ceremonyclient/go-libp2p/p2p/discovery/backoff/backoffcache_test.go

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2023-08-21 03:50:38 +00:00
package backoff
import (
"context"
"math/rand"
"testing"
"time"
"github.com/libp2p/go-libp2p/p2p/discovery/mocks"
bhost "github.com/libp2p/go-libp2p/p2p/host/blank"
swarmt "github.com/libp2p/go-libp2p/p2p/net/swarm/testing"
"github.com/libp2p/go-libp2p/core/discovery"
"github.com/libp2p/go-libp2p/core/peer"
mockClock "github.com/benbjohnson/clock"
)
type delayedDiscovery struct {
disc discovery.Discovery
delay time.Duration
clock *mockClock.Mock
}
func (d *delayedDiscovery) Advertise(ctx context.Context, ns string, opts ...discovery.Option) (time.Duration, error) {
return d.disc.Advertise(ctx, ns, opts...)
}
func (d *delayedDiscovery) FindPeers(ctx context.Context, ns string, opts ...discovery.Option) (<-chan peer.AddrInfo, error) {
dch, err := d.disc.FindPeers(ctx, ns, opts...)
if err != nil {
return nil, err
}
ch := make(chan peer.AddrInfo, 32)
doneCh := make(chan struct{})
go func() {
defer close(ch)
defer close(doneCh)
for ai := range dch {
ch <- ai
d.clock.Sleep(d.delay)
}
}()
// Tick the clock forward to advance the sleep above
go func() {
for {
select {
case <-doneCh:
return
default:
d.clock.Add(d.delay)
}
}
}()
return ch, nil
}
func assertNumPeers(t *testing.T, ctx context.Context, d discovery.Discovery, ns string, count int) {
t.Helper()
assertNumPeersWithLimit(t, ctx, d, ns, 10, count)
}
func assertNumPeersWithLimit(t *testing.T, ctx context.Context, d discovery.Discovery, ns string, limit int, count int) {
t.Helper()
peerCh, err := d.FindPeers(ctx, ns, discovery.Limit(limit))
if err != nil {
t.Fatal(err)
}
peerset := make(map[peer.ID]struct{})
for p := range peerCh {
peerset[p.ID] = struct{}{}
}
if len(peerset) != count {
t.Fatalf("Was supposed to find %d, found %d instead", count, len(peerset))
}
}
func TestBackoffDiscoverySingleBackoff(t *testing.T) {
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
clock := mockClock.NewMock()
discServer := mocks.NewDiscoveryServer(clock)
h1 := bhost.NewBlankHost(swarmt.GenSwarm(t))
defer h1.Close()
h2 := bhost.NewBlankHost(swarmt.GenSwarm(t))
defer h2.Close()
d1 := mocks.NewDiscoveryClient(h1, discServer)
d2 := mocks.NewDiscoveryClient(h2, discServer)
bkf := NewExponentialBackoff(
time.Millisecond*100,
time.Second*10,
NoJitter,
time.Millisecond*100,
2.5,
0,
rand.NewSource(0),
)
dCache, err := NewBackoffDiscovery(d1, bkf, withClock(clock))
if err != nil {
t.Fatal(err)
}
const ns = "test"
// try adding a peer then find it
d1.Advertise(ctx, ns, discovery.TTL(time.Hour))
// Advance clock by one step
clock.Add(1)
assertNumPeers(t, ctx, dCache, ns, 1)
// add a new peer and make sure it is still hidden by the caching layer
d2.Advertise(ctx, ns, discovery.TTL(time.Hour))
// Advance clock by one step
clock.Add(1)
assertNumPeers(t, ctx, dCache, ns, 1)
// wait for cache to expire and check for the new peer
clock.Add(time.Millisecond * 110)
assertNumPeers(t, ctx, dCache, ns, 2)
}
func TestBackoffDiscoveryMultipleBackoff(t *testing.T) {
clock := mockClock.NewMock()
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
discServer := mocks.NewDiscoveryServer(clock)
h1 := bhost.NewBlankHost(swarmt.GenSwarm(t))
defer h1.Close()
h2 := bhost.NewBlankHost(swarmt.GenSwarm(t))
defer h2.Close()
d1 := mocks.NewDiscoveryClient(h1, discServer)
d2 := mocks.NewDiscoveryClient(h2, discServer)
// Startup delay is 0ms. First backoff after finding data is 100ms, second backoff is 250ms.
