After a SIGHUP-driven panel restart (which is exactly what the frontend
triggers after a successful DB import via /panel/setting/restartPanel),
the previous implementation deadlocked:
1. server.Stop() called StopTrafficWriter — cancels the context and waits
for the consumer goroutine to exit. The goroutine dies.
2. server.Start() called StartTrafficWriter, but sync.Once had already
fired, so it was a no-op. twQueue still pointed to the old channel
with no consumer.
3. startTask() → RestartXray(true) → GetXrayConfig() →
InboundService.AddTraffic(nil, nil) → submitTrafficWrite. The send
to twQueue succeeded (buffer space) but <-req.done blocked forever
because no goroutine was draining the channel.
4. RestartXray held the global xray lock for the entire hang, so every
subsequent restart attempt from the panel UI also blocked on
lock.Lock(). User-visible symptom: xray stopped silently after DB
import and no panel action could revive it.
Replace sync.Once with a mutex-guarded Start that spawns a fresh
goroutine on each cycle, and a Stop that resets the package state so
the next Start works. runTrafficWriter now takes its channels as
parameters instead of reading package vars, so the old goroutine can't
interfere with a new one if their lifetimes briefly overlap.
MHSanaei
8f3202f431