fix dns race condition

.drone.yml

@@ -12,7 +12,7 @@ steps:
 
 trigger:
   event:
-    - push
+    - pull_request
 
 ---
 kind: pipeline
@@ -20,6 +20,11 @@ type: docker
 name: deploy
 
 steps:
+  - name: run tests
+    image: golang
+    commands:
+      - go build
+      - go test -p 1 -v ./...
   - name: docker
     image: plugins/docker
     settings:

test/dns_test.go

@@ -21,10 +21,10 @@ func destroy(conn *sql.DB, path string) {
 }
 
 func randomPort() int {
-	return rand.Intn(3000) + 10000
+	return rand.Intn(3000) + 1024
 }
 
-func setup() (*sql.DB, *dns.Server, int, *string, func()) {
+func setup() (*sql.DB, *dns.Server, *string, *sync.Mutex, func()) {
 	randomDb := utils.RandomId()
 	dnsPort := randomPort()
 
@@ -35,32 +35,35 @@ func setup() (*sql.DB, *dns.Server, int, *string, func()) {
 	}
 	database.FindOrSaveUser(testDb, testUser)
 
+	waitLock := &sync.Mutex{}
 	server := hcdns.MakeServer(&args.Arguments{
 		DnsPort: dnsPort,
 	}, testDb)
+	server.NotifyStartedFunc = func() {
+		waitLock.Unlock()
+	}
+	waitLock.Lock()
 
-	waitGroup := sync.WaitGroup{}
-	waitGroup.Add(1)
 	go func() {
 		server.ListenAndServe()
-		waitGroup.Done()
 	}()
+	waitLock.Lock()
 
 	address := fmt.Sprintf("127.0.0.1:%d", dnsPort)
-	return testDb, server, dnsPort, &address, func() {
+	return testDb, server, &address, waitLock, func() {
+		server.Shutdown()
+
 		testDb.Close()
 		os.Remove(randomDb)
-
-		server.Shutdown()
-		waitGroup.Wait()
 	}
 }
 
 func TestWhenCNAMEIsResolved(t *testing.T) {
 	t.Log("TestWhenCNAMEIsResolved")
 
-	testDb, _, _, addr, cleanup := setup()
+	testDb, _, addr, lock, cleanup := setup()
 	defer cleanup()
+	defer lock.Unlock()
 
 	cname := &database.DNSRecord{
 		ID:       "1",
@@ -85,8 +88,8 @@ func TestWhenCNAMEIsResolved(t *testing.T) {
 
 	qtype := dns.TypeA
 	domain := dns.Fqdn(cname.Name)
-	client := new(dns.Client)
-	message := new(dns.Msg)
+	client := &dns.Client{}
+	message := &dns.Msg{}
 	message.SetQuestion(domain, qtype)
 
 	in, _, err := client.Exchange(message, *addr)
@@ -135,13 +138,14 @@ func TestWhenCNAMEIsResolved(t *testing.T) {
 func TestWhenNoRecordNxDomain(t *testing.T) {
 	t.Log("TestWhenNoRecordNxDomain")
 
-	_, _, _, addr, cleanup := setup()
+	_, _, addr, lock, cleanup := setup()
 	defer cleanup()
+	defer lock.Unlock()
 
 	qtype := dns.TypeA
 	domain := dns.Fqdn("nonexistant.example.com.")
-	client := new(dns.Client)
-	message := new(dns.Msg)
+	client := &dns.Client{}
+	message := &dns.Msg{}
 	message.SetQuestion(domain, qtype)
 
 	in, _, err := client.Exchange(message, *addr)
@@ -162,8 +166,9 @@ func TestWhenNoRecordNxDomain(t *testing.T) {
 func TestWhenUnresolvingCNAME(t *testing.T) {
 	t.Log("TestWhenUnresolvingCNAME")
 
-	testDb, _, _, addr, cleanup := setup()
+	testDb, _, addr, lock, cleanup := setup()
 	defer cleanup()
+	defer lock.Unlock()
 
 	cname := &database.DNSRecord{
 		ID:       "1",
@@ -178,8 +183,8 @@ func TestWhenUnresolvingCNAME(t *testing.T) {
 
 	qtype := dns.TypeA
 	domain := dns.Fqdn(cname.Name)
-	client := new(dns.Client)
-	message := new(dns.Msg)
+	client := &dns.Client{}
+	message := &dns.Msg{}
 	message.SetQuestion(domain, qtype)
 
 	in, _, err := client.Exchange(message, *addr)
@@ -216,8 +221,9 @@ func TestWhenUnresolvingCNAME(t *testing.T) {
 func TestWhenUnresolvingCNAMEWithMaxDepth(t *testing.T) {
 	t.Log("TestWhenUnresolvingCNAMEWithMaxDepth")
 
-	testDb, _, _, addr, cleanup := setup()
+	testDb, _, addr, lock, cleanup := setup()
 	defer cleanup()
+	defer lock.Unlock()
 
 	cname := &database.DNSRecord{
 		ID:       "1",
@@ -232,8 +238,8 @@ func TestWhenUnresolvingCNAMEWithMaxDepth(t *testing.T) {
 
 	qtype := dns.TypeA
 	domain := dns.Fqdn(cname.Name)
-	client := new(dns.Client)
-	message := new(dns.Msg)
+	client := &dns.Client{}
+	message := &dns.Msg{}
 	message.SetQuestion(domain, qtype)
 
 	in, _, err := client.Exchange(message, *addr)
@@ -245,6 +251,7 @@ func TestWhenUnresolvingCNAMEWithMaxDepth(t *testing.T) {
 	if len(in.Answer) > 0 {
 		t.Fatalf("expected 0 answers, got %d", len(in.Answer))
 	}
+
 	if in.Rcode != dns.RcodeServerFailure {
 		t.Fatalf("expected SERVFAIL, got %d", in.Rcode)
 	}