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Merge c0c182f487 into 7a62dddeac

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Kevin Allen 2024-04-27 21:59:53 +08:00 committed by GitHub
parent 7a62dddeac c0c182f487
commit 8d63d9188f
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1 changed files with 8 additions and 1 deletions
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9
net/dnscache/dnscache.go
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@ -163,6 +163,7 @@ func (r *Resolver) ttl() time.Duration {
}
var debug = envknob.RegisterBool("TS_DEBUG_DNS_CACHE")
var noDNSFallback = envknob.RegisterBool("TS_NO_DNS_FALLBACK")
// debugLogging allows enabling debug logging at runtime, via
// SetDebugLoggingEnabled.
@ -296,7 +297,7 @@ func (r *Resolver) lookupIP(host string) (ip, ip6 netip.Addr, allIPs []netip.Add
ips, err = resolver.LookupNetIP(ctx, "ip", host)
}
}
if (err != nil || len(ips) == 0) && r.LookupIPFallback != nil {
if (err != nil || len(ips) == 0) && r.LookupIPFallback != nil && !noDNSFallback() {
ctx, cancel := context.WithTimeout(context.Background(), 30*time.Second)
defer cancel()
if err != nil {
@ -445,6 +446,12 @@ func (d *dialer) shouldTryBootstrap(ctx context.Context, err error, dc *dialCall
d.dnsCache.dlogf("not using bootstrap DNS: no fallback")
return false
}
if noDNSFallback() {
if debug() {
log.Printf("dnscache: not using bootstrap DNS: disabled via TS_NO_DNS_FALLBACK")
}
return false
}
// We can't retry if the context is canceled, since any further
// operations with this context will fail.