ceremonyclient/go-libp2p/p2p/host/autorelay/relay_finder.go

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2023-08-21 03:50:38 +00:00
package autorelay
import (
"context"
"errors"
"fmt"
"math/rand"
"sync"
"time"
"golang.org/x/sync/errgroup"
"github.com/libp2p/go-libp2p/core/event"
"github.com/libp2p/go-libp2p/core/network"
"github.com/libp2p/go-libp2p/core/peer"
basic "github.com/libp2p/go-libp2p/p2p/host/basic"
"github.com/libp2p/go-libp2p/p2p/host/eventbus"
circuitv2 "github.com/libp2p/go-libp2p/p2p/protocol/circuitv2/client"
circuitv2_proto "github.com/libp2p/go-libp2p/p2p/protocol/circuitv2/proto"
ma "github.com/multiformats/go-multiaddr"
manet "github.com/multiformats/go-multiaddr/net"
)
const protoIDv2 = circuitv2_proto.ProtoIDv2Hop
// Terminology:
// Candidate: Once we connect to a node and it supports relay protocol,
// we call it a candidate, and consider using it as a relay.
// Relay: Out of the list of candidates, we select a relay to connect to.
// Currently, we just randomly select a candidate, but we can employ more sophisticated
// selection strategies here (e.g. by facotring in the RTT).
const (
rsvpRefreshInterval = time.Minute
rsvpExpirationSlack = 2 * time.Minute
autorelayTag = "autorelay"
)
type candidate struct {
added time.Time
supportsRelayV2 bool
ai peer.AddrInfo
}
// relayFinder is a Host that uses relays for connectivity when a NAT is detected.
type relayFinder struct {
bootTime time.Time
host *basic.BasicHost
conf *config
refCount sync.WaitGroup
ctxCancel context.CancelFunc
ctxCancelMx sync.Mutex
peerSource PeerSource
candidateFound chan struct{} // receives every time we find a new relay candidate
candidateMx sync.Mutex
candidates map[peer.ID]*candidate
backoff map[peer.ID]time.Time
maybeConnectToRelayTrigger chan struct{} // cap: 1
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// Any time _something_ happens that might cause us to need new candidates.
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// This could be
// * the disconnection of a relay
// * the failed attempt to obtain a reservation with a current candidate
// * a candidate is deleted due to its age
maybeRequestNewCandidates chan struct{} // cap: 1.
relayUpdated chan struct{}
relayMx sync.Mutex
relays map[peer.ID]*circuitv2.Reservation
cachedAddrs []ma.Multiaddr
cachedAddrsExpiry time.Time
// A channel that triggers a run of `runScheduledWork`.
triggerRunScheduledWork chan struct{}
metricsTracer MetricsTracer
}
var errAlreadyRunning = errors.New("relayFinder already running")
func newRelayFinder(host *basic.BasicHost, peerSource PeerSource, conf *config) *relayFinder {
if peerSource == nil {
panic("Can not create a new relayFinder. Need a Peer Source fn or a list of static relays. Refer to the documentation around `libp2p.EnableAutoRelay`")
}
return &relayFinder{
bootTime: conf.clock.Now(),
host: host,
conf: conf,
peerSource: peerSource,
candidates: make(map[peer.ID]*candidate),
backoff: make(map[peer.ID]time.Time),
candidateFound: make(chan struct{}, 1),
maybeConnectToRelayTrigger: make(chan struct{}, 1),
maybeRequestNewCandidates: make(chan struct{}, 1),
triggerRunScheduledWork: make(chan struct{}, 1),
relays: make(map[peer.ID]*circuitv2.Reservation),
relayUpdated: make(chan struct{}, 1),
metricsTracer: &wrappedMetricsTracer{conf.metricsTracer},
}
}
type scheduledWorkTimes struct {
leastFrequentInterval time.Duration
nextRefresh time.Time
nextBackoff time.Time
nextOldCandidateCheck time.Time
nextAllowedCallToPeerSource time.Time
}
func (rf *relayFinder) background(ctx context.Context) {
peerSourceRateLimiter := make(chan struct{}, 1)
rf.refCount.Add(1)
go func() {
defer rf.refCount.Done()
rf.findNodes(ctx, peerSourceRateLimiter)
}()
rf.refCount.Add(1)
go func() {
defer rf.refCount.Done()
rf.handleNewCandidates(ctx)
}()
subConnectedness, err := rf.host.EventBus().Subscribe(new(event.EvtPeerConnectednessChanged), eventbus.Name("autorelay (relay finder)"))
if err != nil {
log.Error("failed to subscribe to the EvtPeerConnectednessChanged")
return
}
defer subConnectedness.Close()
now := rf.conf.clock.Now()
bootDelayTimer := rf.conf.clock.InstantTimer(now.Add(rf.conf.bootDelay))
defer bootDelayTimer.Stop()
// This is the least frequent event. It's our fallback timer if we don't have any other work to do.
