add support for bind flag

Author: ezekg

cli/testdata/cmd_serve.test.txt

@@ -2,25 +2,23 @@
 exec relay add --file license.lic --key 9E32DD-D8CC22-771926-C2D834-C506DC-V3 --public-key e8601e48b69383ba520245fd07971e983d06d22c4257cfd82304601479cee788
 
 # set a port as environment variable
+env BIND=127.0.0.42
 env PORT=65007
 
 # start the server in the background with the environment variable
-exec relay serve --port $PORT &server_process&
+exec relay serve --bind $BIND --port $PORT &server_process_test&
 
 # wait for the server to start
 exec sleep 1
 
-# claim a license using the port from the environment variable
-exec curl -s -X PUT http://localhost:$PORT/v1/nodes/test_fingerprint
+# FIXME(ezekg) sh hack because testscript exits on interrupt i.e. a non-zero exit code
+# should be unreachable at default bind addr
+exec sh -c 'curl -sS -X PUT http://0.0.0.0:65007/v1/nodes/test_fingerprint || true'
+stderr 'Failed to connect to 0\.0\.0\.0 port 65007: Connection refused'
 
-# expect license data in the response
+# should be reachable at custom bind addr
+exec curl -s -X PUT http://$BIND:$PORT/v1/nodes/test_fingerprint
 stdout '"license_file":'
 
-# release the license
-exec curl -s -X DELETE http://localhost:$PORT/v1/nodes/test_fingerprint
-
-# expect no content in the response
-stdout ''
-
 # kill the process (stop the server)
-kill server_process
+kill server_process_test

internal/server/server.go

@@ -39,14 +39,14 @@ func (s *server) Run() error {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
-	address := fmt.Sprintf(":%d", s.config.ServerPort)
-	slog.Info("starting server", "port", s.config.ServerPort)
+	addr := fmt.Sprintf("%s:%d", s.config.ServerAddr, s.config.ServerPort)
+	slog.Info("starting server", "addr", s.config.ServerAddr, "port", s.config.ServerPort)
 
 	if s.Config().EnabledHeartbeat {
 		go s.reaper.Start(ctx)
 	}
 
-	if err := http.ListenAndServe(address, s.router); err != nil && !errors.Is(err, http.ErrServerClosed) {
+	if err := http.ListenAndServe(addr, s.router); err != nil && !errors.Is(err, http.ErrServerClosed) {
 		slog.Error("server failed to start", "error", err)
 
 		cancel()