Docker response 407 is not handled correctly resulting in no error message

[philwebb]

HttpClientTransport has the following code:

	private Response execute(HttpUriRequest request) {
		try {
			beforeExecute(request);
			ClassicHttpResponse response = this.client.executeOpen(this.host, request, null);
			int statusCode = response.getCode();
			if (statusCode >= 400 && statusCode <= 500) {
				byte[] content = readContent(response);
				response.close();
				Errors errors = (statusCode != 500) ? deserializeErrors(content) : null;
				Message message = deserializeMessage(content);
				throw new DockerEngineException(this.host.toHostString(), request.getUri(), statusCode,
						response.getReasonPhrase(), errors, message);
			}
			return new HttpClientResponse(response);
		}
		catch (IOException | URISyntaxException ex) {
			throw new DockerConnectionException(this.host.toHostString(), ex);
		}
	}

But it appears that Docker returns 407 response with a plain text message when Enforced Sign-In is required. It would be helpful if we could surface that error.

[Tejas-Teju]

Can I work on this @philwebb?

We can fall back to plain text if deserialization fails.

[cvsnehankita]

Hi Team,

I can see that deserialization is already implemented here for status code between 500 and 600,
Message message = deserializeMessage(content);

One approach I would like to suggest is adding an if case for status code 407 to throw a custom ProxyAuthenticationException. please try implementing below,

private Response execute(HttpUriRequest request) {
try {
beforeExecute(request);
ClassicHttpResponse response = this.client.executeOpen(this.host, request, null);
int statusCode = response.getCode();
if (statusCode >= 400 && statusCode <= 500) {
byte[] content = readContent(response);

                 // handle 407 Proxy Authentication Required exception
                     if (statusCode == 407) {
                            response.close();
                            throw new ProxyAuthenticationException(
                                "Proxy authentication required for host: " + this.host.toHostString() + ", URI: " + request.getUri());
                       }
			response.close();
			Errors errors = (statusCode != 500) ? deserializeErrors(content) : null;
			Message message = deserializeMessage(content);
			throw new DockerEngineException(this.host.toHostString(), request.getUri(), statusCode,
					response.getReasonPhrase(), errors, message);
		}
		return new HttpClientResponse(response);
	}
	catch (IOException | URISyntaxException ex) {
		throw new DockerConnectionException(this.host.toHostString(), ex);
	}
}

Custom exception we can implement as below
public class ProxyAuthenticationException extends RuntimeException {
public ProxyAuthenticationException(String message) {
super(message); }
}

[philwebb]

Closing in favor of PR #47180. Thanks @siva-sai-udaygiri!