leastFrequentInterval := rf.conf.minInterval
// Check if leastFrequentInterval is 0 to avoid busy looping
if rf.conf.backoff > leastFrequentInterval || leastFrequentInterval == 0 {
leastFrequentInterval = rf.conf.backoff
}
if rf.conf.maxCandidateAge > leastFrequentInterval || leastFrequentInterval == 0 {
leastFrequentInterval = rf.conf.maxCandidateAge
}
if rsvpRefreshInterval > leastFrequentInterval || leastFrequentInterval == 0 {
leastFrequentInterval = rsvpRefreshInterval
}
scheduledWork := &scheduledWorkTimes{
leastFrequentInterval: leastFrequentInterval,
nextRefresh: now.Add(rsvpRefreshInterval),
nextBackoff: now.Add(rf.conf.backoff),
nextOldCandidateCheck: now.Add(rf.conf.maxCandidateAge),
nextAllowedCallToPeerSource: now.Add(-time.Second), // allow immediately
}
workTimer := rf.conf.clock.InstantTimer(rf.runScheduledWork(ctx, now, scheduledWork, peerSourceRateLimiter))
defer workTimer.Stop()
for {
select {
case ev, ok := <-subConnectedness.Out():
if !ok {
return
}
evt := ev.(event.EvtPeerConnectednessChanged)
if evt.Connectedness != network.NotConnected {
continue
}
push := false
rf.relayMx.Lock()
if rf.usingRelay(evt.Peer) { // we were disconnected from a relay
log.Debugw("disconnected from relay", "id", evt.Peer)
delete(rf.relays, evt.Peer)
rf.notifyMaybeConnectToRelay()
rf.notifyMaybeNeedNewCandidates()
push = true
}
rf.relayMx.Unlock()
if push {
rf.clearCachedAddrsAndSignalAddressChange()
rf.metricsTracer.ReservationEnded(1)
}
case <-rf.candidateFound:
rf.notifyMaybeConnectToRelay()
case <-bootDelayTimer.Ch():
rf.notifyMaybeConnectToRelay()
case <-rf.relayUpdated:
rf.clearCachedAddrsAndSignalAddressChange()
case now := <-workTimer.Ch():
// Note: `now` is not guaranteed to be the current time. It's the time
// that the timer was fired. This is okay because we'll schedule
// future work at a specific time.
nextTime := rf.runScheduledWork(ctx, now, scheduledWork, peerSourceRateLimiter)
workTimer.Reset(nextTime)
case <-rf.triggerRunScheduledWork:
// Ignore the next time because we aren't scheduling any future work here
_ = rf.runScheduledWork(ctx, rf.conf.clock.Now(), scheduledWork, peerSourceRateLimiter)
case <-ctx.Done():
return
}
}
}
func (rf *relayFinder) clearCachedAddrsAndSignalAddressChange() {
rf.relayMx.Lock()
rf.cachedAddrs = nil
rf.relayMx.Unlock()
rf.host.SignalAddressChange()
rf.metricsTracer.RelayAddressUpdated()
}
func (rf *relayFinder) runScheduledWork(ctx context.Context, now time.Time, scheduledWork *scheduledWorkTimes, peerSourceRateLimiter chan<- struct{}) time.Time {
nextTime := now.Add(scheduledWork.leastFrequentInterval)
if now.After(scheduledWork.nextRefresh) {
scheduledWork.nextRefresh = now.Add(rsvpRefreshInterval)
if rf.refreshReservations(ctx, now) {
rf.clearCachedAddrsAndSignalAddressChange()
}
}
if now.After(scheduledWork.nextBackoff) {
scheduledWork.nextBackoff = rf.clearBackoff(now)
}
if now.After(scheduledWork.nextOldCandidateCheck) {
scheduledWork.nextOldCandidateCheck = rf.clearOldCandidates(now)
}
if now.After(scheduledWork.nextAllowedCallToPeerSource) {
select {
case peerSourceRateLimiter <- struct{}{}:
scheduledWork.nextAllowedCallToPeerSource = now.Add(rf.conf.minInterval)
if scheduledWork.nextAllowedCallToPeerSource.Before(nextTime) {
nextTime = scheduledWork.nextAllowedCallToPeerSource
}
default:
}
} else {
// We still need to schedule this work if it's sooner than nextTime
if scheduledWork.nextAllowedCallToPeerSource.Before(nextTime) {
nextTime = scheduledWork.nextAllowedCallToPeerSource
}
}
// Find the next time we need to run scheduled work.
