com.google.cloud.bigtable.grpc.async.RetryingRpcFutureFallback.java Source code

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Here is the source code for com.google.cloud.bigtable.grpc.async.RetryingRpcFutureFallback.java

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/*
 * Copyright 2015 Google Inc. All Rights Reserved.
 *
 * 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.google.cloud.bigtable.grpc.async;

import io.grpc.Status;
import io.grpc.StatusRuntimeException;

import java.io.IOException;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.google.api.client.util.BackOff;
import com.google.cloud.bigtable.config.RetryOptions;
import com.google.cloud.bigtable.grpc.scanner.ScanRetriesExhaustedException;
import com.google.common.annotations.VisibleForTesting;
import com.google.common.util.concurrent.FutureFallback;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.ListenableFuture;

/**
 * A {@link FutureFallback} that retries a {@link RetryableRpc} request.
 */
public class RetryingRpcFutureFallback<RequestT, ResponseT> implements FutureFallback<ResponseT> {

    public static <RequestT, ResponseT> RetryingRpcFutureFallback<RequestT, ResponseT> create(
            RetryOptions retryOptions, RequestT request, RetryableRpc<RequestT, ResponseT> retryableRpc) {
        return new RetryingRpcFutureFallback<RequestT, ResponseT>(retryOptions, request, retryableRpc);
    }

    protected final Log LOG = LogFactory.getLog(RetryingRpcFutureFallback.class);

    private final RequestT request;

    @VisibleForTesting
    BackOff currentBackoff;
    @VisibleForTesting
    Sleeper sleeper = Sleeper.DEFAULT;

    private final RetryableRpc<RequestT, ResponseT> retryableRpc;
    private final RetryOptions retryOptions;

    private RetryingRpcFutureFallback(RetryOptions retryOptions, RequestT request,
            RetryableRpc<RequestT, ResponseT> retryableRpc) {
        this.retryOptions = retryOptions;
        this.request = request;
        this.retryableRpc = retryableRpc;
    }

    @Override
    public ListenableFuture<ResponseT> create(Throwable t) throws Exception {
        if (t instanceof StatusRuntimeException) {
            StatusRuntimeException statusException = (StatusRuntimeException) t;
            Status.Code code = statusException.getStatus().getCode();
            if (retryOptions.isRetryableRead(code)) {
                return backOffAndRetry(t);
            }
        }
        return Futures.immediateFailedFuture(t);
    }

    private ListenableFuture<ResponseT> backOffAndRetry(Throwable cause)
            throws IOException, ScanRetriesExhaustedException {
        if (this.currentBackoff == null) {
            this.currentBackoff = retryOptions.createBackoff();
        }
        long nextBackOff = currentBackoff.nextBackOffMillis();
        if (nextBackOff == BackOff.STOP) {
            throw new ScanRetriesExhaustedException("Exhausted streaming retries.", cause);
        }

        sleep(nextBackOff);
        return retryableRpc.call(request);
    }

    private void sleep(long millis) throws IOException {
        try {
            sleeper.sleep(millis);
        } catch (InterruptedException e) {
            Thread.currentThread().interrupt();
            throw new IOException("Interrupted while sleeping for resume", e);
        }
    }
}