From 8c9e87d0a60cd5395c65dd354522c0865adc47b5 Mon Sep 17 00:00:00 2001 From: Matthew Holt Date: Mon, 28 Oct 2024 15:21:47 -0600 Subject: [PATCH] reverseproxy: Separate ignore_client_gone option Sponsor request is to terminate streaming connections with backend when client leaves, but wants immediate flushing. See #4922 and #4952. --- .../caddyhttp/reverseproxy/reverseproxy.go | 28 +++++++++++-------- 1 file changed, 17 insertions(+), 11 deletions(-) diff --git a/modules/caddyhttp/reverseproxy/reverseproxy.go b/modules/caddyhttp/reverseproxy/reverseproxy.go index 08be40d62..0abc07f08 100644 --- a/modules/caddyhttp/reverseproxy/reverseproxy.go +++ b/modules/caddyhttp/reverseproxy/reverseproxy.go @@ -106,13 +106,16 @@ type Handler struct { // response is recognized as a streaming response, or if its // content length is -1; for such responses, writes are flushed // to the client immediately. - // - // Normally, a request will be canceled if the client disconnects - // before the response is received from the backend. If explicitly - // set to -1, client disconnection will be ignored and the request - // will be completed to help facilitate low-latency streaming. FlushInterval caddy.Duration `json:"flush_interval,omitempty"` + // Normally, a request will be canceled if the client disconnects + // before the response is received from the backend. If enabled, + // client disconnection will be ignored and the request with the + // backend will carry on until the backend terminates it. This + // can help facilitate low-latency streaming. See #4922 and #4952. + // EXPERIMENTAL: Will likely be removed in the future. + IgnoreClientGone bool `json:"ignore_client_gone,omitempty"` + // A list of IP ranges (supports CIDR notation) from which // X-Forwarded-* header values should be trusted. By default, // no proxies are trusted, so existing values will be ignored @@ -773,12 +776,15 @@ func (h *Handler) reverseProxy(rw http.ResponseWriter, req *http.Request, origRe } req = req.WithContext(httptrace.WithClientTrace(req.Context(), trace)) - // if FlushInterval is explicitly configured to -1 (i.e. flush continuously to achieve - // low-latency streaming), don't let the transport cancel the request if the client - // disconnects: user probably wants us to finish sending the data to the upstream - // regardless, and we should expect client disconnection in low-latency streaming - // scenarios (see issue #4922) - if h.FlushInterval == -1 { + // if enabled, don't let the transport cancel the request if the client disconnects: + // user probably wants us to finish sending the data to the upstream regardless, + // and we should expect client disconnection in low-latency streaming scenarios + // (see issue #4922) + // TODO: An ideal solution, if the client disconnects before the backend is done + // receiving data from the proxy, is to wait until the baxkend is done receiving + // the data and then close the connection with the backend, rather than an explicit + // option to always leave it open... + if h.IgnoreClientGone { req = req.WithContext(ignoreClientGoneContext{req.Context()}) }