if scheduledWork.nextRefresh.Before(nextTime) {
nextTime = scheduledWork.nextRefresh
}
if scheduledWork.nextBackoff.Before(nextTime) {
nextTime = scheduledWork.nextBackoff
}
if scheduledWork.nextOldCandidateCheck.Before(nextTime) {
nextTime = scheduledWork.nextOldCandidateCheck
}
if nextTime == now {
// Only happens in CI with a mock clock
nextTime = nextTime.Add(1) // avoids an infinite loop
}
rf.metricsTracer.ScheduledWorkUpdated(scheduledWork)
return nextTime
}
// clearOldCandidates clears old candidates from the map. Returns the next time
// to run this function.
func (rf *relayFinder) clearOldCandidates(now time.Time) time.Time {
// If we don't have any candidates, we should run this again in rf.conf.maxCandidateAge.
nextTime := now.Add(rf.conf.maxCandidateAge)
var deleted bool
rf.candidateMx.Lock()
defer rf.candidateMx.Unlock()
for id, cand := range rf.candidates {
expiry := cand.added.Add(rf.conf.maxCandidateAge)
if expiry.After(now) {
if expiry.Before(nextTime) {
nextTime = expiry
}
} else {
log.Debugw("deleting candidate due to age", "id", id)
deleted = true
rf.removeCandidate(id)
}
}
if deleted {
rf.notifyMaybeNeedNewCandidates()
}
return nextTime
}
// clearBackoff clears old backoff entries from the map. Returns the next time
// to run this function.
func (rf *relayFinder) clearBackoff(now time.Time) time.Time {
nextTime := now.Add(rf.conf.backoff)
rf.candidateMx.Lock()
defer rf.candidateMx.Unlock()
for id, t := range rf.backoff {
expiry := t.Add(rf.conf.backoff)
if expiry.After(now) {
if expiry.Before(nextTime) {
nextTime = expiry
}
} else {
log.Debugw("removing backoff for node", "id", id)
delete(rf.backoff, id)
}
}
return nextTime
}
// findNodes accepts nodes from the channel and tests if they support relaying.
// It is run on both public and private nodes.
// It garbage collects old entries, so that nodes doesn't overflow.
// This makes sure that as soon as we need to find relay candidates, we have them available.
// peerSourceRateLimiter is used to limit how often we call the peer source.
func (rf *relayFinder) findNodes(ctx context.Context, peerSourceRateLimiter <-chan struct{}) {
var peerChan <-chan peer.AddrInfo
var wg sync.WaitGroup
for {
rf.candidateMx.Lock()
numCandidates := len(rf.candidates)
rf.candidateMx.Unlock()
if peerChan == nil && numCandidates < rf.conf.minCandidates {
rf.metricsTracer.CandidateLoopState(peerSourceRateLimited)
select {
case <-peerSourceRateLimiter:
peerChan = rf.peerSource(ctx, rf.conf.maxCandidates)
select {
case rf.triggerRunScheduledWork <- struct{}{}:
default:
}
case <-ctx.Done():
return
}
}
if peerChan == nil {
rf.metricsTracer.CandidateLoopState(waitingForTrigger)
} else {
rf.metricsTracer.CandidateLoopState(waitingOnPeerChan)
}
select {
case <-rf.maybeRequestNewCandidates:
continue
case pi, ok := <-peerChan:
if !ok {
wg.Wait()
peerChan = nil
continue
}
log.Debugw("found node", "id", pi.ID)
rf.candidateMx.Lock()
numCandidates := len(rf.candidates)
backoffStart, isOnBackoff := rf.backoff[pi.ID]
rf.candidateMx.Unlock()
if isOnBackoff {
log.Debugw("skipping node that we recently failed to obtain a reservation with", "id", pi.ID, "last attempt", rf.conf.clock.Since(backoffStart))
continue
}
if numCandidates >= rf.conf.maxCandidates {
log.Debugw("skipping node. Already have enough candidates", "id", pi.ID, "num", numCandidates, "max", rf.conf.maxCandidates)
continue
}
rf.refCount.Add(1)
wg.Add(1)
go func() {
defer rf.refCount.Done()
defer wg.Done()
if added := rf.handleNewNode(ctx, pi); added {
rf.notifyNewCandidate()
}
}()
case <-ctx.Done():
rf.metricsTracer.CandidateLoopState(stopped)
return
}
}
}
func (rf *relayFinder) notifyMaybeConnectToRelay() {
select {
case rf.maybeConnectToRelayTrigger <- struct{}{}:
default:
}
}
func (rf *relayFinder) notifyMaybeNeedNewCandidates() {
select {
case rf.maybeRequestNewCandidates <- struct{}{}:
default:
}
}
func (rf *relayFinder) notifyNewCandidate() {
select {
case rf.candidateFound <- struct{}{}:
default:
}
}
// handleNewNode tests if a peer supports circuit v2.
