add systemd-socket activation

go.mod

@@ -5,6 +5,7 @@ go 1.21
 require (
 	entgo.io/ent v0.12.5
 	github.com/c2h5oh/datasize v0.0.0-20220606134207-859f65c6625b
+	github.com/coreos/go-systemd/v22 v22.5.0
 	github.com/go-chi/chi/v5 v5.0.10
 	github.com/go-chi/render v1.0.3
 	github.com/jackc/pgx/v4 v4.18.1

go.sum

@@ -21,6 +21,8 @@ github.com/coreos/go-systemd v0.0.0-20190321100706-95778dfbb74e/go.mod h1:F5haX7
 github.com/coreos/go-systemd v0.0.0-20190719114852-fd7a80b32e1f/go.mod h1:F5haX7vjVVG0kc13fIWeqUViNPyEJxv/OmvnBo0Yme4=
 github.com/coreos/go-systemd v0.0.0-20191104093116-d3cd4ed1dbcf h1:iW4rZ826su+pqaw19uhpSCzhj44qo35pNgKFGqzDKkU=
 github.com/coreos/go-systemd v0.0.0-20191104093116-d3cd4ed1dbcf/go.mod h1:F5haX7vjVVG0kc13fIWeqUViNPyEJxv/OmvnBo0Yme4=
+github.com/coreos/go-systemd/v22 v22.5.0 h1:RrqgGjYQKalulkV8NGVIfkXQf6YYmOyiJKk8iXXhfZs=
+github.com/coreos/go-systemd/v22 v22.5.0/go.mod h1:Y58oyj3AT4RCenI/lSvhwexgC+NSVTIJ3seZv2GcEnc=
 github.com/creack/pty v1.1.7/go.mod h1:lj5s0c3V2DBrqTV7llrYr5NG6My20zk30Fl46Y7DoTY=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
@@ -36,6 +38,7 @@ github.com/go-openapi/inflect v0.19.0/go.mod h1:lHpZVlpIQqLyKwJ4N+YSc9hchQy/i12f
 github.com/go-stack/stack v1.8.0/go.mod h1:v0f6uXyyMGvRgIKkXu+yp6POWl0qKG85gN/melR3HDY=
 github.com/go-test/deep v1.0.3 h1:ZrJSEWsXzPOxaZnFteGEfooLba+ju3FYIbOrS+rQd68=
 github.com/go-test/deep v1.0.3/go.mod h1:wGDj63lr65AM2AQyKZd/NYHGb0R+1RLqB8NKt3aSFNA=
+github.com/godbus/dbus/v5 v5.0.4/go.mod h1:xhWf0FNVPg57R7Z0UbKHbJfkEywrmjJnf7w5xrFpKfA=
 github.com/gofrs/uuid v4.0.0+incompatible h1:1SD/1F5pU8p29ybwgQSwpQk+mwdRrXCYuPhW6m+TnJw=
 github.com/gofrs/uuid v4.0.0+incompatible/go.mod h1:b2aQJv3Z4Fp6yNu3cdSllBxTCLRxnplIgP/c0N/04lM=
 github.com/google/go-cmp v0.6.0 h1:ofyhxvXcZhMsU5ulbFiLKl/XBFqE1GSq7atu8tAmTRI=

main.go

@@ -6,6 +6,7 @@ import (
 	"entgo.io/ent/dialect/sql"
 	"flag"
 	"fmt"
+	"github.com/coreos/go-systemd/v22/activation"
 	"github.com/go-chi/chi/v5"
 	"github.com/go-chi/chi/v5/middleware"
 	"github.com/go-chi/render"
@@ -98,6 +99,32 @@ func main() {
 
 	log.Info("Start listening...")
 	sockets := make([]net.Listener, 0)
+
+	// handle systemd socket activation
+	listeners, err := activation.Listeners()
+	if err != nil {
+		panic(err)
+	}
+
+	if len(listeners) > 0 {
+		for _, l := range listeners {
+			log.Infof("Listening on %s", l.Addr())
+			if err != nil {
+				log.Panicf("failure listing on socket %s: %v", l, err)
+			}
+			sockets = append(sockets, l)
+			l := l
+			go func() {
+				srv := &http.Server{
+					ReadTimeout:  time.Duration(conf.Httpd.Timeout.Read) * time.Second,
+					WriteTimeout: time.Duration(conf.Httpd.Timeout.Write) * time.Second,
+					IdleTimeout:  time.Duration(conf.Httpd.Timeout.Idle) * time.Second,
+					Handler:      r,
+				}
+				_ = srv.Serve(l)
+			}()
+		}
+	} else { // handle config if not systemd-socket activated
 		for _, l := range conf.Httpd.Listen {
 			if l.Socket != "" {
 				sL, err := net.Listen("unix", l.Socket)
@@ -139,6 +166,7 @@ func main() {
 				}(l)
 			}
 		}
+	}
 
 killLoop:
 	for {