Force use of "custom" network string for DialWithCustomDialer

dialer.go

@@ -34,15 +34,10 @@ func (df dialerFunctionWrapper) Call() (serverConn, string, error) {
 // value), and adding a new network type is as easy as writing the dialer
 // function and adding it to the map.
 func (w *Writer) getDialer() dialerFunctionWrapper {
-	if w.customDial != nil {
-		// we use 'customDialer' as the name, since the custom dialer can technically
-		// override any network we pass in anyways
-		return dialerFunctionWrapper{"customDialer", w.customDialer}
-	}
-
 	dialers := map[string]dialerFunctionWrapper{
 		"":        dialerFunctionWrapper{"unixDialer", w.unixDialer},
 		"tcp+tls": dialerFunctionWrapper{"tlsDialer", w.tlsDialer},
+		"custom":  dialerFunctionWrapper{"customDialer", w.customDialer},
 	}
 	dialer, ok := dialers[w.network]
 	if !ok {

dialer_test.go

@@ -47,6 +47,7 @@ func TestGetDialer(t *testing.T) {
 		t.Errorf("should get basicDialer, got: %v", dialer)
 	}
 
+	w.network = "custom"
 	w.customDial = func(string, string) (net.Conn, error) { return nil, nil }
 	dialer = w.getDialer()
 	if "customDialer" != dialer.Name {
@@ -209,10 +210,7 @@ func TestCustomDialer(t *testing.T) {
 	// A custom dialer can really be anything, so we don't test an actual connection
 	// instead we test the behavior of this code path
 
-	// a dialer implementation may still consult the passed network and address
-	// so make sure we don't change them before being passed in
-
-	nwork, addr := "custom_network_to_pass", "custom_addr_to_pass"
+	nwork, addr := "custom", "custom_addr_to_pass"
 	w := Writer{
 		priority: LOG_ERR,
 		tag:      "tag",

srslog.go

@@ -43,6 +43,7 @@ var ErrNilDialFunc = errors.New("srslog: nil DialFunc passed to DialWithCustomDi
 
 // DialWithCustomDialer establishes a connection by calling customDial.
 // Each write to the returned Writer sends a log message with the given facility, severity and tag.
+// Network must be "custom" in order for this package to use customDial.
 // While network and raddr will be passed to customDial, it is allowed for customDial to ignore them.
 // If customDial is nil, this function returns ErrNilDialFunc.
 func DialWithCustomDialer(network, raddr string, priority Priority, tag string, customDial DialFunc) (*Writer, error) {