// This method is only run on private nodes.
// If a peer does, it is added to the candidates map.
// Note that just supporting the protocol doesn't guarantee that we can also obtain a reservation.
func (rf *relayFinder) handleNewNode(ctx context.Context, pi peer.AddrInfo) (added bool) {
rf.relayMx.Lock()
relayInUse := rf.usingRelay(pi.ID)
rf.relayMx.Unlock()
if relayInUse {
return false
}
ctx, cancel := context.WithTimeout(ctx, 20*time.Second)
defer cancel()
supportsV2, err := rf.tryNode(ctx, pi)
if err != nil {
log.Debugf("node %s not accepted as a candidate: %s", pi.ID, err)
if err == errProtocolNotSupported {
rf.metricsTracer.CandidateChecked(false)
}
return false
}
rf.metricsTracer.CandidateChecked(true)
rf.candidateMx.Lock()
if len(rf.candidates) > rf.conf.maxCandidates {
rf.candidateMx.Unlock()
return false
}
log.Debugw("node supports relay protocol", "peer", pi.ID, "supports circuit v2", supportsV2)
rf.addCandidate(&candidate{
added: rf.conf.clock.Now(),
ai: pi,
supportsRelayV2: supportsV2,
})
rf.candidateMx.Unlock()
return true
}
var errProtocolNotSupported = errors.New("doesn't speak circuit v2")
// tryNode checks if a peer actually supports either circuit v2.
// It does not modify any internal state.
func (rf *relayFinder) tryNode(ctx context.Context, pi peer.AddrInfo) (supportsRelayV2 bool, err error) {
if err := rf.host.Connect(ctx, pi); err != nil {
return false, fmt.Errorf("error connecting to relay %s: %w", pi.ID, err)
}
conns := rf.host.Network().ConnsToPeer(pi.ID)
for _, conn := range conns {
if isRelayAddr(conn.RemoteMultiaddr()) {
return false, errors.New("not a public node")
}
}
// wait for identify to complete in at least one conn so that we can check the supported protocols
ready := make(chan struct{}, 1)
for _, conn := range conns {
go func(conn network.Conn) {
select {
case <-rf.host.IDService().IdentifyWait(conn):
select {
case ready <- struct{}{}:
default:
}
case <-ctx.Done():
}
}(conn)
}
select {
case <-ready:
case <-ctx.Done():
return false, ctx.Err()
}
protos, err := rf.host.Peerstore().SupportsProtocols(pi.ID, protoIDv2)
if err != nil {
return false, fmt.Errorf("error checking relay protocol support for peer %s: %w", pi.ID, err)
}
if len(protos) == 0 {
return false, errProtocolNotSupported
}
return true, nil
}
// When a new node that could be a relay is found, we receive a notification on the maybeConnectToRelayTrigger chan.
// This function makes sure that we only run one instance of maybeConnectToRelay at once, and buffers
// exactly one more trigger event to run maybeConnectToRelay.
func (rf *relayFinder) handleNewCandidates(ctx context.Context) {
for {
select {
case <-ctx.Done():
return
case <-rf.maybeConnectToRelayTrigger:
rf.maybeConnectToRelay(ctx)
}
}
}
func (rf *relayFinder) maybeConnectToRelay(ctx context.Context) {
rf.relayMx.Lock()
numRelays := len(rf.relays)
rf.relayMx.Unlock()
// We're already connected to our desired number of relays. Nothing to do here.
if numRelays == rf.conf.desiredRelays {
return
}
rf.candidateMx.Lock()
if len(rf.relays) == 0 && len(rf.candidates) < rf.conf.minCandidates && rf.conf.clock.Since(rf.bootTime) < rf.conf.bootDelay {
// During the startup phase, we don't want to connect to the first candidate that we find.
