dnsforward: build new server state before stopping the old one - #8589
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ChenYun10 wants to merge 1 commit into
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dnsforward: build new server state before stopping the old one#8589ChenYun10 wants to merge 1 commit into
ChenYun10 wants to merge 1 commit into
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Reconfigure previously stopped the running proxy first, then slept for 100 ms, and only then prepared the new state. This kept the listeners down for the whole (potentially slow) preparation — including upstream loading and bootstrap resolution — and made clients get "connection refused" during every settings change. Build the new state before tearing the old one down, and remove the blind 100 ms sleep. The old proxy and its resources are shut down explicitly after the new state is prepared, shrinking the actual downtime window to just the final swap and start. Signed-off-by: Chen Yun <ChenYun10@users.noreply.github.com>
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Problem
Server.Reconfigurecurrently stops the running proxy first, then does a blindtime.Sleep(100 * time.Millisecond), and only then prepares the new state (loading upstreams, bootstrapping, building the filtering proxy). During this whole window the listeners are down and clients get "connection refused" on every settings change.Fix
Build the new state before tearing the old one down, and remove the 100 ms sleep. The old proxy, bootstrap resolvers and address processor are shut down explicitly after the new state is prepared, shrinking the actual downtime to just the final swap and start.
Notes
serverLockis still held for the whole operation (it serializes request handling). A full fix would build the new proxy outside the lock and only swap under a brief critical section; that is left as a follow-up sincePreparecurrently mutates many fields ofs.go build ./...andgo test ./internal/dnsforward/pass; smoke-tested by triggeringPOST /control/dns_configand observing the reconfiguration complete in ~2 ms with DNS resolution continuing afterwards.Signed-off-by: Chen Yun <zouminchen09@gmail .com>