Fix all flaky tests

.github/workflows/go-test.yml

@@ -13,6 +13,8 @@ jobs:
         go: ["1.19.x","1.20.x"]
     env:
       COVERAGES: ""
+      GOLOG_LOG_LEVEL: swarm2=debug,basichost=debug,net/identify=debug,autorelay=debug
+      GOTEST_FLAGS: "-timeout 20m -p 1 -v"
     runs-on: ${{ fromJSON(vars[format('UCI_GO_TEST_RUNNER_{0}', matrix.os)] || format('"{0}-latest"', matrix.os)) }}
     name: ${{ matrix.os }} (go ${{ matrix.go }})
     steps:
@@ -46,7 +48,7 @@ jobs:
           # Use -coverpkg=./..., so that we include cross-package coverage.
           # If package ./A imports ./B, and ./A's tests also cover ./B,
           # this means ./B's coverage will be significantly higher than 0%.
-          run: go test -v -shuffle=on -coverprofile=module-coverage.txt -coverpkg=./... ./...
+          run: go test ${{ env.GOTEST_FLAGS }} -shuffle=on -coverprofile=module-coverage.txt -coverpkg=./... ./...
       - name: Run tests (32 bit)
         # can't run 32 bit tests on OSX.
         if: matrix.os != 'macos' &&
@@ -58,19 +60,19 @@ jobs:
         with:
           run: |
             export "PATH=$PATH_386:$PATH"
-            go test -v -shuffle=on ./...
+            go test ${{ env.GOTEST_FLAGS }} -p 1 -v -shuffle=on ./...
       - name: Run tests with race detector
         # speed things up. Windows and OSX VMs are slow
         if: matrix.os == 'ubuntu' &&
           contains(fromJSON(steps.config.outputs.json).skipOSes, matrix.os) == false
         uses: protocol/multiple-go-modules@v1.2
         with:
-          run: go test -v -race ./...
+          run: go test ${{ env.GOTEST_FLAGS }}  -race ./...
       - name: Collect coverage files
         shell: bash
         run: echo "COVERAGES=$(find . -type f -name 'module-coverage.txt' | tr -s '\n' ',' | sed 's/,$//')" >> $GITHUB_ENV
       - name: Upload coverage to Codecov
         uses: codecov/codecov-action@d9f34f8cd5cb3b3eb79b3e4b5dae3a16df499a70 # v3.1.1
         with:
-          files: '${{ env.COVERAGES }}'
+          files: "${{ env.COVERAGES }}"
           env_vars: OS=${{ matrix.os }}, GO=${{ matrix.go }}

config/config.go

@@ -422,7 +422,9 @@ func (cfg *Config) NewNode() (host.Host, error) {
 		ho = routed.Wrap(h, router)
 	}
 	if ar != nil {
-		return autorelay.NewAutoRelayHost(ho, ar), nil
+		arh := autorelay.NewAutoRelayHost(ho, ar)
+		arh.Start()
+		ho = arh
 	}
 	return ho, nil
 }

docs/flaky-tests.md

@@ -0,0 +1,43 @@
+# Debugging Flaky Tests
+
+If a test is flaky in CI it's probably because there's some timing issue. The
+test probably depends on some Go routine making progress in the background and
+polling to see if the expected outcome is achieved.
+
+This will pretty much always work locally because your local machine is likely
+pretty capable and there isn't too many concurrent processes running. In CI, we
+are susceptible to both slower hardware and noisier neighbors. However we can
+mimic this environment locally with
+[cgroups](https://man7.org/linux/man-pages/man7/cgroups.7.html).
+
+# Replicating noisy neighbors
+
+We can limit the amount of CPU time relative to real time a process gets with
+cgroups. This lets us replicate the environment where many other neighboring
+processes are vying for CPU time.
+
+```bash
+  # Compile some test we want to run. We do this outside the cgroup so this is
+  # fast
+  go test -c ./p2p/host/autorelay
+
+  # Create the group
+  sudo cgcreate -g cpu:/cpulimit
+
+  # Limit the time to 10,000 microseconds for every 1s
+  sudo cgset -r cpu.cfs_quota_us=10000 cpulimit
+  sudo cgset -r cpu.cfs_period_us=1000000 cpulimit
+
+  # Run a shell with in our limited environemnt
+  sudo cgexec -g cpu:cpulimit bash
+
+  # In the shell, run the test
+  ./autorelay.test -test.v
+```
+
+# Flakiness with coverage profile
+
+Sometimes adding the `-coverprofile=module-coverage.txt` introduces flaky
+behavior since it adds another goroutine to the mix. If you're having trouble
+reproducing a flaky test, try enabling this flag.
+

examples/chat/chat_test.go

@@ -6,6 +6,7 @@ import (
 	"fmt"
 	"log"
 	"testing"
+	"time"
 
