Update dns-proxy flag name

Also remove `MaxUpstreamConnsFlag` const as it's no longer referenced in more than one place and to make things more consistent with how the other flags are referenced.

cmd/cloudflared/tunnel/cmd.go

@@ -1004,7 +1004,7 @@ func configureProxyDNSFlags(shouldHide bool) []cli.Flag {
 			Hidden:  shouldHide,
 		}),
 		altsrc.NewIntFlag(&cli.IntFlag{
-			Name:    tunneldns.MaxUpstreamConnsFlag,
+			Name:    "proxy-dns-max-upstream-conns",
 			Usage:   "Maximum concurrent connections to upstream. Setting to 0 means unlimited.",
 			Value:   tunneldns.MaxUpstreamConnsDefault,
 			Hidden:  shouldHide,

cmd/cloudflared/tunnel/server.go

@@ -15,9 +15,9 @@ func runDNSProxyServer(c *cli.Context, dnsReadySignal, shutdownC chan struct{},
 	if port <= 0 || port > 65535 {
 		return errors.New("The 'proxy-dns-port' must be a valid port number in <1, 65535> range.")
 	}
-	maxUpstreamConnections := c.Int(tunneldns.MaxUpstreamConnsFlag)
+	maxUpstreamConnections := c.Int("proxy-dns-max-upstream-conns")
 	if maxUpstreamConnections < 0 {
-		return fmt.Errorf("'%s' must be 0 or higher", tunneldns.MaxUpstreamConnsFlag)
+		return fmt.Errorf("'%s' must be 0 or higher", "proxy-dns-max-upstream-conns")
 	}
 	listener, err := tunneldns.CreateListener(c.String("proxy-dns-address"), uint16(port), c.StringSlice("proxy-dns-upstream"), c.StringSlice("proxy-dns-bootstrap"), maxUpstreamConnections, log)
 	if err != nil {

tunneldns/tunnel.go

@@ -23,7 +23,6 @@ import (
 const (
 	LogFieldAddress         = "address"
 	LogFieldURL             = "url"
-	MaxUpstreamConnsFlag    = "max-upstream-conns"
 	MaxUpstreamConnsDefault = 5
 )
 
@@ -71,7 +70,7 @@ func Command(hidden bool) *cli.Command {
 				EnvVars: []string{"TUNNEL_DNS_BOOTSTRAP"},
 			},
 			&cli.IntFlag{
-				Name:    MaxUpstreamConnsFlag,
+				Name:    "max-upstream-conns",
 				Usage:   "Maximum concurrent connections to upstream. Setting to 0 means unlimited.",
 				Value:   MaxUpstreamConnsDefault,
 				EnvVars: []string{"TUNNEL_DNS_MAX_UPSTREAM_CONNS"},
@@ -98,7 +97,7 @@ func Run(c *cli.Context) error {
 		uint16(c.Uint("port")),
 		c.StringSlice("upstream"),
 		c.StringSlice("bootstrap"),
-		c.Int(MaxUpstreamConnsFlag),
+		c.Int("max-upstream-conns"),
 		log,
 	)