRequestIntercept.class);

    private static final String ALLOW_ALL_REQUEST_PRECONDITIONS = "*";
    private final StorageCredentials storageCreds;
    private final boolean allowConcurrentOOBIo;
    private final OperationContext opContext;

    /**
     * Getter returning the storage account credentials.
     * 
     * @return storageCreds - account storage credentials.
     */
    private StorageCredentials getCredentials() {
        return storageCreds;
    }

    /**
     * Query if out-of-band I/Os are allowed.
     * 
     * return allowConcurrentOOBIo - true if OOB I/O is allowed, and false
     * otherwise.
     */
    private boolean isOutOfBandIoAllowed() {
        return allowConcurrentOOBIo;
    }

    /**
     * Getter returning the operation context.
     * 
     * @return storageCreds - account storage credentials.
     */
    private OperationContext getOperationContext() {
        return opContext;
    }

    /**
     * Constructor for SendRequestThrottle.
     * 
     * @param storageCreds
     *          - storage account credentials for signing packets.
     * 
     */
    private SendRequestIntercept(StorageCredentials storageCreds, boolean allowConcurrentOOBIo,
            OperationContext opContext) {
        // Capture the send delay callback interface.
        this.storageCreds = storageCreds;
        this.allowConcurrentOOBIo = allowConcurrentOOBIo;
        this.opContext = opContext;
    }

    /**
     * Binds a new lister to the operation context so the WASB file system can
     * appropriately intercept sends. By allowing concurrent OOB I/Os, we bypass
     * the blob immutability check when reading streams.
     * 
     * @param opContext
     *          The operation context to bind to listener.
     * 
     * @param allowConcurrentOOBIo
     *          True if reads are allowed with concurrent OOB writes.
     */
    public static void bind(StorageCredentials storageCreds, OperationContext opContext,
            boolean allowConcurrentOOBIo) {
        SendRequestIntercept sendListener = new SendRequestIntercept(storageCreds, allowConcurrentOOBIo, opContext);
        opContext.getSendingRequestEventHandler().addListener(sendListener);
    }

    /**
     * Handler which processes the sending request event from Azure SDK. The
     * handler simply sets reset the conditional header to make all read requests
     * unconditional if reads with concurrent OOB writes are allowed.
     * 
     * @param sendEvent
     *          - send event context from Windows Azure SDK.
     */
    @Override
    public void eventOccurred(SendingRequestEvent sendEvent) {

        if (!(sendEvent.getConnectionObject() instanceof HttpURLConnection)) {
            // Pass if there is no HTTP connection associated with this send
            // request.
            return;
        }

        // Capture the HTTP URL connection object and get size of the payload for
        // the request.
        HttpURLConnection urlConnection = (HttpURLConnection) sendEvent.getConnectionObject();

        // Determine whether this is a download request by checking that the request
        // method
        // is a "GET" operation.
        if (urlConnection.getRequestMethod().equalsIgnoreCase("GET") && isOutOfBandIoAllowed()) {
            // If concurrent reads on OOB writes are allowed, reset the if-match
            // condition on the conditional header.
            urlConnection.setRequestProperty(HeaderConstants.IF_MATCH, ALLOW_ALL_REQUEST_PRECONDITIONS);

            // In the Java AzureSDK the packet is signed before firing the
            // SendRequest. Setting
            // the conditional packet header property changes the contents of the
            // packet, therefore the packet has to be re-signed.
            try {
                // Sign the request. GET's have no payload so the content length is
                // zero.
                StorageCredentialsHelper.signBlobAndQueueRequest(getCredentials(), urlConnection, -1L,
                        getOperationContext());
            } catch (InvalidKeyException e) {
                // Log invalid key exception to track signing error before the send
                // fails.
                String errString = String.format(
                        "Received invalid key exception when attempting sign packet." + " Cause: %s",
                        e.getCause().toString());
                LOG.error(errString);
            } catch (StorageException e) {
                // Log storage exception to track signing error before the call fails.
                String errString = String.format(
                        "Received storage exception when attempting to sign packet." + " Cause: %s",
                        e.getCause().toString());
                LOG.error(errString);
            }
        }
    }
}