Ensure free ports are unique

internal/tests/cog_test.go

@@ -29,11 +29,32 @@ import (
 	"github.com/replicate/cog-runtime/internal/server"
 )
 
+type PortFinder struct {
+	ports map[int]bool
+	mu    sync.Mutex
+}
+
+func (f *PortFinder) Get() int {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	for {
+		a := must.Get(net.ResolveTCPAddr("tcp", "localhost:0"))
+		l := must.Get(net.ListenTCP("tcp", a))
+		p := l.Addr().(*net.TCPAddr).Port
+		if _, ok := f.ports[p]; !ok {
+			f.ports[p] = true
+			l.Close()
+			return p
+		}
+	}
+}
+
 var (
 	_, b, _, _ = runtime.Caller(0)
 	basePath   = path.Dir(path.Dir(path.Dir(b)))
 	logger     = logging.New("cog-test")
 	legacyCog  = flag.Bool("legacy-cog", false, "Test with legacy Cog")
+	portFinder = PortFinder{ports: make(map[int]bool)}
 )
 
 type WebhookRequest struct {
@@ -128,7 +149,7 @@ func (ct *CogTest) Start() error {
 func (ct *CogTest) runtimeCmd() *exec.Cmd {
 	pathEnv := path.Join(basePath, "python", ".venv", "bin")
 	pythonPathEnv := path.Join(basePath, "python")
-	ct.serverPort = getFreePort()
+	ct.serverPort = portFinder.Get()
 	args := []string{
 		"run", path.Join(basePath, "cmd", "cog-server", "main.go"),
 		"--module-name", fmt.Sprintf("tests.runners.%s", ct.module),
@@ -153,7 +174,7 @@ func (ct *CogTest) legacyCmd() *exec.Cmd {
 	must.Do(os.Symlink(path.Join(runnersPath, "cog.yaml"), path.Join(tmpDir, "cog.yaml")))
 	must.Do(os.Symlink(path.Join(runnersPath, module), path.Join(tmpDir, "predict.py")))
 	pythonBin := path.Join(basePath, "python", ".venv-legacy", "bin", "python3")
-	ct.serverPort = getFreePort()
+	ct.serverPort = portFinder.Get()
 	args := []string{
 		"-m", "cog.server.http",
 	}
@@ -175,7 +196,7 @@ func (ct *CogTest) Cleanup() error {
 
 func (ct *CogTest) StartWebhook() {
 	log := logger.Sugar()
-	ct.webhookPort = getFreePort()
+	ct.webhookPort = portFinder.Get()
 	ct.webhookServer = &http.Server{
 		Addr:    fmt.Sprintf(":%d", ct.webhookPort),
 		Handler: &WebhookHandler{},
@@ -324,10 +345,3 @@ func (ct *CogTest) AssertResponse(
 	assert.Equal(ct.t, output, response.Output)
 	assert.Equal(ct.t, logs, response.Logs)
 }
-
-func getFreePort() int {
-	a := must.Get(net.ResolveTCPAddr("tcp", "localhost:0"))
-	l := must.Get(net.ListenTCP("tcp", a))
-	defer l.Close()
-	return l.Addr().(*net.TCPAddr).Port
-}