ipn/localapi, cli, clientmetric: add ipnbus feature tag; fix omit.go stub

Add a new "ipnbus" build feature tag so the watch-ipn-bus LocalAPI
endpoint can be independently controlled, rather than being gated
behind HasDebug || HasServe. Minimal/embedded builds that omit both
debug and serve were getting 404s on watch-ipn-bus, breaking
"tailscale up --authkey=..." and other CLI flows that depend on
WatchIPNBus.

In the CLI, check buildfeatures.HasIPNBus before attempting to watch
the IPN bus in "tailscale up"/"tailscale login", and exit early with
an informational message when the feature is omitted.

Also add the missing NewCounterFunc stub to clientmetric/omit.go,
which caused compilation errors when building with
ts_omit_clientmetrics and netstack enabled.

Fixes #19240

Change-Id: I2e3c69a72fc50fa02542b91b8a54859618a463d1
Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
This commit is contained in:
Brad Fitzpatrick
2026-04-07 14:48:57 +00:00
committed by Brad Fitzpatrick
parent 9a7f143903
commit 1b5b43787c
6 changed files with 37 additions and 4 deletions
@@ -0,0 +1,13 @@
// Copyright (c) Tailscale Inc & contributors
// SPDX-License-Identifier: BSD-3-Clause
// Code generated by gen.go; DO NOT EDIT.
//go:build ts_omit_ipnbus
package buildfeatures
// HasIPNBus is whether the binary was built with support for modular feature "IPN notification bus (watch-ipn-bus) support, used by GUIs, debugging, and nicer 'tailscale up' support".
// Specifically, it's whether the binary was NOT built with the "ts_omit_ipnbus" build tag.
// It's a const so it can be used for dead code elimination.
const HasIPNBus = false
@@ -0,0 +1,13 @@
// Copyright (c) Tailscale Inc & contributors
// SPDX-License-Identifier: BSD-3-Clause
// Code generated by gen.go; DO NOT EDIT.
//go:build !ts_omit_ipnbus
package buildfeatures
// HasIPNBus is whether the binary was built with support for modular feature "IPN notification bus (watch-ipn-bus) support, used by GUIs, debugging, and nicer 'tailscale up' support".
// Specifically, it's whether the binary was NOT built with the "ts_omit_ipnbus" build tag.
// It's a const so it can be used for dead code elimination.
const HasIPNBus = true