How to get the socket information from HttpClient request?

[pengweiqhca]

How to get the socket information(such as source ip address and target ip address) from HttpResponseMessage or related exception?

If it is not currently supported, can it be provided in the next version?

[ghost]

Tagging subscribers to this area: @dotnet/ncl
See info in area-owners.md if you want to be subscribed.

Issue Details

---

How to get the socket information(such as source ip address and target ip address) from HttpResponseMessage?

If it is not currently supported, can it be provided in the next version?

Author:	pengweiqhca
Assignees:	-
Labels:	area-System.Net, untriaged
Milestone:	-

[zxzhuty]

e.g:

        [HttpGet]
        public string Get()
        {

            var feature = Request.HttpContext.Features.Get<IHttpConnectionFeature>();
            //return feature.LocalIpAddress.ToString();
            return feature.RemoteIpAddress.ToString();

        }

Good luck.

[pengweiqhca]

Is http client request, not asp.net/asp.net core.

[geoffkizer]

Can you explain why you care about this information?

edit: To answer the original question, there's no way to get this info from HttpResponseMessage currently.

We could consider adding this in the future, but to do so we need to understand the motivation for it.

[zxzhuty]

.Net 6

using System.Net.Sockets;

SocketsHttpHandler handler = new SocketsHttpHandler();
handler.ConnectCallback = async (context, cancellationToken) =>
{
    Socket socket = new Socket(SocketType.Stream, ProtocolType.Tcp);
    socket.NoDelay = true;

    try
    {
        await socket.ConnectAsync(context.DnsEndPoint, cancellationToken).ConfigureAwait(false);
        Console.WriteLine(context.DnsEndPoint);
        Console.WriteLine(socket.RemoteEndPoint.ToString()); //IP Address 
        return new NetworkStream(socket, true);
    }
    catch
    {
        socket.Dispose();
        throw;
    }
};
using (var httpClient = new HttpClient(handler))
{
    var result = await httpClient.GetAsync("https://www.google.com");
}

[pengweiqhca]

Can you explain why you care about this information?

edit: To answer the original question, there's no way to get this info from HttpResponseMessage currently.

We could consider adding this in the future, but to do so we need to understand the motivation for it.

Some hosts hava many ip, I need to know which ip failed when accessing.

[pengweiqhca]

Re: @zxzhuty

Not only cannot connect, but also should get the infomation when status code 4XX, 5XX

[wfurt]

audit logs was big one I have seen in the past @geoffkizer. Either for regulatory reasons or for troubleshooting.

[ghost]

Tagging subscribers to this area: @dotnet/ncl
See info in area-owners.md if you want to be subscribed.

Issue Details

---

How to get the socket information(such as source ip address and target ip address) from HttpResponseMessage or related exception?

If it is not currently supported, can it be provided in the next version?

Author:	pengweiqhca
Assignees:	-
Labels:	area-System.Net, area-System.Net.Http, untriaged
Milestone:	-

[zxzhuty]

I used other methods to achieve it.There may be additional performance loss and danger.Use caution.

.NET 6 Program.cs

using System.Net.Sockets;

SocketsHttpHandler handler = new SocketsHttpHandler();
handler.ConnectCallback = async (context, cancellationToken) =>
{
    Socket socket = new Socket(SocketType.Stream, ProtocolType.Tcp);
    socket.NoDelay = true;

    try
    {
        await socket.ConnectAsync(context.DnsEndPoint, cancellationToken).ConfigureAwait(false);
        context.InitialRequestMessage.Options.TryAdd("IP", socket.RemoteEndPoint);
        return new NetworkStream(socket, true);
    }
    catch
    {
        socket.Dispose();
        throw;
    }
};


ResponseHandler responseHandler = new ResponseHandler();
responseHandler.InnerHandler = handler;


using (var httpClient = new HttpClient(responseHandler))
{
    var result = await httpClient.GetAsync("https://www.google.com");
    Console.WriteLine(result.StatusCode);
    if (result.StatusCode == System.Net.HttpStatusCode.OK)// or other
    {
        Console.WriteLine(result.RequestMessage.Options.FirstOrDefault(x => x.Key == "IP").Value.ToString());
    }
}

public class ResponseHandler : DelegatingHandler
{
    public ResponseHandler()
    {
        InnerHandler = new HttpClientHandler();
    }
    protected async override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
    {

        var response = await base.SendAsync(request, cancellationToken);
        response.RequestMessage.Options.TryAdd("IP", request.Options.Where(x => x.Key == "IP").FirstOrDefault());
        return response;
    }
}

[pengweiqhca]

👍👍👍But only the first request works.

