metis: implement gRPC daemon server

metis/cmd/daemon.go

@@ -17,12 +17,15 @@ limitations under the License.
 package main
 
 import (
+	"context"
 	"os"
+	"os/signal"
+	"syscall"
 
 	"github.com/spf13/cobra"
 	cliflag "k8s.io/component-base/cli/flag"
 	"k8s.io/klog/v2"
-	"k8s.io/metis/daemon"
+	"k8s.io/metis/pkg/daemon"
 )
 
 func newDaemonCommand() *cobra.Command {
@@ -42,7 +45,11 @@ func newDaemonCommand() *cobra.Command {
 			var cfg daemon.Config
 			_ = opts.ApplyTo(&cfg)
 			d := daemon.NewDaemon(cfg)
-			if err := d.Run(); err != nil {
+
+			ctx, stop := signal.NotifyContext(context.Background(), os.Interrupt, syscall.SIGTERM)
+			defer stop()
+
+			if err := d.Run(ctx); err != nil {
 				klog.ErrorS(err, "Daemon failed to run")
 				os.Exit(1)
 			}

metis/cmd/daemonoptions.go

@@ -20,7 +20,8 @@ import (
 	"time"
 
 	cliflag "k8s.io/component-base/cli/flag"
-	"k8s.io/metis/daemon"
+	"k8s.io/metis/pkg"
+	"k8s.io/metis/pkg/daemon"
 )
 
 // DaemonOptions holds the metis daemon options.
@@ -36,9 +37,10 @@ func (o *DaemonOptions) AddFlags() cliflag.NamedFlagSets {
 	}
 
 	fs := fss.FlagSet("daemon")
-	// We apply default values directly within Flags for now, or assume they are pre-initialized
 	fs.DurationVar(&o.MonitorInterval, "monitor-interval", 5*time.Second, "Monitor interval (e.g., 5s, 1m)")
 	fs.DurationVar(&o.ReleaseCooldown, "release-cooldown", 1*time.Minute, "Release cooldown duration (e.g., 5m)")
+	fs.StringVar(&o.DBPath, "db-path", pkg.DefaultDBPath, "Path to the SQLite database file")
+	fs.StringVar(&o.SocketPath, "socket-path", pkg.DefaultSockPath, "Path to the Unix domain socket")
 
 	return fss
 }
@@ -51,6 +53,8 @@ func (o *DaemonOptions) ApplyTo(cfg *daemon.Config) error {
 
 	cfg.MonitorInterval = o.MonitorInterval
 	cfg.ReleaseCooldown = o.ReleaseCooldown
+	cfg.DBPath = o.DBPath
+	cfg.SocketPath = o.SocketPath
 
 	return nil
 }

metis/go.mod

@@ -11,6 +11,7 @@ require (
 	github.com/spf13/pflag v1.0.10
 	google.golang.org/grpc v1.72.2
 	google.golang.org/protobuf v1.36.8
+	k8s.io/apimachinery v0.35.1
 	k8s.io/component-base v0.35.1
 	k8s.io/klog/v2 v2.140.0
 )
@@ -42,7 +43,6 @@ require (
 	golang.org/x/text v0.34.0 // indirect
 	google.golang.org/genproto/googleapis/rpc v0.0.0-20250528174236-200df99c418a // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect
-	k8s.io/apimachinery v0.35.1 // indirect
 	k8s.io/kube-openapi v0.0.0-20250910181357-589584f1c912 // indirect
 	k8s.io/utils v0.0.0-20251002143259-bc988d571ff4 // indirect
 	sigs.k8s.io/json v0.0.0-20250730193827-2d320260d730 // indirect