Revert "Change hsConn to a map (#50)"

This reverts commit 2d2faf9.

security/s2a/internal/handshaker/service/service.go

@@ -25,11 +25,10 @@ import (
 )
 
 var (
-	// mu guards hsConnMap and hsDialer.
+	// hsConn represents a connection to the S2A handshaker service.
+	hsConn *grpc.ClientConn
+	// mu guards hsDialer.
 	mu sync.Mutex
-	// hsConnMap represents a mapping from an S2A handshaker service address
-	// to a corresponding connection to an S2A handshaker service instance.
-	hsConnMap = make(map[string]*grpc.ClientConn)
 	// hsDialer will be reassigned in tests.
 	hsDialer = grpc.Dial
 )
@@ -41,16 +40,14 @@ func Dial(handshakerServiceAddress string) (*grpc.ClientConn, error) {
 	mu.Lock()
 	defer mu.Unlock()
 
-	hsConn, ok := hsConnMap[handshakerServiceAddress]
-	if !ok {
+	if hsConn == nil {
 		// Create a new connection to the S2A handshaker service. Note that
 		// this connection stays open until the application is closed.
 		var err error
 		hsConn, err = hsDialer(handshakerServiceAddress, grpc.WithInsecure())
 		if err != nil {
 			return nil, err
 		}
-		hsConnMap[handshakerServiceAddress] = hsConn
 	}
 	return hsConn, nil
 }

security/s2a/internal/handshaker/service/service_test.go

@@ -25,8 +25,8 @@ import (
 )
 
 const (
-	testAddress  = "test_address"
-	testAddress2 = "test_address_2"
+	// The address is irrelevant in this test.
+	testAddress = "some_address"
 )
 
 func TestDial(t *testing.T) {
@@ -40,44 +40,30 @@ func TestDial(t *testing.T) {
 		}
 	}()
 
-	// First call to Dial, it should create a connection to the server running
-	// at the given address.
+	// Ensure that hsConn is nil at first.
+	hsConn = nil
+
+	// First call to Dial, it should create set hsConn.
 	conn1, err := Dial(testAddress)
 	if err != nil {
-		t.Fatalf("first call to Dial(%v) failed: %v", testAddress, err)
+		t.Fatalf("first call to Dial failed: %v", err)
 	}
 	if conn1 == nil {
-		t.Fatalf("first call to Dial(%v)=(nil, _), want not nil", testAddress)
+		t.Fatal("first call to Dial(_)=(nil, _), want not nil")
 	}
-	if got, want := hsConnMap[testAddress], conn1; got != want {
-		t.Fatalf("hsConnmap[%v] = %v, want %v", testAddress, got, want)
+	if got, want := hsConn, conn1; got != want {
+		t.Fatalf("hsConn=%v, want %v", got, want)
 	}
 
 	// Second call to Dial should return conn1 above.
 	conn2, err := Dial(testAddress)
 	if err != nil {
-		t.Fatalf("second call to Dial(%v) failed: %v", testAddress, err)
+		t.Fatalf("second call to Dial(_) failed: %v", err)
 	}
 	if got, want := conn2, conn1; got != want {
-		t.Fatalf("second call to Dial(%v)=(%v, _), want (%v, _)", testAddress, got, want)
-	}
-	if got, want := hsConnMap[testAddress], conn1; got != want {
-		t.Fatalf("hsConnMap[%v] = %v, want %v", testAddress, got, want)
-	}
-
-	// Third call to Dial using a different address should create a new
-	// connection.
-	conn3, err := Dial(testAddress2)
-	if err != nil {
-		t.Fatalf("third call to Dial(%v) failed: %v", testAddress2, err)
-	}
-	if conn3 == nil {
-		t.Fatalf("third call to Dial(%v)=(nil, _), want not nil", testAddress)
-	}
-	if got, want := hsConnMap[testAddress2], conn3; got != want {
-		t.Fatalf("hsConnmap[%v] = %v, want %v", testAddress2, got, want)
+		t.Fatalf("second call to Dial(_)=(%v, _), want (%v,. _)", got, want)
 	}
-	if got, want := conn2 == conn3, false; got != want {
-		t.Fatalf("(conn2 == conn3) = %v, want %v", got, want)
+	if got, want := hsConn, conn1; got != want {
+		t.Fatalf("hsConn=%v, want %v", got, want)
 	}
 }