forked from grpc/grpc-java
/
GrpclbNameResolverProvider.java
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/
GrpclbNameResolverProvider.java
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/*
* Copyright 2019 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.grpclb;
import io.grpc.Internal;
import io.grpc.internal.BaseDnsNameResolverProvider;
/**
* A provider for {@code io.grpc.internal.DnsNameResolver} for gRPC lb.
*
* <p>It resolves a target URI whose scheme is {@code "dns"}. The (optional) authority of the target
* URI is reserved for the address of alternative DNS server (not implemented yet). The path of the
* target URI, excluding the leading slash {@code '/'}, is treated as the host name and the optional
* port to be resolved by DNS. Example target URIs:
*
* <ul>
* <li>{@code "dns:///foo.googleapis.com:8080"} (using default DNS)</li>
* <li>{@code "dns://8.8.8.8/foo.googleapis.com:8080"} (using alternative DNS (not implemented
* yet))</li>
* <li>{@code "dns:///foo.googleapis.com"} (without port)</li>
* </ul>
*
* <p>Note: the main difference between {@code io.grpc.DnsNameResolver} is service record is enabled
* by default.
*/
@Internal
public class GrpclbNameResolverProvider extends BaseDnsNameResolverProvider {
@Override
protected boolean isSrvEnabled() {
return Boolean.parseBoolean(System.getProperty(ENABLE_GRPCLB_PROPERTY_NAME, "true"));
}
@Override
protected int priority() {
// Must be higher than DnsNameResolverProvider#priority.
return 6;
}
}