Proxy settings via system properties not working with Spring WebClient

[VsKrishna87]

My following WebClient is working fine with internet connection but not through our proxy connection.

WebClient webClient = WebClient.builder()
        .baseUrl("https://targetsite.com")
        .build();

webClient.post()
    .uri("/service/serviceName")
    .body(BodyInserters.fromObject(reqData))
    .retrieve()
    .bodyToMono(WebServiceResponse.class)

Event though, the same client is working through proxy, if I set it as mentioned below,

HttpClient httpClient = HttpClient.create()
            .tcpConfiguration(tcpClient -> tcpClient
                .proxy(proxy -> proxy
                    .type(ProxyProvider.Proxy.HTTP)
                    .host("ourproxy.com")
                    .port(8080)));

ReactorClientHttpConnector connector = new ReactorClientHttpConnector(httpClient);

WebClient webClient = WebClient.builder()
        .clientConnector(connector)
        .baseUrl("https://targetsite.com")
        .build();

webClient.post()
    .uri("/service/serviceName")
    .body(BodyInserters.fromObject(reqData))
    .retrieve()
    .bodyToMono(WebServiceResponse.class)

But if I set the same Proxy details either using System.setProperty("http.proxyHost","ourproxy.com"); System.setProperty("http.proxyPort","8080"); or JVM run-time arguments -Dhttp.proxyHost=ourproxy.com -Dhttp.proxyPort=8080

WebClient webClient = WebClient.builder()
        .baseUrl("https://targetsite.com")
        .build();

System.setProperty("http.proxyHost", "ourproxy.com");
System.setProperty("http.proxyPort", "8080");

webClient.post()
    .uri("/service/serviceName")
    .body(BodyInserters.fromObject(reqData))
    .retrieve()
    .bodyToMono(WebServiceResponse.class)

The calls are getting failed with UnknownHostException like,

[04/11/2019 12:32:43.031 IST] DEBUG [reactor-http-epoll-3] [PooledConnectionProvider:254] - Creating new client pool [http] for targetsite.com:443
[04/11/2019 12:32:43.033 IST] DEBUG [reactor-http-epoll-3] [PooledConnectionProvider:254] - [id: 0xe4a0dc15] Created new pooled channel, now 0 active connections and 1 inactive connections
[04/11/2019 12:32:43.045 IST] DEBUG [reactor-http-epoll-3] [SslProvider:254] - [id: 0xe4a0dc15] SSL enabled using engine SSLEngineImpl and SNI targetsite.com:443
[04/11/2019 12:32:43.046 IST] DEBUG [reactor-http-epoll-3] [BootstrapHandlers:254] - [id: 0xe4a0dc15] Initialized pipeline DefaultChannelPipeline{(reactor.left.sslHandler = io.netty.handler.ssl.SslHandler), (reactor.left.sslReader = reactor.netty.tcp.SslProvider$SslReadHandler), (BootstrapHandlers$BootstrapInitializerHandler#0 = reactor.netty.channel.BootstrapHandlers$BootstrapInitializerHandler), (SimpleChannelPool$1#0 = io.netty.channel.pool.SimpleChannelPool$1), (reactor.left.httpCodec = io.netty.handler.codec.http.HttpClientCodec), (reactor.left.decompressor = io.netty.handler.codec.http.HttpContentDecompressor), (reactor.right.reactiveBridge = reactor.netty.channel.ChannelOperationsHandler)}
[04/11/2019 12:32:43.165 IST] ERROR [reactor-http-epoll-2] [AbstractErrorWebExceptionHandler:117] - [13ebf1eb] 500 Server Error for HTTP POST "/service/serviceName"
java.net.UnknownHostException: targetsite.com: Name or service not known

Please help, why my code is not functioning even I set the proxy details via JVM run-time arguments or system properties.

Actually I want to avoid code level proxy setting. So please guide me to correct my code or approach, so that I can use JVM run-time argument option.

[violetagg]

Only this is supported (system properties are not supported)

HttpClient httpClient = HttpClient.create()
            .tcpConfiguration(tcpClient -> tcpClient
                .proxy(proxy -> proxy
                    .type(ProxyProvider.Proxy.HTTP)
                    .host("ourproxy.com")
                    .port(8080)));

You can easily add/remove proxy configuration using the system properties in your code.

[nhomble]

@violetagg just curious, do we ever see the system properties to be pulled in by reactor-netty or do you expect frameworks like spring's webclientbuilder to expose this?

[rstoyanchev]

@nhomble I would say no. It's not customary to check System properties in the Spring Framework. Typically external properties from different sources (environment, properties file, etc) are injected into classes that can then configure things accordingly.

[nhomble]

I totally agree @rstoyanchev the properties wouldn't come directly from system properties. I was thinking reactor-netty could consider using the system properties directly but integration with spring should rely on configuration properties.

I have this working in my project with the config prop approach, but I wanted to make sure I am not duplicating any enhancements either reactor or spring would consider taking in.

[violetagg]

@nhomble I prefer to have only an explicit configuration using the API instead of system properties to avoid mixture of priorities .... or should it be a choice between those two configurations or a merge of those two?
2. Also let say that we have more than one client in one JVM, then should these system properties apply to all clients or only to some of them ...

[nhomble]

Great points @violetagg. For (1) I think the client builder could support both styles and to avoid the merging/ambiguity problem the builder could either take the config as-is inTcpConfiguration with .proxy(Consumer<..>) or explicitly .proxyWithSystemProperties() for lack of a better name.

For (2), I think we can continue to be flexible by not assuming system properties are a source of configuration.

My current application just provides a proxy consumer that loads the env vars manually which I figure would belong in the library. I also imagine this would help teams like mine migrate easier 😄

[violetagg]

@nhomble

explicitly .proxyWithSystemProperties() for lack of a better name.

I like the idea and will reopen the issue. So if somebody wants can provide a PR.