portmap integration test: echo server runs in separate process

this way we're not mixing goroutines and namespaces

plugins/meta/portmap/echosvr/echosvr_test.go

@@ -0,0 +1,74 @@
+package main_test
+
+import (
+	"fmt"
+	"io/ioutil"
+	"net"
+	"os/exec"
+	"strings"
+
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+	"github.com/onsi/gomega/gbytes"
+	"github.com/onsi/gomega/gexec"
+)
+
+var binaryPath string
+
+var _ = SynchronizedBeforeSuite(func() []byte {
+	binaryPath, err := gexec.Build("github.com/containernetworking/plugins/plugins/meta/portmap/echosvr")
+	Expect(err).NotTo(HaveOccurred())
+	return []byte(binaryPath)
+}, func(data []byte) {
+	binaryPath = string(data)
+})
+
+var _ = SynchronizedAfterSuite(func() {}, func() {
+	gexec.CleanupBuildArtifacts()
+})
+
+var _ = Describe("Echosvr", func() {
+	var session *gexec.Session
+	BeforeEach(func() {
+		var err error
+		cmd := exec.Command(binaryPath)
+		session, err = gexec.Start(cmd, GinkgoWriter, GinkgoWriter)
+		Expect(err).NotTo(HaveOccurred())
+	})
+
+	AfterEach(func() {
+		session.Terminate().Wait()
+	})
+
+	It("starts and doesn't terminate immediately", func() {
+		Consistently(session).ShouldNot(gexec.Exit())
+	})
+
+	tryConnect := func() (net.Conn, error) {
+		programOutput := session.Out.Contents()
+		addr := strings.TrimSpace(string(programOutput))
+
+		conn, err := net.Dial("tcp", addr)
+		if err != nil {
+			return nil, err
+		}
+		return conn, err
+	}
+
+	It("prints its listening address to stdout", func() {
+		Eventually(session.Out).Should(gbytes.Say("\n"))
+		conn, err := tryConnect()
+		Expect(err).NotTo(HaveOccurred())
+		conn.Close()
+	})
+
+	It("will echo data back to us", func() {
+		Eventually(session.Out).Should(gbytes.Say("\n"))
+		conn, err := tryConnect()
+		Expect(err).NotTo(HaveOccurred())
+		defer conn.Close()
+
+		fmt.Fprintf(conn, "hello")
+		Expect(ioutil.ReadAll(conn)).To(Equal([]byte("hello")))
+	})
+})

plugins/meta/portmap/echosvr/init_test.go

@@ -0,0 +1,13 @@
+package main_test
+
+import (
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+
+	"testing"
+)
+
+func TestEchosvr(t *testing.T) {
+	RegisterFailHandler(Fail)
+	RunSpecs(t, "Echosvr Suite")
+}

plugins/meta/portmap/echosvr/main.go

@@ -0,0 +1,32 @@
+package main
+
+import (
+	"fmt"
+	"net"
+)
+
+func main() {
+	listener, err := net.Listen("tcp", ":")
+	if err != nil {
+		panic(err)
+	}
+	_, port, err := net.SplitHostPort(listener.Addr().String())
+	if err != nil {
+		panic(err)
+	}
+	fmt.Printf("127.0.0.1:%s\n", port)
+	for {
+		conn, err := listener.Accept()
+		if err != nil {
+			panic(err)
+		}
+		go handleConnection(conn)
+	}
+}
+
+func handleConnection(conn net.Conn) {
+	buf := make([]byte, 512)
+	nBytesRead, _ := conn.Read(buf)
+	conn.Write(buf[0:nBytesRead])
+	conn.Close()
+}

plugins/meta/portmap/portmap_integ_test.go

@@ -28,19 +28,20 @@ import (
 	"github.com/coreos/go-iptables/iptables"
 	. "github.com/onsi/ginkgo"
 	. "github.com/onsi/gomega"
+	"github.com/onsi/gomega/gexec"
 	"github.com/vishvananda/netlink"
 )
 
 const TIMEOUT = 90
 
 var _ = Describe("portmap integration tests", func() {
-	rand.Seed(time.Now().UTC().UnixNano())
-
-	var configList *libcni.NetworkConfigList
-	var cniConf *libcni.CNIConfig
-	var targetNS ns.NetNS
-	var containerPort int
-	var closeChan chan interface{}
+	var (
+		configList    *libcni.NetworkConfigList
+		cniConf       *libcni.CNIConfig
+		targetNS      ns.NetNS
+		containerPort int
+		session       *gexec.Session
+	)
 
 	BeforeEach(func() {
 		var err error
@@ -80,12 +81,12 @@ var _ = Describe("portmap integration tests", func() {
 		fmt.Fprintln(GinkgoWriter, "namespace:", targetNS.Path())
 
 		// Start an echo server and get the port
-		containerPort, closeChan, err = RunEchoServerInNS(targetNS)
+		containerPort, session, err = StartEchoServerInNamespace(targetNS)
 		Expect(err).NotTo(HaveOccurred())
-
 	})
 