// Instead, we wait until we've found at least minCandidates, and then select the best of those.
// However, if that takes too long (longer than bootDelay), we still go ahead.
rf.candidateMx.Unlock()
return
}
if len(rf.candidates) == 0 {
rf.candidateMx.Unlock()
return
}
candidates := rf.selectCandidates()
rf.candidateMx.Unlock()
// We now iterate over the candidates, attempting (sequentially) to get reservations with them, until
// we reach the desired number of relays.
for _, cand := range candidates {
id := cand.ai.ID
rf.relayMx.Lock()
usingRelay := rf.usingRelay(id)
rf.relayMx.Unlock()
if usingRelay {
rf.candidateMx.Lock()
rf.removeCandidate(id)
rf.candidateMx.Unlock()
rf.notifyMaybeNeedNewCandidates()
continue
}
rsvp, err := rf.connectToRelay(ctx, cand)
if err != nil {
log.Debugw("failed to connect to relay", "peer", id, "error", err)
rf.notifyMaybeNeedNewCandidates()
rf.metricsTracer.ReservationRequestFinished(false, err)
continue
}
log.Debugw("adding new relay", "id", id)
rf.relayMx.Lock()
rf.relays[id] = rsvp
numRelays := len(rf.relays)
rf.relayMx.Unlock()
rf.notifyMaybeNeedNewCandidates()
rf.host.ConnManager().Protect(id, autorelayTag) // protect the connection
select {
case rf.relayUpdated <- struct{}{}:
default:
}
rf.metricsTracer.ReservationRequestFinished(false, nil)
if numRelays >= rf.conf.desiredRelays {
break
}
}
}
func (rf *relayFinder) connectToRelay(ctx context.Context, cand *candidate) (*circuitv2.Reservation, error) {
id := cand.ai.ID
ctx, cancel := context.WithTimeout(ctx, 10*time.Second)
defer cancel()
var rsvp *circuitv2.Reservation
// make sure we're still connected.
if rf.host.Network().Connectedness(id) != network.Connected {
if err := rf.host.Connect(ctx, cand.ai); err != nil {
rf.candidateMx.Lock()
rf.removeCandidate(cand.ai.ID)
rf.candidateMx.Unlock()
return nil, fmt.Errorf("failed to connect: %w", err)
}
}
rf.candidateMx.Lock()
rf.backoff[id] = rf.conf.clock.Now()
rf.candidateMx.Unlock()
var err error
if cand.supportsRelayV2 {
rsvp, err = circuitv2.Reserve(ctx, rf.host, cand.ai)
if err != nil {
err = fmt.Errorf("failed to reserve slot: %w", err)
}
}
rf.candidateMx.Lock()
rf.removeCandidate(id)
rf.candidateMx.Unlock()
return rsvp, err
}
func (rf *relayFinder) refreshReservations(ctx context.Context, now time.Time) bool {
rf.relayMx.Lock()
// find reservations about to expire and refresh them in parallel
g := new(errgroup.Group)
for p, rsvp := range rf.relays {
if now.Add(rsvpExpirationSlack).Before(rsvp.Expiration) {
continue
}
p := p
g.Go(func() error {
err := rf.refreshRelayReservation(ctx, p)
rf.metricsTracer.ReservationRequestFinished(true, err)
return err
})
}
rf.relayMx.Unlock()
err := g.Wait()
return err != nil
}
func (rf *relayFinder) refreshRelayReservation(ctx context.Context, p peer.ID) error {
rsvp, err := circuitv2.Reserve(ctx, rf.host, peer.AddrInfo{ID: p})
rf.relayMx.Lock()
if err != nil {
log.Debugw("failed to refresh relay slot reservation", "relay", p, "error", err)
_, exists := rf.relays[p]
delete(rf.relays, p)
// unprotect the connection
rf.host.ConnManager().Unprotect(p, autorelayTag)
rf.relayMx.Unlock()
if exists {
rf.metricsTracer.ReservationEnded(1)
}
return err
}
log.Debugw("refreshed relay slot reservation", "relay", p)
rf.relays[p] = rsvp
rf.relayMx.Unlock()
return nil
}
// usingRelay returns if we're currently using the given relay.
func (rf *relayFinder) usingRelay(p peer.ID) bool {
_, ok := rf.relays[p]
return ok
}
// addCandidates adds a candidate to the candidates set. Assumes caller holds candidateMx mutex
func (rf *relayFinder) addCandidate(cand *candidate) {
_, exists := rf.candidates[cand.ai.ID]
rf.candidates[cand.ai.ID] = cand
if !exists {
rf.metricsTracer.CandidateAdded(1)
}
}
func (rf *relayFinder) removeCandidate(id peer.ID) {
_, exists := rf.candidates[id]
if exists {
delete(rf.candidates, id)
rf.metricsTracer.CandidateRemoved(1)
}
}
// selectCandidates returns an ordered slice of relay candidates.