 	"github.com/libp2p/go-libp2p/core/network"
 
@@ -43,6 +44,8 @@ func TestMain(t *testing.T) {
 
 		go startPeer(ctx, h1, func(network.Stream) {
 			log.Println("Got a new stream!")
+			// Sleep a bit to let h2 print the logs we're waiting for
+			time.Sleep(500 * time.Millisecond)
 			cancel() // end the test
 		})
 

examples/go.mod

@@ -72,7 +72,7 @@ require (
 	github.com/multiformats/go-multibase v0.1.1 // indirect
 	github.com/multiformats/go-multicodec v0.7.0 // indirect
 	github.com/multiformats/go-multihash v0.2.1 // indirect
-	github.com/multiformats/go-multistream v0.4.0 // indirect
+	github.com/multiformats/go-multistream v0.4.1 // indirect
 	github.com/multiformats/go-varint v0.0.7 // indirect
 	github.com/onsi/ginkgo/v2 v2.5.1 // indirect
 	github.com/opencontainers/runtime-spec v1.0.2 // indirect
@@ -111,3 +111,5 @@ require (
 	lukechampine.com/blake3 v1.1.7 // indirect
 	nhooyr.io/websocket v1.8.7 // indirect
 )
+
+replace github.com/libp2p/go-libp2p => ../

examples/go.sum

@@ -310,8 +310,6 @@ github.com/libp2p/go-cidranger v1.1.0 h1:ewPN8EZ0dd1LSnrtuwd4709PXVcITVeuwbag38y
 github.com/libp2p/go-cidranger v1.1.0/go.mod h1:KWZTfSr+r9qEo9OkI9/SIEeAtw+NNoU0dXIXt15Okic=
 github.com/libp2p/go-flow-metrics v0.1.0 h1:0iPhMI8PskQwzh57jB9WxIuIOQ0r+15PChFGkx3Q3WM=
 github.com/libp2p/go-flow-metrics v0.1.0/go.mod h1:4Xi8MX8wj5aWNDAZttg6UPmc0ZrnFNsMtpsYUClFtro=
-github.com/libp2p/go-libp2p v0.25.0 h1:ND6Hc6ZYCzC8S++C4mOD7LdPnLXRkNbr12/8FXgUfIo=
-github.com/libp2p/go-libp2p v0.25.0/go.mod h1:vXHmFpcfl+xIGN4qW58Bw3a0/SKGAesr5/T4IuJHE3o=
 github.com/libp2p/go-libp2p-asn-util v0.2.0 h1:rg3+Os8jbnO5DxkC7K/Utdi+DkY3q/d1/1q+8WeNAsw=
 github.com/libp2p/go-libp2p-asn-util v0.2.0/go.mod h1:WoaWxbHKBymSN41hWSq/lGKJEca7TNm58+gGJi2WsLI=
 github.com/libp2p/go-libp2p-kad-dht v0.20.1-0.20230209220319-6c2045abad23 h1:VGjUg3I0gLugtjZKI4kzvPiptmfYhWHK6YGBI4ZI2Cs=
@@ -398,8 +396,8 @@ github.com/multiformats/go-multihash v0.0.13/go.mod h1:VdAWLKTwram9oKAatUcLxBNUj
 github.com/multiformats/go-multihash v0.1.0/go.mod h1:RJlXsxt6vHGaia+S8We0ErjhojtKzPP2AH4+kYM7k84=
 github.com/multiformats/go-multihash v0.2.1 h1:aem8ZT0VA2nCHHk7bPJ1BjUbHNciqZC/d16Vve9l108=
 github.com/multiformats/go-multihash v0.2.1/go.mod h1:WxoMcYG85AZVQUyRyo9s4wULvW5qrI9vb2Lt6evduFc=
-github.com/multiformats/go-multistream v0.4.0 h1:5i4JbawClkbuaX+mIVXiHQYVPxUW+zjv6w7jtSRukxc=
-github.com/multiformats/go-multistream v0.4.0/go.mod h1:BS6ZSYcA4NwYEaIMeCtpJydp2Dc+fNRA6uJMSu/m8+4=
+github.com/multiformats/go-multistream v0.4.1 h1:rFy0Iiyn3YT0asivDUIR05leAdwZq3de4741sbiSdfo=
+github.com/multiformats/go-multistream v0.4.1/go.mod h1:Mz5eykRVAjJWckE2U78c6xqdtyNUEhKSM0Lwar2p77Q=
 github.com/multiformats/go-varint v0.0.1/go.mod h1:3Ls8CIEsrijN6+B7PbrXRPxHRPuXSrVKRY101jdMZYE=
 github.com/multiformats/go-varint v0.0.5/go.mod h1:3Ls8CIEsrijN6+B7PbrXRPxHRPuXSrVKRY101jdMZYE=
 github.com/multiformats/go-varint v0.0.6/go.mod h1:3Ls8CIEsrijN6+B7PbrXRPxHRPuXSrVKRY101jdMZYE=

