[release/6.0] Respect the Keep-Alive response header on HTTP/1.0#73245
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* Respect the Keep-Alive response header on HTTP/1.0 * Remove TimeoutOffset * Update Trace message * Update tests * Adjust test timeouts
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Tagging subscribers to this area: @dotnet/ncl |
ghost
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This PR has been pre-approved for 6.0.9 by Tactics today, pending final agreement with @stephentoub. |
karelz
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Update: We have reached consensus over email with @stephentoub and decided to take this change into 7.0 and 6.0.x servicing. Removing the |
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Tactics approved.
Correct milestone applied.
No CI failures.
No OOB package authoring needed (System.Net.Http.csproj does not have <IsPackable>).
Signed off by area owner.
Ready to merge! 
3 participants
Backport of #73020 and #73585
Fixes #72958
Customer Impact
There is an inherent race in HTTP/1.x between the server closing an idle connection and the client trying to send a request at the same time (#60644). To mitigate this, the server may respond with a
Keep-Alive: timeout=60header that informs the client of how long it can reuse an idle connection for.This change makes
SocketsHttpHandlerlook for this header and use it to limit the idle timeout of a connection.As a result, we avoid the race condition and fewer requests fail with a "Connection reset by peer" error.
Testing
Targeted test cases have been added and the patch was validated by an internal party in production.
Risk
There is a tradeoff between mitigating the race condition and how long we consider an idle connection usable for.
There is a risk that the user may see more connections being established if they make requests on an interval that falls within a 1-second offset of the server Keep-Alive timeout.
For example, if the server responds with a timeout of 5 seconds and the user has a script pinging the server every 4.5 seconds, every request would create a new connection instead of reusing the existing one.
Users facing such an issue can increase the interval at which they make requests or if possible increase the timeout on the server.