Add --interface flag for choosing which network interface to listen on (

#81) * Add --interface flag * Fix default networkInterface
bradleyjkemp · Mar 3, 2020 · 2efa4b2 · 2efa4b2
1 parent eff327c
commit 2efa4b2
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Showing 3 changed files with 16 additions and 10 deletions.
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -1,7 +1,8 @@
 # Changelog
 
-## Unreleased changes
+## [v0.2.5](https:/bradleyjkemp/grpc-tools/releases/tag/v0.2.5)
 * Added grpc-proxy options `WithServerOptions` and `WithDialOptions`, deprecated `WithOptions` [#71](https:/bradleyjkemp/grpc-tools/pull/71).
+* Added a new command-line option, `--interface` to allow choosing which network interface `grpc-proxy` listens on [#81](https:/bradleyjkemp/grpc-tools/pull/81).
 
 ## [v0.2.4](https:/bradleyjkemp/grpc-tools/releases/tag/v0.2.4)
 * Added a new command-line option, `--tls_secrets_file`, to write the [TLS master secrets file](https://developer.mozilla.org/en-US/docs/Mozilla/Projects/NSS/Key_Log_Format) to the specified path. This can be used later with different application, such as Wireshark, to decrypt the gRPC traffic [#63](https:/bradleyjkemp/grpc-tools/pull/63).

diff --git a/grpc-proxy/config.go b/grpc-proxy/config.go
@@ -73,6 +73,7 @@ func WithDialer(dialer ContextDialer) Configurator {
 }
 
 var (
+ fNetworkInterface string
  fPort int
  fCertFile string
  fKeyFile string
@@ -84,6 +85,7 @@ var (
 
 // Must be called before flag.Parse() if using the DefaultFlags option
 func RegisterDefaultFlags() {
+ flag.StringVar(&fNetworkInterface, "interface", "localhost", "Network interface to listen on. By default listens on the localhost interface.")
  flag.IntVar(&fPort, "port", 0, "Port to listen on.")
  flag.StringVar(&fCertFile, "cert", "", "Certificate file to use for serving using TLS. By default the current directory will be scanned for mkcert certificates to use.")
  flag.StringVar(&fKeyFile, "key", "", "Key file to use for serving using TLS. By default the current directory will be scanned for mkcert keys to use.")
@@ -96,6 +98,7 @@ func RegisterDefaultFlags() {
 // This must be used after a call to flag.Parse()
 func DefaultFlags() Configurator {
  return func(s *server) {
+ s.networkInterface = fNetworkInterface
  s.port = fPort
  s.certFile = fCertFile
  s.keyFile = fKeyFile

diff --git a/grpc-proxy/proxy.go b/grpc-proxy/proxy.go
@@ -32,11 +32,12 @@ type server struct {
  grpcServer *grpc.Server
  logger logrus.FieldLogger
 
- port int
- certFile string
- keyFile string
- x509Cert *x509.Certificate
- tlsCert tls.Certificate
+ networkInterface string
+ port int
+ certFile string
+ keyFile string
+ x509Cert *x509.Certificate
+ tlsCert tls.Certificate
 
  destination string
  connPool *internal.ConnPool
@@ -53,8 +54,9 @@ type server struct {
 func New(configurators ...Configurator) (*server, error) {
  logger := logrus.New()
  s := &server{
- logger: logger,
- dialer: proxydialer.NewProxyDialer(httpproxy.FromEnvironment().ProxyFunc()),
+ logger: logger,
+ dialer: proxydialer.NewProxyDialer(httpproxy.FromEnvironment().ProxyFunc()),
+ networkInterface: "localhost", // default to just localhost if no other interface is chosen
  }
  s.serverOptions = []grpc.ServerOption{
  grpc.CustomCodec(codec.NoopCodec{}), // Allows for passing raw []byte messages around
@@ -103,9 +105,9 @@ func New(configurators ...Configurator) (*server, error) {
 
 func (s *server) Start() error {
  var err error
- s.listener, err = net.Listen("tcp", fmt.Sprintf("localhost:%d", s.port))
+ s.listener, err = net.Listen("tcp", fmt.Sprintf("%s:%d", s.networkInterface, s.port))
  if err != nil {
- return fmt.Errorf("failed to listen on port (%d): %v", s.port, err)
+ return fmt.Errorf("failed to listen on interface (%s:%d): %v", s.networkInterface, s.port, err)
  }
  s.logger.Infof("Listening on %s", s.listener.Addr())
  if s.x509Cert != nil {