go.mod

@@ -115,3 +115,7 @@ require (
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 	lukechampine.com/blake3 v1.1.7 // indirect
 )
+
+replace github.com/stretchr/testify => github.com/marcopolo/testify v1.8.1-eventually
+
+replace github.com/benbjohnson/clock => github.com/marcopolo/clock v1.4.0

go.sum

@@ -51,9 +51,6 @@ github.com/alecthomas/units v0.0.0-20190717042225-c3de453c63f4/go.mod h1:ybxpYRF
 github.com/alecthomas/units v0.0.0-20190924025748-f65c72e2690d/go.mod h1:rBZYJk541a8SKzHPHnH3zbiI+7dagKZ0cgpgrD7Fyho=
 github.com/anmitsu/go-shlex v0.0.0-20161002113705-648efa622239/go.mod h1:2FmKhYUyUczH0OGQWaF5ceTx0UBShxjsH6f8oGKYe2c=
 github.com/armon/consul-api v0.0.0-20180202201655-eb2c6b5be1b6/go.mod h1:grANhF5doyWs3UAsr3K4I6qtAmlQcZDesFNEHPZAzj8=
-github.com/benbjohnson/clock v1.1.0/go.mod h1:J11/hYXuz8f4ySSvYwY0FKfm+ezbsZBKZxNJlLklBHA=
-github.com/benbjohnson/clock v1.3.0 h1:ip6w0uFQkncKQ979AypyG0ER7mqUSBdKLOgAle/AT8A=
-github.com/benbjohnson/clock v1.3.0/go.mod h1:J11/hYXuz8f4ySSvYwY0FKfm+ezbsZBKZxNJlLklBHA=
 github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973/go.mod h1:Dwedo/Wpr24TaqPxmxbtue+5NUziq4I4S80YR8gNf3Q=
 github.com/beorn7/perks v1.0.0/go.mod h1:KWe93zE9D1o94FZ5RNwFwVgaQK1VOXiVxmqh+CedLV8=
 github.com/beorn7/perks v1.0.1 h1:VlbKKnNfV8bJzeqoa4cOKqO6bYr3WgKZxO8Z16+hsOM=
@@ -86,7 +83,6 @@ github.com/coreos/go-systemd/v22 v22.5.0/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSV
 github.com/cpuguy83/go-md2man v1.0.10/go.mod h1:SmD6nW6nTyfqj6ABTjUi3V3JVMnlJmwcJI5acqYI6dE=
 github.com/cpuguy83/go-md2man/v2 v2.0.0-20190314233015-f79a8a8ca69d/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsrgA7czyZG/E6dU=
 github.com/cpuguy83/go-md2man/v2 v2.0.0/go.mod h1:maD7wRr/U5Z6m/iR4s+kqSMx2CaBsrgA7czyZG/E6dU=
-github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davidlazar/go-crypto v0.0.0-20200604182044-b73af7476f6c h1:pFUpOrbxDR6AkioZ1ySsx5yxlDQZ8stG2b88gTPxgJU=
@@ -341,6 +337,10 @@ github.com/libp2p/zeroconf/v2 v2.2.0/go.mod h1:fuJqLnUwZTshS3U/bMRJ3+ow/v9oid1n0
 github.com/lunixbochs/vtclean v1.0.0/go.mod h1:pHhQNgMf3btfWnGBVipUOjRYhoOsdGqdm/+2c2E2WMI=
 github.com/magiconair/properties v1.8.0/go.mod h1:PppfXfuXeibc/6YijjN8zIbojt8czPbwD3XqdrwzmxQ=
 github.com/mailru/easyjson v0.0.0-20190312143242-1de009706dbe/go.mod h1:C1wdFJiN94OJF2b5HbByQZoLdCWB1Yqtg26g4irojpc=
+github.com/marcopolo/clock v1.4.0 h1:kL3wgpJFTB1Zm6SQJkLQMwRV5zPqnPSgz7Lw37H83OI=
+github.com/marcopolo/clock v1.4.0/go.mod h1:J11/hYXuz8f4ySSvYwY0FKfm+ezbsZBKZxNJlLklBHA=
+github.com/marcopolo/testify v1.8.1-eventually h1:TjSolYXOjPglz+qXKyaWjnr+UAq85vDg5PoZGA9WHlQ=
+github.com/marcopolo/testify v1.8.1-eventually/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
 github.com/marten-seemann/tcp v0.0.0-20210406111302-dfbc87cc63fd h1:br0buuQ854V8u83wA0rVZ8ttrq5CpaPZdvrK0LP2lOk=
 github.com/marten-seemann/tcp v0.0.0-20210406111302-dfbc87cc63fd/go.mod h1:QuCEs1Nt24+FYQEqAAncTDPJIuGs+LxK1MCiFL25pMU=
