使用转发代理从客户端到服务器的 GRPC

Question

Using grpc from either nodejs or java, what are the properties or configuration necessary to get a grpc client to connect to a server through a proxy?

I have been unable to find either an example or a document explaining the settings. Do I need to do something in the code itself?

I am behind a proxy and I am not sure if the issue is that my settings are incorrect or that my proxy does not support grpc. It supports http/2 as a protocol upgrade.

My proxy settings in java are:

-Dhttp.proxyHost=xxx.xxx.xxx
-Dhttp.proxyPort=8888 
-Dhttp.nonProxyHosts="*.nowhere.nothing"
-Dhttps.proxyHost=xxx.xxx.com
-Dhttps.proxyPort=8888
-Dhttps.nonProxyHosts="*.nowhere.nothing"
-Dsocks.proxyHost=xxx.xxx.xxx
-Dsocks.proxyPort=8888
-Dsocks.nonProxyHosts="*.nowhere.nothing"

Answer 1

Since grpc-java 1.0.3 you can specify the environment variable GRPC_PROXY_EXP with a value in the form host:port . The "EXP" means experimental, as it will be removed after grpc-java observes the normal Java settings (like https.proxyHost ).

Answer 2

If you prefer to not use the global https.proxyHost , https.proxyPort properties, you could use the StubSettings of your client to specify a ChannelConfigurator . It might then look like this:

InetSocketAddress proxyAddress = new InetSocketAddress("my.proxy.local", 8080);
InstantiatingGrpcChannelProvider transportProvider = SessionsStubSettings.defaultGrpcTransportProviderBuilder()
    .setChannelConfigurator(new ApiFunction<ManagedChannelBuilder, ManagedChannelBuilder>() {
        @Override
        public ManagedChannelBuilder apply(ManagedChannelBuilder input) {
            return input.proxyDetector(new ProxyDetector() {
                @Override
                public ProxiedSocketAddress proxyFor(SocketAddress targetServerAddress) throws IOException {
                    if (!(targetServerAddress instanceof InetSocketAddress) || targetServerAddress == null) {
                        return null;
                    } 
                    return HttpConnectProxiedSocketAddress.newBuilder()
                        .setTargetAddress((InetSocketAddress) targetServerAddress)
                        .setProxyAddress(proxyAddress)
                        .build();
                    }
                });
            }
    })
    .build();

and then you could use the stubSettings bellow to create your GRPC client:

stubSettings = XYZStubSettings.newBuilder().setTransportChannelProvider(transportProvider);

Answer 3

In later releases (I think since 1.8.0+) you need:

System.setProperty("http.proxyHost", "http-ip-address-hostname");
System.setProperty("http.proxyPort", "http-port-value");    
System.setProperty("https.proxyHost", "https-ip-address-hostname");
System.setProperty("https.proxyPort", "https-port-value");