nl.topicus.jdbc.shaded.io.grpc.internal.ProxyDetector Maven / Gradle / Ivy

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/*
 * Copyright 2017 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 nl.topicus.jdbc.shaded.io.grpc.internal;

import nl.topicus.jdbc.shaded.io.grpc.Attributes;
import java.io.IOException;
import java.net.SocketAddress;
import nl.topicus.jdbc.shaded.javax.annotation.Nullable;

/**
 * A utility class to detect which proxy, if any, should be used for a given
 * {@link java.net.SocketAddress}. This class performs network requests to resolve address names,
 * and should only be used in places that are expected to do IO such as the
 * {@link nl.topicus.jdbc.shaded.io.grpc.NameResolver}.
 */
public interface ProxyDetector {
  Attributes.Key PROXY_PARAMS_KEY = Attributes.Key.create("proxy-params-key");
  /**
   * Given a target address, returns which proxy address should be used. If no proxy should be
   * used, then return value will be null. The address of the {@link ProxyParameters} is always
   * resolved. This throws if the proxy address cannot be resolved.
   */
  @Nullable
  ProxyParameters proxyFor(SocketAddress targetServerAddress) throws IOException;
}