 github.com/mattn/go-isatty v0.0.12/go.mod h1:cbi8OIDigv2wuxKPP5vlRcQ1OAZbq2CE4Kysco4FUpU=
@@ -516,19 +516,8 @@ github.com/spf13/cobra v0.0.5/go.mod h1:3K3wKZymM7VvHMDS9+Akkh4K60UwM26emMESw8tL
 github.com/spf13/jwalterweatherman v1.0.0/go.mod h1:cQK4TGJAtQXfYWX+Ddv3mKDzgVb68N+wFjFa4jdeBTo=
 github.com/spf13/pflag v1.0.3/go.mod h1:DYY7MBk1bdzusC3SYhjObp+wFpr4gzcvqqNjLnInEg4=
 github.com/spf13/viper v1.3.2/go.mod h1:ZiWeW+zYFKm7srdB9IoDzzZXaJaI5eL9QjNiN/DMA2s=
-github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
 github.com/stretchr/objx v0.1.1/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
-github.com/stretchr/objx v0.4.0/go.mod h1:YvHI0jy2hoMjB+UWwv71VJQ9isScKT/TqJzVSSt89Yw=
 github.com/stretchr/objx v0.5.0/go.mod h1:Yh+to48EsGEfYuaHDzXPcE3xhTkx73EhmCGUpEOglKo=
-github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
-github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UVUgZn+9EI=
-github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
-github.com/stretchr/testify v1.5.1/go.mod h1:5W2xD1RspED5o8YsWQXVCued0rvSQ+mT+I5cxcmMvtA=
-github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
-github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
-github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
-github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
-github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
 github.com/syndtr/goleveldb v1.0.0 h1:fBdIW9lB4Iz0n9khmH8w27SJ3QEJ7+IgjPEwGSZiFdE=
 github.com/syndtr/goleveldb v1.0.0/go.mod h1:ZVVdQEZoIme9iO1Ch2Jdy24qqXrMMOU6lpPAyBWyWuQ=
 github.com/tarm/serial v0.0.0-20180830185346-98f6abe2eb07/go.mod h1:kDXzergiv9cbyO7IOYJZWg1U88JhDg3PB6klq9Hg2pA=
@@ -938,7 +927,6 @@ gopkg.in/yaml.v2 v2.2.8/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.3.0/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=
 gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
 gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
-gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.0-20210107192922-496545a6307b/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

p2p/host/autonat/autonat_test.go

@@ -193,7 +193,7 @@ func TestAutoNATIncomingEvents(t *testing.T) {
 
 	require.Eventually(t, func() bool {
 		return an.Status() != network.ReachabilityUnknown
-	}, 500*time.Millisecond, 10*time.Millisecond, "Expected probe due to identification of autonat service")
+	}, 5*time.Second, 100*time.Millisecond, "Expected probe due to identification of autonat service")
 }
 
 func TestAutoNATObservationRecording(t *testing.T) {

p2p/host/autonat/svc_test.go

@@ -10,6 +10,7 @@ import (
 	"github.com/libp2p/go-libp2p/core/host"
 	"github.com/libp2p/go-libp2p/core/network"
 	bhost "github.com/libp2p/go-libp2p/p2p/host/blank"
+	"github.com/libp2p/go-libp2p/p2p/net/swarm"
 	swarmt "github.com/libp2p/go-libp2p/p2p/net/swarm/testing"
 
 	ma "github.com/multiformats/go-multiaddr"
@@ -44,6 +45,7 @@ func makeAutoNATClient(t *testing.T) (host.Host, Client) {
 
