io.grpc.alts.HandshakerServiceChannel.java Source code

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Here is the source code for io.grpc.alts.HandshakerServiceChannel.java

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/*
 * Copyright 2018 The gRPC Authors
 *
 * 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 io.grpc.alts;

import com.google.common.base.Preconditions;
import io.grpc.ManagedChannel;
import io.grpc.netty.NettyChannelBuilder;
import io.netty.channel.nio.NioEventLoopGroup;
import io.netty.util.concurrent.DefaultThreadFactory;
import java.util.concurrent.ThreadFactory;

/**
 * Class for creating a single shared grpc channel to the ALTS Handshaker Service. The channel to
 * the handshaker service is local and is over plaintext. Each application will have at most one
 * connection to the handshaker service.
 *
 * <p>TODO: Release the channel if it is not used.
 */
final class HandshakerServiceChannel {
    // Default handshaker service address.
    private static String handshakerAddress = "metadata.google.internal:8080";
    // Shared channel to ALTS handshaker service.
    private static ManagedChannel channel = null;

    // Construct me not!
    private HandshakerServiceChannel() {
    }

    // Sets handshaker service address for testing and creates the channel to the handshaker service.
    public static synchronized void setHandshakerAddressForTesting(String handshakerAddress) {
        Preconditions.checkState(
                channel == null || HandshakerServiceChannel.handshakerAddress.equals(handshakerAddress),
                "HandshakerServiceChannel already created with a different handshakerAddress");
        HandshakerServiceChannel.handshakerAddress = handshakerAddress;
        if (channel == null) {
            channel = createChannel();
        }
    }

    /** Create a new channel to ALTS handshaker service, if it has not been created yet. */
    private static ManagedChannel createChannel() {
        /* Use its own event loop thread pool to avoid blocking. */
        ThreadFactory clientThreadFactory = new DefaultThreadFactory("handshaker pool", true);
        ManagedChannel channel = NettyChannelBuilder.forTarget(handshakerAddress).directExecutor()
                .eventLoopGroup(new NioEventLoopGroup(1, clientThreadFactory)).usePlaintext().build();
        return channel;
    }

    public static synchronized ManagedChannel get() {
        if (channel == null) {
            channel = createChannel();
        }
        return channel;
    }
}