Flight-SQL JDBC driver ignores JVM proxy settings

Describe the enhancement requested

Hi, I was making some tests for checking the support of proxies with the Flight-SQL JDBC driver.

GRPC supports the JVM properties for indicating the default http proxy to use. Nevertheless, I tested with Flight-SQL JDBC driver without luck. The driver is ignoring them.
I mean these ones:
-Dhttps.proxyHost=<host> -Dhttps.proxyPort=<port>

Checking the reason, I arrived to these lines where the Netty channel is opened:

arrow-java/flight/flight-core/src/main/java/org/apache/arrow/flight/FlightClient.java

Lines 854 to 862 in bd2173c

    
             { 
        
               builder = NettyChannelBuilder.forAddress(location.toSocketAddress()); 
        
               break; 
        
             } 
        
           case LocationSchemes.GRPC_DOMAIN_SOCKET: 
        
             { 
        
               // The implementation is platform-specific, so we have to find the classes at runtime 
        
               builder = NettyChannelBuilder.forAddress(location.toSocketAddress()); 
        
               try {

Using method io.grpc.netty.NettyChannelBuilder#forAddress(java.net.SocketAddress) makes GRPC to create the channel using a direct connection to the host:port specified at connection uri, ignoring the proxy.
This happens on this code from ManagedChannelImplBuilder

  public ManagedChannelImplBuilder(SocketAddress directServerAddress, String authority,
      @Nullable ChannelCredentials channelCreds, @Nullable CallCredentials callCreds,
      ClientTransportFactoryBuilder clientTransportFactoryBuilder,
      @Nullable ChannelBuilderDefaultPortProvider channelBuilderDefaultPortProvider) {
    this.target = makeTargetStringForDirectAddress(directServerAddress);
    this.channelCredentials = channelCreds;
    this.callCredentials = callCreds;

I am not sure if there is a special reason for not opening the connection with the host and port values, instead of the java.net.SocketAddress:

builder = NettyChannelBuilder.forAddress(
                    location.getUri().getHost(), location.getUri().getPort());

But opening the channel in the previous way makes GRPC to follow the specified proxy at JVM properties.
-Dhttps.proxyHost=<host> -Dhttps.proxyPort=<port>

Could this be a valid enhancement request?

General comment: as JDBC driver is shading and relocating the dependency (netty and gRPC especially), the properties name can be different (org.apache.arrow.io.grpc... instead of io.grpc... for instance).
Specifically for the HTTP proxy, I think a different "issue" in the way we create the gRPC/Netty channel. I will fix that.

Hi, I saw that also and I though the same.

Nevertheless, I did the test of modifying how the channel is created with the suggested code, generated a driver with the change and validated the proxy works.

builder = NettyChannelBuilder.forAddress(
                    location.getUri().getHost(), location.getUri().getPort());

So, maybe only with this change is enough.

Actually, I don't think it's a bug because:

location.toSocketAddress is actually using the URI schema.
If the schema is GRPC (e.g. grpc), GRPC_TLS (e.g. grpc+tls), GRPC_INSECURE (e.g. grpc+tcp), then uri host and port are used (and so the HTTP proxy properties can be used)
If the schema is GRPC_DOMAIN_SOCKET (e.g. grpc+unix), we are not using TCP but io.netty.channel.unix.DomainSocketAddress so only the URI path is considered (not host and port)

What's the JDBC URL used ?

Hi, I used the following for the test.
jdbc:arrow-flight-sql://localhost:3128?&useEncryption=0

I agree that proxy should apply to case 2, when the connection use http. I did not test case 3, but I think it should not be a reason for breaking case 2 ignoring JVM http proxy properties.

@scruz-denodo

@scruz-denodo thanks. I suspect either URL parsing issue or env. Let me write a quick test case to try to reproduce.

hi folks, was there any progress on proxy support for the Arrow Flight SQL JDBC Driver?

@nicornk

@nicornk Hello, I will look into this one in the coming days.

@nicornk

@nicornk I checked out the relevant part of this codebase. There was a refactor that moved the NettyChannelBuilder call to NettyClientBuilder, see https://github.com/apache/arrow-java/pull/660/changes, but the lines weren't changed.

I also confirmed that grpc-java itself recommends against using the current API for HTTP/TCP sockets, see https://github.com/grpc/grpc-java/blob/73abb48547df4cbaadddfa5bd6a82ef387fac800/netty/src/main/java/io/grpc/netty/NettyChannelBuilder.java#L125 This is not a URL parsing error, it's an incorrect usage of the gRPC NettyChannelBuilder.

I'm working on a PR to fix this. The fix itself is trivial: I'm writing unit tests for it, which is a bit more involved.

@jbonofre you're the current assignee. Is it ok if I take this one?

apacheGH-577: Use JVM proxy settings in Netty client (apache#1027)

@nicornk

@nicornk the next release should have support for proxies!

@ennuite

thank you for your efforts @ennuite !!

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Flight-SQL JDBC driver ignores JVM proxy settings #577

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	{
	builder = NettyChannelBuilder.forAddress(location.toSocketAddress());
	break;
	}
	case LocationSchemes.GRPC_DOMAIN_SOCKET:
	{
	// The implementation is platform-specific, so we have to find the classes at runtime
	builder = NettyChannelBuilder.forAddress(location.toSocketAddress());
	try {

Flight-SQL JDBC driver ignores JVM proxy settings #577

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jbonofre commented on Feb 13, 2025

scruz-denodo commented on Feb 13, 2025

jbonofre commented on Feb 13, 2025

scruz-denodo commented on Feb 13, 2025

jbonofre commented on Feb 25, 2025

nicornk commented on Jan 28, 2026

ennuite commented on Feb 6, 2026

ennuite commented on Feb 10, 2026

ennuite commented on Aug 31, 2026

nicornk commented on Aug 31, 2026

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