[zxzhuty]

Can you elaborate on that? I tried a few links.it work well,The console prints the information I want

[wfurt]

As @geoffkizer mentioned, there is no good way how to associate response with given connection. The code above always works for first request since it is passed in. Then later connection can be reused for other requests unless `Connection: close' is used (or server does it). Or new connection can be created if request is still pending and the old one may or may not be used in the future.

[pengweiqhca]

Can you elaborate on that? I tried a few links.it work well,The console prints the information I want

using var httpClient = new HttpClient(responseHandler);

var result = await httpClient.GetAsync("https://www.bing.com");

Console.WriteLine(result.StatusCode);
Console.WriteLine(result.RequestMessage.Options.First(x => x.Key == "IP").Value.ToString());
result = await httpClient.GetAsync("https://www.bing.com");

Console.WriteLine(result.StatusCode);
Console.WriteLine(result.RequestMessage.Options.First(x => x.Key == "IP").Value.ToString());

Console output:

OK
[::ffff:202.89.233.101]:443
OK
[, ]

[zxzhuty]

@wfurt I guess he's right .

httpClient.DefaultRequestHeaders.Add("Connection", "close");

[karelz]

Triage:

• Complication: Socket information is not always available - we might be operating on general Stream that wraps the information.
• It would be nice to expose something, but it seems very similar to Connection Abstraction which we will likely not do.
• @scalablecory does your current work (parts of LLHTTP) help here in any way?

[samsp-msft]

@karelz - exposing the source and destination IP on the Response for logging purposes would probably make sense. If the info is not available, then return null. I am less concerned about doing that than providing the socket that people then may want to muck with.
One thing to consider is with Http/3 the IP may change mid connection.

[scalablecory]

This will be solved with LLHTTP (unpooled HTTP) APIS.

However, I've seen this requested a few times now. It seems reasonable to also look at how we could provide this data in an API, or a broader callback that gives access to the socket at one or more points in a request.

It seems very trivial for HTTP/1, but HTTP/2's multiplexing and HTTP/3 using QUIC raise some questions.

• Would your use case make sense if there are 100 concurrent requests all using the same socket?
• If not, would you only ever use HTTP/1? Some things like gRPC are starting to require HTTP/2 for full feature set.
• What are you after from the socket? A callback would be more flexible, but maybe a specific API could be made for e.g. metrics, local/remote endpoints, or configuration.

[wfurt]

While I feel StreamID would be nice, basic IP info would be sufficient for debugging with upstream firewalls/servers and it would allow to find relevant data easily with lot for concurrency.
That should be probably also sufficient for audit logs if you want to associate user with particular connection.
I know the transport may not be TCP/NetworkStream. We can either return nothing since the user was responsible for creating it. Or we could return transport stream itself. While that may expose some misuse, it would be easy and generic. And callers already may have hands on the socket - as the example above.

[wfurt]

BTW #38407 seems to dup of this.

[karelz]

Triage: It is reasonable to ask for this and we have seen occasionally customers to ask for it.
Biggest value would be in ability to process it programmatically or log it in app.

We should likely expose the transport Stream or add some callback? Prototyping would be useful.
Needs more thoughts. And should work also for https.
QUIC in HTTP/3 would be another problem.

Another idea: Expose ConnectionInfo for diagnostics.

Lifetime management will be also tricky if we link back or initialize lazily.

[mortengc]

Please prioritize this feature.

I’m working on improving the logs for my service. Basically, I would like to understand to what IP address my request was sent both in situations where the requests got a response and for cases were the request doesn’t. The destination host name is supported by a hierarchy of Azure Traffic Managers (ATM) that load balances traffic to a list (+50) of Classic Cloud Services (CCS) and I would like to be able to pinpoint issues for a specific CCS.

Since I own the down stream service I'm appending customer headers to successful responses, but this provides little help when requests are timed out or in any cases where a response is not provided.

If an ETA exists can you please provide it or maybe provide a temporary workaround here until the fix is in.
Thanks in advance.

[MihaZupan]

Here's a temporary workaround for how to do this sort of correlation reliably, limited to HTTP/1.X: https://gist.github.com/MihaZupan/8f28566fdc4b8e20491221ed84362fcf

Due to how HTTP/2 multiplexing works, the same approach doesn't work there.

[wfurt]

Would this work for parallel requests and cases when the connection is already established e.g. used from the ConnectionPool @MihaZupan ?

[MihaZupan]

Yes, but only for HTTP/1. The code is looking at which stream is seeing WriteAsync calls in the async scope of a given request.

[davidfowl]

No async locals please 😢

[karelz]

Triage: Moving to 8.0 as multiple customers run into this with very ugly workaround.

