cmd/awwan: implement socket based activation on serve command

The "awwan serve" command now can run based on socket activation under
systemd.

4 files changed, 33 insertions, 11 deletions

diff --git a/awwan.go b/awwan.go
index 06d59bf..82142aa 100644
--- a/awwan.go
+++ b/awwan.go
@@ -7,6 +7,7 @@ import (
 	"context"
 	"fmt"
 	"log"
+	"net"
 	"os"
 	"path/filepath"
 	"strconv"
@@ -483,14 +484,14 @@ out:
 }
 
 // Serve start the web-user interface that serve awwan through HTTP.
-func (aww *Awwan) Serve(address string, isDev bool) (err error) {
+func (aww *Awwan) Serve(listener net.Listener, address string, isDev bool) (err error) {
 	var logp = `Serve`
 
 	if isDev {
 		go internal.Watch()
 	}
 
-	aww.httpd, err = newHTTPServer(aww, address)
+	aww.httpd, err = newHTTPServer(aww, listener, address)
 	if err != nil {
 		return fmt.Errorf(`%s: %w`, logp, err)
 	}
diff --git a/cmd/awwan/main.go b/cmd/awwan/main.go
index 39df4cb..5411515 100644
--- a/cmd/awwan/main.go
+++ b/cmd/awwan/main.go
@@ -10,10 +10,12 @@ import (
 	"flag"
 	"fmt"
 	"log"
+	"net"
 	"os"
 	"strings"
 
 	"git.sr.ht/~shulhan/awwan"
+	"git.sr.ht/~shulhan/pakakeh.go/lib/systemd"
 )
 
 const (
@@ -254,7 +256,24 @@ func main() {
 	case awwan.CommandModePlay:
 		err = aww.Play(ctx, req)
 	case awwan.CommandModeServe:
-		err = aww.Serve(*serveAddress, *isDev)
+		var listeners []net.Listener
+		listeners, err = systemd.Listeners(true)
+		if err != nil {
+			log.Fatal(err)
+		}
+		if len(listeners) > 1 {
+			log.Fatal(`too many listeners received for activation`)
+		}
+		var listener net.Listener
+		if len(listeners) == 1 {
+			listener = listeners[0]
+			gotAddr := listener.Addr().String()
+			if gotAddr != *serveAddress {
+				log.Fatalf(`invalid Listener address, got %s, want %s`,
+					gotAddr, *serveAddress)
+			}
+		}
+		err = aww.Serve(listener, *serveAddress, *isDev)
 	}
 	if err != nil {
 		log.Fatalf(`%s: %s`, logp, err)
diff --git a/http_server.go b/http_server.go
index df30db0..2a7f534 100644
--- a/http_server.go
+++ b/http_server.go
@@ -11,6 +11,7 @@ import (
 	"fmt"
 	"io/fs"
 	"log"
+	"net"
 	"net/http"
 	"os"
 	"path"
@@ -62,7 +63,7 @@ type httpServer struct {
 
 // newHTTPServer create and initialize HTTP server to serve awwan HTTP API
 // and web user interface.
-func newHTTPServer(aww *Awwan, address string) (httpd *httpServer, err error) {
+func newHTTPServer(aww *Awwan, listener net.Listener, address string) (httpd *httpServer, err error) {
 	var (
 		logp = `newHTTPServer`
 	)
@@ -92,8 +93,9 @@ func newHTTPServer(aww *Awwan, address string) (httpd *httpServer, err error) {
 	}
 
 	var serverOpts = libhttp.ServerOptions{
-		Memfs:   internal.MemfsWui,
-		Address: address,
+		Listener: listener,
+		Memfs:    internal.MemfsWui,
+		Address:  address,
 	}
 
 	httpd.Server, err = libhttp.NewServer(serverOpts)
diff --git a/http_server_test.go b/http_server_test.go
index 8617c65..f6a32aa 100644
--- a/http_server_test.go
+++ b/http_server_test.go
@@ -49,7 +49,7 @@ func TestHttpServer_Decrypt(t *testing.T) {
 
 	var httpd *httpServer
 
-	httpd, err = newHTTPServer(aww, ``)
+	httpd, err = newHTTPServer(aww, nil, ``)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -133,7 +133,7 @@ func TestHttpServer_Encrypt(t *testing.T) {
 
 	var httpd *httpServer
 
-	httpd, err = newHTTPServer(aww, ``)
+	httpd, err = newHTTPServer(aww, nil, ``)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -217,7 +217,7 @@ func TestHttpServer_Execute(t *testing.T) {
 	)
 
 	go func() {
-		err = aww.Serve(address, isDev)
+		err = aww.Serve(nil, address, isDev)
 		if err != nil {
 			log.Fatal(err)
 		}
@@ -348,7 +348,7 @@ func TestHttpServer_ExecuteCancel(t *testing.T) {
 	)
 
 	go func() {
-		err = aww.Serve(address, isDev)
+		err = aww.Serve(nil, address, isDev)
 		if err != nil {
 			log.Fatal(err)
 		}
@@ -497,7 +497,7 @@ func TestHttpServer_FSGet(t *testing.T) {
 
 	var httpd *httpServer
 
-	httpd, err = newHTTPServer(aww, ``)
+	httpd, err = newHTTPServer(aww, nil, ``)
 	if err != nil {
 		t.Fatal(err)
 	}