composer: split out the local worker socket

Everybody hates the local workers. The first step of getting rid of them
is to split their socket out of osbuild-composer.socket - we need to keep
this one to support the Weldr API but the local worker socket can live in
its own file.

The behaviour should be the same for now: osbuild-composer.service always
starts the local worker socket.

However, this split allows the osbuild-composer executable to be run without
the Weldr API activated. The following commit explores this option more
in depth.

Note that the new socket can be used by root only because workers are always
run as root.

Signed-off-by: Ondřej Budai <ondrej@budai.cz>

cmd/osbuild-composer/composer.go

@@ -79,7 +79,7 @@ func NewComposer(config *ComposerConfigFile, stateDir, cacheDir string, logger *
 	return &c, nil
 }
 
-func (c *Composer) InitWeldr(repoPaths []string, weldrListener, localWorkerListener net.Listener) error {
+func (c *Composer) InitWeldr(repoPaths []string, weldrListener net.Listener) error {
 	archName := common.CurrentArch()
 
 	hostDistro, beta, err := c.distros.FromHost()
@@ -109,7 +109,6 @@ func (c *Composer) InitWeldr(repoPaths []string, weldrListener, localWorkerListe
 	c.weldr = weldr.New(c.rpm, arch, hostDistro, repos[archName], c.logger, store, c.workers, compatOutputDir)
 
 	c.weldrListener = weldrListener
-	c.localWorkerListener = localWorkerListener
 
 	return nil
 }
@@ -133,6 +132,10 @@ func (c *Composer) InitAPI(cert, key string, l net.Listener) error {
 	return nil
 }
 
+func (c *Composer) InitLocalWorker(l net.Listener) {
+	c.localWorkerListener = l
+}
+
 func (c *Composer) InitRemoteWorkers(cert, key string, l net.Listener) error {
 	tlsConfig, err := createTLSConfig(&connectionConfig{
 		CACertFile:     c.config.Worker.CA,
@@ -153,10 +156,6 @@ func (c *Composer) InitRemoteWorkers(cert, key string, l net.Listener) error {
 //
 // Running without the weldr API is currently not supported.
 func (c *Composer) Start() error {
-	if c.weldr == nil {
-		return errors.New("weldr was not initialized")
-	}
-
 	if c.localWorkerListener != nil {
 		go func() {
 			err := c.workers.Serve(c.localWorkerListener)
@@ -200,7 +199,17 @@ func (c *Composer) Start() error {
 		}()
 	}
 
-	return c.weldr.Serve(c.weldrListener)
+	if c.weldrListener != nil {
+		go func() {
+			err := c.weldr.Serve(c.weldrListener)
+			if err != nil {
+				panic(err)
+			}
+		}()
+	}
+
+	// wait indefinitely
+	select {}
 }
 
 func (c *Composer) ensureStateDirectory(name string, perm os.FileMode) (string, error) {

cmd/osbuild-composer/main.go

@@ -65,16 +65,22 @@ func main() {
 	}
 
 	if l, exists := listeners["osbuild-composer.socket"]; exists {
-		if len(l) != 2 {
+		if len(l) != 1 {
-			log.Fatalf("Expected two listeners in osbuild-composer.socket, but found %d", len(l))
+			log.Fatal("The osbuild-composer.socket unit is misconfigured. It should contain only one socket.")
 		}
 
-		err = composer.InitWeldr(repositoryConfigs, l[0], l[1])
+		err = composer.InitWeldr(repositoryConfigs, l[0])
 		if err != nil {
 			log.Fatalf("Error initializing weldr API: %v", err)
 		}
-	} else {
+	}
-		log.Fatalf("osbuild-composer.socket doesn't exist")
+
+	if l, exists := listeners["osbuild-local-worker.socket"]; exists {
+		if len(l) != 1 {
+			log.Fatal("The osbuild-local-worker.socket unit is misconfigured. It should contain only one socket.")
+		}
+
+		composer.InitLocalWorker(l[0])
 	}
 
 	if l, exists := listeners["osbuild-composer-api.socket"]; exists {

distribution/osbuild-composer.socket

@@ -3,7 +3,6 @@ Description=OSBuild Composer Weldr API socket
 
 [Socket]
 ListenStream=/run/weldr/api.socket
-ListenStream=/run/osbuild-composer/job.socket
 SocketGroup=weldr
 SocketMode=660
 

distribution/osbuild-local-worker.socket

@@ -0,0 +1,9 @@
+[Unit]
+Description=OSBuild local worker API socket
+
+[Socket]
+Service=osbuild-composer.service
+ListenStream=/run/osbuild-composer/job.socket
+
+[Install]
+WantedBy=sockets.target

distribution/osbuild-worker@.service

@@ -1,7 +1,7 @@
 [Unit]
 Description=OSBuild Composer Worker (%i)
-Requires=osbuild-composer.socket
+Requires=osbuild-local-worker.socket
-After=multi-user.target osbuild-composer.socket
+After=multi-user.target osbuild-local-worker.socket
 
 [Service]
 Type=simple

osbuild-composer.spec

@@ -245,6 +245,7 @@ cd $PWD/_build/src/%{goipath}
 %{_unitdir}/osbuild-composer.service
 %{_unitdir}/osbuild-composer.socket
 %{_unitdir}/osbuild-composer-api.socket
+%{_unitdir}/osbuild-local-worker.socket
 %{_unitdir}/osbuild-remote-worker.socket
 %{_sysusersdir}/osbuild-composer.conf