[MihaZupan]

Worth noting is that we shouldn't forget about the failure scenario where you don't even get a response message object. This likely means including information on the exception as well.

[antonfirsov]

Another aspect worth discussing: If we add new information (properties?) to HttpResponseMessage and HttpRequestException, how should we deal with them in case of handlers other than SocketsHttpHandler? If we don't fill the new properties, that might be unexpected for code that aims to be handler-agnostic or cross-platform. (Eg. uses BrowserHttpHandler on Blazor.)

[davidfowl]

Isn't that why properties is a bag? ASP.NET Core deals with this via the feature collection model. General features can be agnostic of the underlying transport, and transports can influence features that flow from connection -> request. We should do something similar here. The transport (Connect callback), needs to a bag that flows from connection to request.

[mortengc]

Please consider that IP information is also important in cases where connection was not established, but only attempted. If the information was appended to e.g. the options dictionary this would provide an opportunity to back port to previous .NET versions.

[antonfirsov]

We had several rounds of offline discussions on this topic, involving @MihaZupan, @karelz and @mortengc. Unfortunately our conclusion is that we can only provide a limited solution for this feature request.

Starting with .NET 6.0, connection pooling has been reworked so that requests and connection attempts are decoupled to improve throughput. Even though a request may initiate a new connection attempt, it might be served by a different connection that becomes available in the meanwhile. The exact logic is an implementation detail, and may change between releases. This means that - by design - there is no way to associate a remote IP endpoints with an HttpRequestMessage or HttpRequestException for failed connection attempts. Request-bound IP information is only available when a successful connection is assigned to a request.

Considering the above limitation, and the fact this is a diagnostic concern, we do not think that exposing an API would be a good idea. We should instead consider extending our telemetry with connection-level information, eg. in the way proposed in #85729:

- ConnectionEstablished(byte versionMajor, byte versionMinor)
+ ConnectionEstablished(byte versionMajor, byte versionMinor, long connectionId, string scheme, string host, int port, string? remoteEndPoint)

- ConnectionClosed(byte versionMajor, byte versionMinor)
+ ConnectionClosed(byte versionMajor, byte versionMinor, long connectionId)

- RequestHeadersStart()
+ RequestHeadersStart(long connectionId)

This extension would enable tracking connections together with their remoteEndPoint, and their association with requests thanks to the connectionId passed to the RequestHeadersStart event, making it possible to do IP diagnostics for requests with successful connections by consuming networking telemetry.

Users who would want to log IP information together outgoing HttpClient send calls, could do it by implementing an EventListener - see this gist. The solution in the gist depends on async locals, but note that it's much simpler (and thus less prone to mistakes) than the workaround suggested in #63159 (comment). Once again, this would only dispatch remote endpoint values for successful connections.

To log remote endpoints for failed connection attempts, we don't think there is a need for new telemetry extensions. Existing events from the System.Net.NameResolution and the System.Net.Sockets telemetry providers already contain enough information, when linked together with their ActivityId-s.

Users who don't want to use telemetry and/or need tighter control on their logging can override ConnectCallback and implement manual DNS resolution and IP logging there. Note that this should be connection-level logging where connection attempts should not be associated with requests, even though it's technically possible to do so by using SocketsHttpConnectionContext.InitialRequestMessage. That property is not reliable, and will be obsoleted in .NET 8.0, see #66989.

[antonfirsov]

Triage:

• We agreed to improve our support to this scenario by implementing How to get the socket information from HttpClient request? #63159 (comment) / Adding more information and events to System.Net.Http telemetry #85729
• Eventually, an API-based solution would be nice to make consumption simpler (related: How to identify HttpClient connect timeout errors? #78070)

[antonfirsov]

@dotnet/ncl in the discussion resulting to the proposal in #63159 (comment), for some reason we assumed connections already store a long id, which is used by our internal diagnostics. This seems to be wrong after looking at the code or example Private.InternalDiagnostics trace outputs.

Since we generally prefer "pay for play" and likely don't want to penalize the majority of the use-cases which have telemetry events turned off, I recommend to proceed with the first idea from #85729 emitting data on RequestHeadersStart directly.

-void RequestHeadersStart();
+void RequestHeadersStart(string scheme, string host, int port, string pathAndQuery, byte versionMajor, byte versionMinor, string? remoteEndPoint);

[MihaZupan]

pay for play

If we think that the added diagnostic data is useful, I think it's acceptable to pay the 8 bytes+interlocked per connection (or are there other costs involved?).

[antonfirsov]

or are there other costs involved

No, that's all. TBH the second option seems to be much cleaner from telemetry perspective and I like it better if we don't need to stick to the "pay for play" rule strictly.