James Tucker 4eec4423b4 util/eventbus: move Publisher publisher-interface impl to a non-generic core
Mirrors the same refactor previously applied to SubscriberFunc:

  - Publisher[T]: a thin user-facing facade. Holds a pointer to a
    non-generic publisherCore and exposes Publish/Close/ShouldPublish.
  - publisherCore: a non-generic struct that owns the *Client back-
    pointer, stop flag, and cached reflect.Type. It implements the
    package-private publisher interface (publishType, Close).
    The bus's per-Client publisher set is set.Set[publisher] keyed
    on this single non-generic type.

The publisher interface only exists to support diagnostic
introspection (Debugger.PublishTypes returning the list of types a
client publishes). Previously, satisfying that diagnostic-only
interface forced *Publisher[T] to be the implementor and cost a
per-T itab, generic dictionary, and equality function on every
event type ever passed through Publish[T]. Moving the
implementation to a non-generic core lets the diagnostic surface
work unchanged while charging zero per-T cost for the
diagnostic-driven generic interface.

Publisher[T].Publish is also slimmed: the channel/select/stopFlag
loop is now a non-generic publish() helper that takes the value as
'any'. The per-T body is reduced to forwarding the boxed value to
the helper.

Measured impact (util/eventbus/sizetest):

  total per-flow binary cost:
    linux/amd64:  2252.8 B/flow -> 1900.5 B/flow  (-352.3 B / -15.6%)
    linux/arm64:  2228.2 B/flow -> 1835.0 B/flow  (-393.2 B / -17.6%)

  Publisher per-receiver attribution:
    linux/amd64:   635.2 B/flow ->  369.6 B/flow  (-265.6 B / -41.8%)
    linux/arm64:   751.7 B/flow ->  373.2 B/flow  (-378.5 B / -50.4%)

Cumulative reduction from the original baseline (5167ff412):
    linux/amd64:  3096.6 B/flow -> 1900.5 B/flow  (-1196.1 B / -38.6%)
    linux/arm64:  3145.7 B/flow -> 1835.0 B/flow  (-1310.7 B / -41.7%)

Dropped per-T symbols (200-flow eventbus binary):

  - .dict.Publisher[T]                   was 14,400 B (72 B/T)
  - type:.eq.Publisher[T]                was 11,832 B (58 B/T)
  - go:itab.*Publisher[T],publisher      was  8,000 B (40 B/T)
  - (*Publisher[T]).Close shape stencils collapsed to 1

Behavior is unchanged: BenchmarkBasicThroughput is within noise
(2018 -> 2038 ns/op at -benchtime=2s) and all eventbus tests pass.

Updates #12614

Change-Id: I61979c2bf95d2a711c2321e6e0b4b7d15980e9f5
Signed-off-by: James Tucker <james@tailscale.com>
2026-05-11 14:39:42 -07:00
2026-05-04 10:34:27 -07:00
2026-03-27 08:41:33 +00:00
2026-01-27 16:15:17 -08:00
2026-05-07 15:33:05 -07:00

Tailscale

https://tailscale.com

Private WireGuard® networks made easy

Overview

This repository contains the majority of Tailscale's open source code. Notably, it includes the tailscaled daemon and the tailscale CLI tool. The tailscaled daemon runs on Linux, Windows, macOS, and to varying degrees on FreeBSD and OpenBSD. The Tailscale iOS and Android apps use this repo's code, but this repo doesn't contain the mobile GUI code.

Other Tailscale repos of note:

For background on which parts of Tailscale are open source and why, see https://tailscale.com/opensource/.

Using

We serve packages for a variety of distros and platforms at https://pkgs.tailscale.com.

Other clients

The macOS, iOS, and Windows clients use the code in this repository but additionally include small GUI wrappers. The GUI wrappers on non-open source platforms are themselves not open source.

Building

We always require the latest Go release, currently Go 1.26. (While we build releases with our Go fork, its use is not required.)

go install tailscale.com/cmd/tailscale{,d}

If you're packaging Tailscale for distribution, use build_dist.sh instead, to burn commit IDs and version info into the binaries:

./build_dist.sh tailscale.com/cmd/tailscale
./build_dist.sh tailscale.com/cmd/tailscaled

If your distro has conventions that preclude the use of build_dist.sh, please do the equivalent of what it does in your distro's way, so that bug reports contain useful version information.

Bugs

Please file any issues about this code or the hosted service on the issue tracker.

Contributing

PRs welcome! But please file bugs. Commit messages should reference bugs.

We require Developer Certificate of Origin Signed-off-by lines in commits.

See commit-messages.md (or skim git log) for our commit message style.

About Us

Tailscale is primarily developed by the people at https://github.com/orgs/tailscale/people. For other contributors, see:

WireGuard is a registered trademark of Jason A. Donenfeld.

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