reverseproxy: Revert #4952 - don't ignore context cancellation in stream mode

i.e. Revert commit f5dce84a7028d1b116db7fead27ff8b2506baf78 Two years ago, the patch in #4952 was a seemingly necessary way to fix an issue (sort of an edge case), but it broke other more common use cases (see #6666). Now, as of #6669, it seems like the original issue can no longer be replicated, so we are reverting that patch, because it was incorrect anyway. If it turns out the original issue returns, a more proper patch may be in #6669 (even if used as a baseline for a future fix). A potential future fix could be an opt-in setting.

Matthew Holt committed Nov 12, 2024 at 13:43 UTC 238f1108e6600049d9041abc88db24526ee4f882

1 file changed -14

modules/caddyhttp/reverseproxy/reverseproxy.go

-14

@@ -108,11 +108,6 @@ type Handler struct {

108 // response is recognized as a streaming response, or if its

109 // content length is -1; for such responses, writes are flushed

110 // to the client immediately.

111 - //

112 - // Normally, a request will be canceled if the client disconnects

113 - // before the response is received from the backend. If explicitly

114 - // set to -1, client disconnection will be ignored and the request

115 - // will be completed to help facilitate low-latency streaming.

111 FlushInterval caddy.Duration `json:"flush_interval,omitempty"`

112

113 // A list of IP ranges (supports CIDR notation) from which

@@ -833,15 +828,6 @@ func (h *Handler) reverseProxy(rw http.ResponseWriter, req *http.Request, origRe

828 }

829 req = req.WithContext(httptrace.WithClientTrace(req.Context(), trace))

830

836 - // if FlushInterval is explicitly configured to -1 (i.e. flush continuously to achieve

837 - // low-latency streaming), don't let the transport cancel the request if the client

838 - // disconnects: user probably wants us to finish sending the data to the upstream

839 - // regardless, and we should expect client disconnection in low-latency streaming

840 - // scenarios (see issue #4922)

841 - if h.FlushInterval == -1 {

842 - req = req.WithContext(context.WithoutCancel(req.Context()))

843 - }

844 -

831 // do the round-trip

832 start := time.Now()

833 res, err := h.Transport.RoundTrip(req)