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p2p/discover: remove hot-spin in table refresh trigger #32912

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merged 1 commit into from
Oct 15, 2025
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p2p/discover: remove hot-spin in table refresh trigger #32912

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23 changes: 23 additions & 0 deletions p2p/discover/lookup.go
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Original file line number Diff line number Diff line change
Expand Up @@ -153,6 +153,7 @@ type lookupIterator struct {
cancel func()
lookup *lookup
tabRefreshing <-chan struct{}
lastLookup time.Time
}

type lookupFunc func(ctx context.Context) *lookup
Expand Down Expand Up @@ -185,6 +186,9 @@ func (it *lookupIterator) Next() bool {
return false
}
if it.lookup == nil {
// Ensure enough time has passed between lookup creations.
it.slowdown()

it.lookup = it.nextLookup(it.ctx)
if it.lookup.empty() {
// If the lookup is empty right after creation, it means the local table
Expand Down Expand Up @@ -235,6 +239,25 @@ func (it *lookupIterator) lookupFailed(tab *Table, timeout time.Duration) {
tab.waitForNodes(tout, 1)
}

// slowdown applies a delay between creating lookups. This exists to prevent hot-spinning
// in some test environments where lookups don't yield any results.
func (it *lookupIterator) slowdown() {
const minInterval = 1 * time.Second

now := time.Now()
diff := now.Sub(it.lastLookup)
it.lastLookup = now
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just nitpicking, but something like the following would be more precise:
defer func() { it.lastLookup = time.Now() }()

Anyway, the current one works as well for the scope here.

if diff > minInterval {
return
}
wait := time.NewTimer(diff)
defer wait.Stop()
select {
case <-wait.C:
case <-it.ctx.Done():
}
}

// Close ends the iterator.
func (it *lookupIterator) Close() {
it.cancel()
Expand Down