billierinaldi commented on a change in pull request #1925: URL: https://github.com/apache/hadoop/pull/1925#discussion_r594678812
########## File path: hadoop-tools/hadoop-azure/src/main/java/org/apache/hadoop/fs/azurebfs/services/SelfRenewingLease.java ########## @@ -0,0 +1,218 @@ +/** + * 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.azurebfs.services; + +import java.io.IOException; +import java.net.HttpURLConnection; +import java.util.concurrent.CancellationException; +import java.util.concurrent.TimeUnit; + +import org.apache.hadoop.thirdparty.com.google.common.util.concurrent.FutureCallback; +import org.apache.hadoop.thirdparty.com.google.common.util.concurrent.ListenableScheduledFuture; +import org.apache.hadoop.thirdparty.org.checkerframework.checker.nullness.qual.Nullable; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import org.apache.hadoop.fs.azurebfs.constants.HttpHeaderConfigurations; +import org.apache.hadoop.fs.azurebfs.contracts.exceptions.AbfsRestOperationException; +import org.apache.hadoop.fs.azurebfs.contracts.exceptions.AzureBlobFileSystemException; +import org.apache.hadoop.io.retry.RetryPolicies; +import org.apache.hadoop.io.retry.RetryPolicy; + +import static org.apache.hadoop.fs.azurebfs.constants.FileSystemConfigurations.INFINITE_LEASE_DURATION; +import static org.apache.hadoop.fs.azurebfs.services.AbfsErrors.ERR_ACQUIRING_LEASE; +import static org.apache.hadoop.fs.azurebfs.services.AbfsErrors.ERR_LEASE_FUTURE_EXISTS; +import static org.apache.hadoop.fs.azurebfs.services.AbfsErrors.ERR_NO_LEASE_THREADS; + +/** + * An Azure blob lease that automatically renews itself indefinitely by scheduling lease + * operations through the ABFS client. Use it to prevent writes to the blob by other processes + * that don't have the lease. + * + * Creating a new Lease object blocks the caller until the Azure blob lease is acquired. It will + * retry a fixed number of times before failing if there is a problem acquiring the lease. + * + * Call free() to release the Lease. If the holder process dies, the lease will time out since it + * won't be renewed. + */ +public final class SelfRenewingLease { + private static final Logger LOG = LoggerFactory.getLogger(SelfRenewingLease.class); + + static final float LEASE_RENEWAL_PERCENT_OF_DURATION = 0.67f; // Lease renewal percent of duration + + static final int LEASE_ACQUIRE_RETRY_INTERVAL = 10; // Retry interval for acquiring lease in secs + static final int LEASE_ACQUIRE_MAX_RETRIES = 7; // Number of retries for acquiring lease + + private final AbfsClient client; + private final String path; + private final int duration; + private final int renewalPeriod; + + // Lease status variables + private volatile boolean leaseFreed; + private volatile String leaseID = null; + private volatile Throwable exception = null; + private volatile ListenableScheduledFuture<AbfsRestOperation> future = null; + + public static class LeaseException extends AzureBlobFileSystemException { + public LeaseException(Throwable t) { + super(ERR_ACQUIRING_LEASE + ": " + t, t); + } + + public LeaseException(String s) { + super(s); + } + } + + public SelfRenewingLease(AbfsClient client, String path, int duration) throws AzureBlobFileSystemException { Review comment: Thanks Sneha, I didn't realize the lease renewals would be charged as write ops. It might be a poor experience for a user to have unexpected charges related to this lease configuration. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
