package helpers import ( "errors" "time" "github.com/ethereum/go-ethereum/p2p" "github.com/ethereum/go-ethereum/p2p/enode" ) var ( // ErrNoRunningNode node is not running. ErrNoRunningNode = errors.New("there is no running node") // ErrEmptyPeerURL provided peer URL is empty ErrEmptyPeerURL = errors.New("empty peer url") ) // waitForPeer waits for a peer to be added func waitForPeer(p *p2p.Server, u string, e p2p.PeerEventType, t time.Duration, subscribed chan struct{}) error { if p == nil { return ErrNoRunningNode } if u == "" { return ErrEmptyPeerURL } parsedPeer, err := enode.ParseV4(u) if err != nil { return err } ch := make(chan *p2p.PeerEvent) subscription := p.SubscribeEvents(ch) defer subscription.Unsubscribe() close(subscribed) for { select { case ev := <-ch: if ev.Type == e && ev.Peer == parsedPeer.ID() { return nil } case err := <-subscription.Err(): if err != nil { return err } case <-time.After(t): return errors.New("wait for peer: timeout") } } } // WaitForPeerAsync waits for a peer to be added asynchronously func WaitForPeerAsync(p *p2p.Server, u string, e p2p.PeerEventType, t time.Duration) <-chan error { subscribed := make(chan struct{}) errCh := make(chan error) go func() { errCh <- waitForPeer(p, u, e, t, subscribed) }() <-subscribed return errCh }