chore: Remove fragile nats port assignment loop

This resolves observed race conditions when running test suites that
utilize the launcher. It also reduces test times considerably, by
eliminating a slow loop to find a port.

cmd/influxd/launcher/launcher.go

@@ -1036,48 +1036,13 @@ func (m *Launcher) run(ctx context.Context) (err error) {
 
 	// NATS streaming server
 	natsOpts := nats.NewDefaultServerOptions()
-
-	// Welcome to ghetto land. It doesn't seem possible to tell NATS to initialise
-	// a random port. In some integration-style tests, this launcher gets initialised
-	// multiple times, and sometimes the port from the previous instantiation is
-	// still open.
-	//
-	// This atrocity checks if the port is free, and if it's not, moves on to the
-	// next one. This best-effort approach may still fail occasionally when, for example,
-	// two tests race on isAddressPortAvailable.
-	var total int
-	for {
-		portAvailable, err := isAddressPortAvailable(natsOpts.Host, natsOpts.Port)
-		if err != nil {
-			return err
-		}
-		if portAvailable && natsOpts.Host == "" {
-			// Double-check localhost to accommodate tests
-			time.Sleep(100 * time.Millisecond)
-			portAvailable, err = isAddressPortAvailable("localhost", natsOpts.Port)
-			if err != nil {
-				return err
-			}
-		}
-		if portAvailable {
-			break
-		}
-
-		time.Sleep(100 * time.Millisecond)
-		natsOpts.Port++
-		total++
-		if total > 50 {
-			return errors.New("unable to find free port for Nats server")
-		}
-	}
+	natsOpts.Port = nats.RandomPort
 	m.natsServer = nats.NewServer(&natsOpts)
-	m.natsPort = natsOpts.Port
-
 	if err := m.natsServer.Open(); err != nil {
 		m.log.Error("Failed to start nats streaming server", zap.Error(err))
 		return err
 	}
-
+	m.natsPort = natsOpts.Port // updated with random port
 	publisher := nats.NewAsyncPublisher(m.log, fmt.Sprintf("nats-publisher-%d", m.natsPort), m.NatsURL())
 	if err := publisher.Open(); err != nil {
 		m.log.Error("Failed to connect to streaming server", zap.Error(err))
@@ -1557,18 +1522,6 @@ func checkForPriorVersion(ctx context.Context, log *zap.Logger, boltPath string,
 	return nil
 }
 
-// isAddressPortAvailable checks whether the address:port is available to listen,
-// by using net.Listen to verify that the port opens successfully, then closes the listener.
-func isAddressPortAvailable(address string, port int) (bool, error) {
-	if l, err := net.Listen("tcp", fmt.Sprintf("%s:%d", address, port)); err == nil {
-		if err := l.Close(); err != nil {
-			return false, err
-		}
-		return true, nil
-	}
-	return false, nil
-}
-
 // OrganizationService returns the internal organization service.
 func (m *Launcher) OrganizationService() platform.OrganizationService {
 	return m.apibackend.OrganizationService

go.mod

@@ -125,3 +125,5 @@ require (
 // if that version does not include PR 8112. In that event, someone (perhaps Mark R again)
 // will need to apply the change in 8112 on top of the newer version of Arrow.
 replace github.com/apache/arrow/go/arrow v0.0.0-20191024131854-af6fa24be0db => github.com/influxdata/arrow/go/arrow v0.0.0-20200917142114-986e413c1705
+
+replace github.com/nats-io/nats-streaming-server v0.11.2 => github.com/influxdata/nats-streaming-server v0.11.3-0.20201112040610-c277f7560803

go.sum

@@ -332,6 +332,8 @@ github.com/influxdata/influxql v0.0.0-20180925231337-1cbfca8e56b6 h1:CFx+pP90q/q
 github.com/influxdata/influxql v0.0.0-20180925231337-1cbfca8e56b6/go.mod h1:KpVI7okXjK6PRi3Z5B+mtKZli+R1DnZgb3N+tzevNgo=
 github.com/influxdata/line-protocol v0.0.0-20180522152040-32c6aa80de5e h1:/o3vQtpWJhvnIbXley4/jwzzqNeigJK9z+LZcJZ9zfM=
 github.com/influxdata/line-protocol v0.0.0-20180522152040-32c6aa80de5e/go.mod h1:4kt73NQhadE3daL3WhR5EJ/J2ocX0PZzwxQ0gXJ7oFE=
+github.com/influxdata/nats-streaming-server v0.11.3-0.20201112040610-c277f7560803 h1:LpaVAM5Www2R7M0GJAxAdL3swBvmna8Pyzw6F7o+j04=
+github.com/influxdata/nats-streaming-server v0.11.3-0.20201112040610-c277f7560803/go.mod h1:qgAMR6M9EokX+R5X7jUQfubwBdS1tBIl4yVJ3shhcWk=
 github.com/influxdata/pkg-config v0.2.5 h1:iC19aXlkUPiwxjxeeKk8TT8S5s3pargNPLgZE/rvOzc=
 github.com/influxdata/pkg-config v0.2.5/go.mod h1:EMS7Ll0S4qkzDk53XS3Z72/egBsPInt+BeRxb0WeSwk=
 github.com/influxdata/promql/v2 v2.12.0/go.mod h1:fxOPu+DY0bqCTCECchSRtWfc+0X19ybifQhZoQNF5D8=
@@ -426,8 +428,6 @@ github.com/nats-io/go-nats v1.7.0 h1:oQOfHcLr8hb43QG8yeVyY2jtarIaTjOv41CGdF3tTvQ
 github.com/nats-io/go-nats v1.7.0/go.mod h1:+t7RHT5ApZebkrQdnn6AhQJmhJJiKAvJUio1PiiCtj0=
 github.com/nats-io/go-nats-streaming v0.4.0 h1:00wOBnTKzZGvQOFRSxj18kUm4X2TvXzv8LS0skZegPc=
 github.com/nats-io/go-nats-streaming v0.4.0/go.mod h1:gfq4R3c9sKAINOpelo0gn/b9QDMBZnmrttcsNF+lqyo=
-github.com/nats-io/nats-streaming-server v0.11.2 h1:UCqZbfXUKs9Ejw7KiNaFZEbbiVbK7uA8jbK2TsdGbqg=
-github.com/nats-io/nats-streaming-server v0.11.2/go.mod h1:RyqtDJZvMZO66YmyjIYdIvS69zu/wDAkyNWa8PIUa5c=
 github.com/nats-io/nkeys v0.0.2 h1:+qM7QpgXnvDDixitZtQUBDY9w/s9mu1ghS+JIbsrx6M=
 github.com/nats-io/nkeys v0.0.2/go.mod h1:dab7URMsZm6Z/jp9Z5UGa87Uutgc2mVpXLC4B7TDb/4=
 github.com/nats-io/nuid v1.0.0 h1:44QGdhbiANq8ZCbUkdn6W5bqtg+mHuDE4wOUuxxndFs=

nats/server.go

@@ -10,6 +10,13 @@ import (
 
 const ServerName = "platform"
 
+const (
+	// RandomPort is the value for port that, when supplied, will cause the
+	// server to listen on a randomly-chosen available port. The resolved port
+	// will be reassigned to the Port field of server.Options.
+	RandomPort = server.RANDOM_PORT
+)
+
 var ErrNoNatsConnection = errors.New("nats connection has not been established. Call Open() first")
 
 // Server wraps a connection to a NATS streaming server