 // Note: these tests assume that the host has only private network addresses!
 func TestAutoNATServiceDialRefused(t *testing.T) {
+	defer swarm.SwapDefaultPerPeerRateLimit(swarm.SwapDefaultPerPeerRateLimit(8))
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
@@ -69,6 +71,7 @@ func TestAutoNATServiceDialRefused(t *testing.T) {
 }
 
 func TestAutoNATServiceDialSuccess(t *testing.T) {
+	defer swarm.SwapDefaultPerPeerRateLimit(swarm.SwapDefaultPerPeerRateLimit(8))
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
@@ -89,15 +92,16 @@ func TestAutoNATServiceDialSuccess(t *testing.T) {
 }
 
 func TestAutoNATServiceDialRateLimiter(t *testing.T) {
+	defer swarm.SwapDefaultPerPeerRateLimit(swarm.SwapDefaultPerPeerRateLimit(8))
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
 	c := makeAutoNATConfig(t)
 	defer c.host.Close()
 	defer c.dialer.Close()
 
-	c.dialTimeout = 200 * time.Millisecond
-	c.throttleResetPeriod = 200 * time.Millisecond
+	c.dialTimeout = 10 * time.Second
+	c.throttleResetPeriod = 1 * time.Second
 	c.throttleResetJitter = 0
 	c.throttlePeerMax = 1
 	_ = makeAutoNATService(t, c)
@@ -122,21 +126,22 @@ func TestAutoNATServiceDialRateLimiter(t *testing.T) {
 
 	time.Sleep(400 * time.Millisecond)
 
-	_, err = ac.DialBack(ctx, c.host.ID())
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.Eventually(t, func() bool {
+		_, err = ac.DialBack(ctx, c.host.ID())
+		return err == nil
+	}, 5*time.Second, time.Second)
 }
 
 func TestAutoNATServiceGlobalLimiter(t *testing.T) {
+	defer swarm.SwapDefaultPerPeerRateLimit(swarm.SwapDefaultPerPeerRateLimit(8))
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
 	c := makeAutoNATConfig(t)
 	defer c.host.Close()
 	defer c.dialer.Close()
 
-	c.dialTimeout = time.Second
+	c.dialTimeout = 3 * time.Second
 	c.throttleResetPeriod = 10 * time.Second
 	c.throttleResetJitter = 0
 	c.throttlePeerMax = 1
@@ -169,6 +174,7 @@ func TestAutoNATServiceGlobalLimiter(t *testing.T) {
 }
 
 func TestAutoNATServiceRateLimitJitter(t *testing.T) {
+	defer swarm.SwapDefaultPerPeerRateLimit(swarm.SwapDefaultPerPeerRateLimit(8))
 	c := makeAutoNATConfig(t)
 	defer c.host.Close()
 	defer c.dialer.Close()
@@ -194,6 +200,7 @@ func TestAutoNATServiceRateLimitJitter(t *testing.T) {
 }
 
 func TestAutoNATServiceStartup(t *testing.T) {
+	defer swarm.SwapDefaultPerPeerRateLimit(swarm.SwapDefaultPerPeerRateLimit(8))
 	h := bhost.NewBlankHost(swarmt.GenSwarm(t))
 	defer h.Close()
 	dh := bhost.NewBlankHost(swarmt.GenSwarm(t))

p2p/host/autorelay/autorelay.go

@@ -49,12 +49,15 @@ func NewAutoRelay(bhost *basic.BasicHost, opts ...Option) (*AutoRelay, error) {
 	r.relayFinder = newRelayFinder(bhost, conf.peerSource, &conf)
 	bhost.AddrsFactory = r.hostAddrs
 
+	return r, nil
+}
+
+func (r *AutoRelay) Start() {
 	r.refCount.Add(1)
 	go func() {
 		defer r.refCount.Done()
 		r.background()
 	}()
-	return r, nil
 }
 
 func (r *AutoRelay) background() {