96 lines
2.6 KiB
Go
96 lines
2.6 KiB
Go
package discovery
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import (
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"context"
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lru "github.com/hashicorp/golang-lru"
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"sync"
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"time"
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"github.com/libp2p/go-libp2p-core/host"
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"github.com/libp2p/go-libp2p-core/peer"
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)
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// BackoffConnector is a utility to connect to peers, but only if we have not recently tried connecting to them already
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type BackoffConnector struct {
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cache *lru.TwoQueueCache
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host host.Host
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connTryDur time.Duration
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backoff BackoffFactory
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mux sync.Mutex
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}
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// NewBackoffConnector creates a utility to connect to peers, but only if we have not recently tried connecting to them already
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// cacheSize is the size of a TwoQueueCache
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// connectionTryDuration is how long we attempt to connect to a peer before giving up
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// backoff describes the strategy used to decide how long to backoff after previously attempting to connect to a peer
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func NewBackoffConnector(h host.Host, cacheSize int, connectionTryDuration time.Duration, backoff BackoffFactory) (*BackoffConnector, error) {
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cache, err := lru.New2Q(cacheSize)
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if err != nil {
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return nil, err
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}
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return &BackoffConnector{
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cache: cache,
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host: h,
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connTryDur: connectionTryDuration,
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backoff: backoff,
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}, nil
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}
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type connCacheData struct {
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nextTry time.Time
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strat BackoffStrategy
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}
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// Connect attempts to connect to the peers passed in by peerCh. Will not connect to peers if they are within the backoff period.
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// As Connect will attempt to dial peers as soon as it learns about them, the caller should try to keep the number,
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// and rate, of inbound peers manageable.
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func (c *BackoffConnector) Connect(ctx context.Context, peerCh <-chan peer.AddrInfo) {
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for {
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select {
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case pi, ok := <-peerCh:
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if !ok {
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return
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}
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if pi.ID == c.host.ID() || pi.ID == "" {
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continue
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}
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c.mux.Lock()
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val, ok := c.cache.Get(pi.ID)
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var cachedPeer *connCacheData
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if ok {
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tv := val.(*connCacheData)
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now := time.Now()
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if now.Before(tv.nextTry) {
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c.mux.Unlock()
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continue
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}
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tv.nextTry = now.Add(tv.strat.Delay())
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} else {
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cachedPeer = &connCacheData{strat: c.backoff()}
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cachedPeer.nextTry = time.Now().Add(cachedPeer.strat.Delay())
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c.cache.Add(pi.ID, cachedPeer)
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}
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c.mux.Unlock()
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go func(pi peer.AddrInfo) {
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ctx, cancel := context.WithTimeout(ctx, c.connTryDur)
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defer cancel()
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err := c.host.Connect(ctx, pi)
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if err != nil {
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log.Debugf("Error connecting to pubsub peer %s: %s", pi.ID, err.Error())
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return
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}
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}(pi)
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case <-ctx.Done():
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log.Infof("discovery: backoff connector context error %v", ctx.Err())
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return
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}
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}
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}
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