add configuration option for Proxy Protocol

Dropwizard currently provides a configuration option to read X-Forwarded-* headers, useForwardedHeaders, but provides no similar configuration option to read HAProxy PROXY protocol data frames, such as those able to be sent through by AWS ELBs. The NGINX blog has a write-up about this as well.

In vanilla Jetty, this is accomplished using the ProxyConnectionFactory, as described in Jetty’s docs on configuring Connectors.

Dropwizard should include a configuration option to support reading the PROXY protocol.

[ssesha]

One way around this currently is to create and register another command which is a clone of the Server Command. I just changed the run method to add the ProxyConnectionFactory like so:

protected void run(Environment environment, Namespace namespace, T configuration) throws Exception {
final Server server = configuration.getServerFactory().build(environment);
try {
server.addLifeCycleListener(new LifeCycleListener());
cleanupAsynchronously();

  //Enable proxy protocol parsing for all connectors
  for (Connector connector : server.getConnectors()) {
    if (connector instanceof ServerConnector) {
      ServerConnector serverConnector = (ServerConnector) connector;
      LOGGER.info("proxy protocol parsing enabled on {} port {}", serverConnector.getName() , serverConnector.getLocalPort());
      serverConnector.addFirstConnectionFactory(new ProxyConnectionFactory());
    }
  }

  server.start();
} catch (Exception e) {
  LOGGER.error("Unable to start server, shutting down", e);
  try {
    server.stop();
  } catch (Exception e1) {
    LOGGER.warn("Failure during stop server", e1);
  }
  try {
    cleanup();
  } catch (Exception e2) {
    LOGGER.warn("Failure during cleanup", e2);
  }
  throw e;
}
}

and registered this as a separate command in the initialize phase of my Application

 @Override
  public void initialize (Bootstrap<ProxyConfiguration> configurationBootstrap) {
    configurationBootstrap.addCommand(new ProxyServerCommand<>(this));
  }

[tyagiakhilesh]

I tried the suggested solution but it doesn’t work! If I do as stated above, then not sure, exactly at what point does this break, but with my haproxy setup, I see

Bad Message 400

reason: Illegal character 0x0

I tested this with pure jetty. The above error happens when server side is not able to handle proxy protocol header.