diff --git a/p2p/discover/lookup.go b/p2p/discover/lookup.go index 9cca0118ac..416256fb36 100644 --- a/p2p/discover/lookup.go +++ b/p2p/discover/lookup.go @@ -153,6 +153,7 @@ type lookupIterator struct { cancel func() lookup *lookup tabRefreshing <-chan struct{} + lastLookup time.Time } type lookupFunc func(ctx context.Context) *lookup @@ -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 @@ -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 + 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()