implement periodic checks in a function

chord/httpnode/server.go

@@ -1,7 +1,9 @@
 package httpnode
 
 import (
+	"context"
 	"errors"
+	"fmt"
 	"net"
 	"net/http"
 	"net/netip"
@@ -49,6 +51,20 @@ func (n *Node) Router() http.Handler {
 	return m
 }
 
+// Check performs checks that implement the Chord protocol.
+// It must be called periodically while the node is alive.
+func (n *Node) Check(ctx context.Context) error {
+	if err := chord.Stabilize(ctx, n.client, n.self); err != nil {
+		return fmt.Errorf("failed to stabilize: %w", err)
+	}
+	// TODO(zeph): enable once implemented
+	// if err := chord.FixFingers(ctx, n.client, n.self); err != nil {
+	// 	return fmt.Errorf("failed to fix fingers: %w", err)
+	// }
+	chord.CheckPredecessor(ctx, n.client, n.self)
+	return nil
+}
+
 func (n *Node) successor(w http.ResponseWriter, r *http.Request) {
 	s := r.FormValue("s")
 	id, err := chord.ParseID(s)