 	AfterEach(func() {
+		session.Terminate().Wait()
 		if targetNS != nil {
 			targetNS.Close()
 		}
@@ -163,7 +164,7 @@ var _ = Describe("portmap integration tests", func() {
 		snatOK := testEchoServer(fmt.Sprintf("%s:%d", "127.0.0.1", hostPort))
 
 		// Cleanup
-		close(closeChan)
+		session.Terminate()
 		err = deleteNetwork()
 		Expect(err).NotTo(HaveOccurred())
 

plugins/meta/portmap/portmap_suite_test.go

@@ -15,89 +15,64 @@
 package main
 
 import (
-	"fmt"
+	"math/rand"
 	"net"
-	"time"
+	"os/exec"
+	"path/filepath"
+	"strconv"
+	"strings"
 
 	"github.com/containernetworking/plugins/pkg/ns"
 
 	. "github.com/onsi/ginkgo"
+	"github.com/onsi/ginkgo/config"
 	. "github.com/onsi/gomega"
+	"github.com/onsi/gomega/gbytes"
+	"github.com/onsi/gomega/gexec"
 
 	"testing"
 )
 
 func TestPortmap(t *testing.T) {
+	rand.Seed(config.GinkgoConfig.RandomSeed)
+
 	RegisterFailHandler(Fail)
 	RunSpecs(t, "portmap Suite")
 }
 
-// OpenEchoServer opens a server that listens until closeChan is closed.
-// It opens on a random port and sends the port number on portChan when
-// the server is up and running. If an error is encountered, closes portChan.
-// If closeChan is closed, closes the socket.
-func OpenEchoServer(portChan chan<- int, closeChan <-chan interface{}) error {
-	laddr, err := net.ResolveTCPAddr("tcp", "0.0.0.0:0")
-	if err != nil {
-		close(portChan)
-		return err
-	}
-	sock, err := net.ListenTCP("tcp", laddr)
-	if err != nil {
-		close(portChan)
-		return err
-	}
-	defer sock.Close()
+var echoServerBinaryPath string
 
-	switch addr := sock.Addr().(type) {
-	case *net.TCPAddr:
-		portChan <- addr.Port
-	default:
-		close(portChan)
-		return fmt.Errorf("addr cast failed!")
-	}
-	for {
-		select {
-		case <-closeChan:
-			break
-		default:
-		}
+var _ = SynchronizedBeforeSuite(func() []byte {
+	binaryPath, err := gexec.Build("github.com/containernetworking/plugins/plugins/meta/portmap/echosvr")
+	Expect(err).NotTo(HaveOccurred())
+	return []byte(binaryPath)
+}, func(data []byte) {
+	echoServerBinaryPath = string(data)
+})
 
-		sock.SetDeadline(time.Now().Add(time.Second))
-		con, err := sock.AcceptTCP()
-		if err != nil {
-			if opErr, ok := err.(*net.OpError); ok && opErr.Timeout() {
-				continue
-			}
-			continue
-		}
+var _ = SynchronizedAfterSuite(func() {}, func() {
+	gexec.CleanupBuildArtifacts()
+})
 
-		buf := make([]byte, 512)
-		con.Read(buf)
-		con.Write(buf)
-		con.Close()
-	}
+func startInNetNS(binPath string, netNS ns.NetNS) (*gexec.Session, error) {
+	baseName := filepath.Base(netNS.Path())
+	// we are relying on the netNS path living in /var/run/netns
+	// where `ip netns exec` can find it
+	cmd := exec.Command("ip", "netns", "exec", baseName, binPath)
+	session, err := gexec.Start(cmd, GinkgoWriter, GinkgoWriter)
+	return session, err
 }
 
-func RunEchoServerInNS(netNS ns.NetNS) (int, chan interface{}, error) {
-	portChan := make(chan int)
-	closeChan := make(chan interface{})
+func StartEchoServerInNamespace(netNS ns.NetNS) (int, *gexec.Session, error) {
+	session, err := startInNetNS(echoServerBinaryPath, netNS)
+	Expect(err).NotTo(HaveOccurred())
 
-	go func() {
-		err := netNS.Do(func(ns.NetNS) error {
-			OpenEchoServer(portChan, closeChan)
-			return nil
-		})
-		// Somehow the ns.Do failed
-		if err != nil {
-			close(portChan)
-		}
-	}()
+	// wait for it to print it's address on stdout
+	Eventually(session.Out).Should(gbytes.Say("\n"))
+	_, portString, err := net.SplitHostPort(strings.TrimSpace(string(session.Out.Contents())))
+	Expect(err).NotTo(HaveOccurred())
 
-	portNum := <-portChan
-	if portNum == 0 {
-		return 0, nil, fmt.Errorf("failed to execute server")
-	}
-
-	return portNum, closeChan, nil
+	port, err := strconv.Atoi(portString)
+	Expect(err).NotTo(HaveOccurred())
+	return port, session, nil
 }