bkf := NewExponentialBackoff(
time.Millisecond*100,
time.Second*10,
NoJitter,
time.Millisecond*100,
2.5,
0,
rand.NewSource(0),
)
dCache, err := NewBackoffDiscovery(d1, bkf, withClock(clock))
if err != nil {
t.Fatal(err)
}
const ns = "test"
// try adding a peer then find it
d1.Advertise(ctx, ns, discovery.TTL(time.Hour))
// Advance clock by one step
clock.Add(1)
assertNumPeers(t, ctx, dCache, ns, 1)
// wait a little to make sure the extra request doesn't modify the backoff
clock.Add(time.Millisecond * 50) // 50 < 100
assertNumPeers(t, ctx, dCache, ns, 1)
// wait for backoff to expire and check if we increase it
clock.Add(time.Millisecond * 60) // 50+60 > 100
assertNumPeers(t, ctx, dCache, ns, 1)
d2.Advertise(ctx, ns, discovery.TTL(time.Millisecond*400))
clock.Add(time.Millisecond * 150) // 150 < 250
assertNumPeers(t, ctx, dCache, ns, 1)
clock.Add(time.Millisecond * 150) // 150 + 150 > 250
assertNumPeers(t, ctx, dCache, ns, 2)
// check that the backoff has been reset
// also checks that we can decrease our peer count (i.e. not just growing a set)
clock.Add(time.Millisecond * 110) // 110 > 100, also 150+150+110>400
assertNumPeers(t, ctx, dCache, ns, 1)
}
func TestBackoffDiscoverySimultaneousQuery(t *testing.T) {
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
clock := mockClock.NewMock()
discServer := mocks.NewDiscoveryServer(clock)
// Testing with n larger than most internal buffer sizes (32)
n := 40
advertisers := make([]discovery.Discovery, n)
for i := 0; i < n; i++ {
h := bhost.NewBlankHost(swarmt.GenSwarm(t))
defer h.Close()
advertisers[i] = mocks.NewDiscoveryClient(h, discServer)
}
d1 := &delayedDiscovery{advertisers[0], time.Millisecond * 10, clock}
bkf := NewFixedBackoff(time.Millisecond * 200)
dCache, err := NewBackoffDiscovery(d1, bkf, withClock(clock))
if err != nil {
t.Fatal(err)
}
const ns = "test"
for _, a := range advertisers {
if _, err := a.Advertise(ctx, ns, discovery.TTL(time.Hour)); err != nil {
t.Fatal(err)
}
}
// Advance clock by one step
clock.Add(1)
ch1, err := dCache.FindPeers(ctx, ns)
if err != nil {
t.Fatal(err)
}
<-ch1
ch2, err := dCache.FindPeers(ctx, ns)
if err != nil {
t.Fatal(err)
}
szCh2 := 0
for ai := range ch2 {
_ = ai
szCh2++
}
szCh1 := 1
for range ch1 {
szCh1++
}
if szCh1 != n && szCh2 != n {
t.Fatalf("Channels returned %d, %d elements instead of %d", szCh1, szCh2, n)
}
}
func TestBackoffDiscoveryCacheCapacity(t *testing.T) {
ctx, cancel := context.WithCancel(context.Background())
defer cancel()
clock := mockClock.NewMock()
discServer := mocks.NewDiscoveryServer(clock)
// Testing with n larger than most internal buffer sizes (32)
n := 40
advertisers := make([]discovery.Discovery, n)
for i := 0; i < n; i++ {
h := bhost.NewBlankHost(swarmt.GenSwarm(t))
defer h.Close()
advertisers[i] = mocks.NewDiscoveryClient(h, discServer)
}
h1 := bhost.NewBlankHost(swarmt.GenSwarm(t))
d1 := mocks.NewDiscoveryClient(h1, discServer)
discoveryInterval := time.Millisecond * 10
bkf := NewFixedBackoff(discoveryInterval)
dCache, err := NewBackoffDiscovery(d1, bkf, withClock(clock))
if err != nil {
t.Fatal(err)
}
const ns = "test"
// add speers
for i := 0; i < n; i++ {
advertisers[i].Advertise(ctx, ns, discovery.TTL(time.Hour))
}
// Advance clock by one step
clock.Add(1)
// Request all peers, all will be present
assertNumPeersWithLimit(t, ctx, dCache, ns, n, n)
// Request peers with a lower limit
assertNumPeersWithLimit(t, ctx, dCache, ns, n-1, n-1)
// Wait a little time but don't allow cache to expire
clock.Add(discoveryInterval / 10)
// Request peers with a lower limit this time using cache
// Here we are testing that the cache logic does not block when there are more peers known than the limit requested
// See https://github.com/libp2p/go-libp2p-discovery/issues/67
assertNumPeersWithLimit(t, ctx, dCache, ns, n-1, n-1)
// Wait for next discovery so next request will bypass cache
clock.Add(time.Millisecond * 100)
// Ask for all peers again
assertNumPeersWithLimit(t, ctx, dCache, ns, n, n)
}