These are pure-go implementations of some systemd-APIs for daemon-authors
(reference implementation is sd-daemon.h.
The idea is, to make it as simple as possible to write systemd-aware daemons.
Logging can happen to stderr, so the log-package is sufficient there for most
cases. systemd also provides APIs for socket activation,
startup notifications and a software watchdog), built on top of that.
We try to expose those features as simply (and idiomatically) as possible. For example, a socket activated http-server is as simple as
package main
import (
"github.com/Merovius/systemd"
"log"
"net"
"net/http"
)
func Handle(res http.ResponseWriter, req *http.Request) {
res.Write([]byte("Hello world"))
}
func main() {
var l net.Listener
n, err := systemd.GetPassedFiles(&l)
if n < 1 {
log.Fatal("Not enough sockets passed")
}
if err != nil {
log.Fatal(err)
}
http.HandleFunc("/", Handle)
err = http.Serve(l, nil)
log.Fatal(err)
}A watchdog-aware service is as simple as
package main
import (
"github.com/Merovius/systemd"
"log"
)
func main() {
wd, _, err := systemd.AutoWatchdog()
if err != nil {
log.Fatal(err)
}
// Do awesome stuff
}And the startup-notification protocol is handled as simple as
package main
import (
"github.com/Merovius/systemd"
)
func main() {
// Do initialization stuff
if err := systemd.NotifyReady(); err != nil {
log.Println(err)
}
}A while after I started working at this and a bit before I actually wanted to push it out, Brandon Philips announced a similar library. His and this library mainly share the socket-activation functionality. I'm currently evaluating whether it makes more sense to contribute to his library or maintain my own approach. This repository is only meant to enable this evaluation. Otherwise I would have polished the code as well as the API a little bit more before publishing. So please don't use this yet (and if you do, don't depend on it being actively maintained in the future or that the API does not change, IOW do it at your own risk).