A common pattern in event bus usage is to run a goroutine to service a
collection of subscribers on a single bus client. To have an orderly shutdown,
however, we need a way to wait for such a goroutine to be finished.
This commit adds a Monitor type that makes this pattern easier to wire up:
rather than having to track all the subscribers and an extra channel, the
component need only track the client and the monitor. For example:
cli := bus.Client("example")
m := cli.Monitor(func(c *eventbus.Client) {
s1 := eventbus.Subscribe[T](cli)
s2 := eventbus.Subscribe[U](cli)
for {
select {
case <-c.Done():
return
case t := <-s1.Events():
processT(t)
case u := <-s2.Events():
processU(u)
}
}
})
To shut down the client and wait for the goroutine, the caller can write:
m.Close()
which closes cli and waits for the goroutine to finish. Or, separately:
cli.Close()
// do other stuff
m.Wait()
While the goroutine management is not explicitly tied to subscriptions, it is a
common enough pattern that this seems like a useful simplification in use.
Updates #15160
Change-Id: I657afda1cfaf03465a9dce1336e9fd518a968bca
Signed-off-by: M. J. Fromberger <fromberger@tailscale.com>
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.
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 1.23. (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:
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.
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