// Callers should attempt to obtain reservations with the candidates in this order.
func (rf *relayFinder) selectCandidates() []*candidate {
now := rf.conf.clock.Now()
candidates := make([]*candidate, 0, len(rf.candidates))
for _, cand := range rf.candidates {
if cand.added.Add(rf.conf.maxCandidateAge).After(now) {
candidates = append(candidates, cand)
}
}
// TODO: better relay selection strategy; this just selects random relays,
// but we should probably use ping latency as the selection metric
rand.Shuffle(len(candidates), func(i, j int) {
candidates[i], candidates[j] = candidates[j], candidates[i]
})
return candidates
}
// This function is computes the NATed relay addrs when our status is private:
// - The public addrs are removed from the address set.
// - The non-public addrs are included verbatim so that peers behind the same NAT/firewall
// can still dial us directly.
// - On top of those, we add the relay-specific addrs for the relays to which we are
// connected. For each non-private relay addr, we encapsulate the p2p-circuit addr
// through which we can be dialed.
func (rf *relayFinder) relayAddrs(addrs []ma.Multiaddr) []ma.Multiaddr {
rf.relayMx.Lock()
defer rf.relayMx.Unlock()
if rf.cachedAddrs != nil && rf.conf.clock.Now().Before(rf.cachedAddrsExpiry) {
return rf.cachedAddrs
}
raddrs := make([]ma.Multiaddr, 0, 4*len(rf.relays)+4)
// only keep private addrs from the original addr set
for _, addr := range addrs {
if manet.IsPrivateAddr(addr) {
raddrs = append(raddrs, addr)
}
}
// add relay specific addrs to the list
relayAddrCnt := 0
for p := range rf.relays {
addrs := cleanupAddressSet(rf.host.Peerstore().Addrs(p))
relayAddrCnt += len(addrs)
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circuit := ma.StringCast(fmt.Sprintf("/p2p/%s/p2p-circuit", p))
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for _, addr := range addrs {
pub := addr.Encapsulate(circuit)
raddrs = append(raddrs, pub)
}
}
rf.cachedAddrs = raddrs
rf.cachedAddrsExpiry = rf.conf.clock.Now().Add(30 * time.Second)
rf.metricsTracer.RelayAddressCount(relayAddrCnt)
return raddrs
}
func (rf *relayFinder) Start() error {
rf.ctxCancelMx.Lock()
defer rf.ctxCancelMx.Unlock()
if rf.ctxCancel != nil {
return errAlreadyRunning
}
log.Debug("starting relay finder")
rf.initMetrics()
ctx, cancel := context.WithCancel(context.Background())
rf.ctxCancel = cancel
rf.refCount.Add(1)
go func() {
defer rf.refCount.Done()
rf.background(ctx)
}()
return nil
}
func (rf *relayFinder) Stop() error {
rf.ctxCancelMx.Lock()
defer rf.ctxCancelMx.Unlock()
log.Debug("stopping relay finder")
if rf.ctxCancel != nil {
rf.ctxCancel()
}
rf.refCount.Wait()
rf.ctxCancel = nil
rf.resetMetrics()
return nil
}
func (rf *relayFinder) initMetrics() {
rf.metricsTracer.DesiredReservations(rf.conf.desiredRelays)
rf.relayMx.Lock()
rf.metricsTracer.ReservationOpened(len(rf.relays))
rf.relayMx.Unlock()
rf.candidateMx.Lock()
rf.metricsTracer.CandidateAdded(len(rf.candidates))
rf.candidateMx.Unlock()
}
func (rf *relayFinder) resetMetrics() {
rf.relayMx.Lock()
rf.metricsTracer.ReservationEnded(len(rf.relays))
rf.relayMx.Unlock()
rf.candidateMx.Lock()
rf.metricsTracer.CandidateRemoved(len(rf.candidates))
rf.candidateMx.Unlock()
rf.metricsTracer.RelayAddressCount(0)
rf.metricsTracer.ScheduledWorkUpdated(&scheduledWorkTimes{})
}