Check for host validation before Create (#538)

* Check for host validation before Create

* feedback

topo/node/node.go

@@ -61,6 +61,8 @@ type Implementation interface {
 	// BackToBackLoop returns a bool if the node supports links directly between
 	// two ports on the same node.
 	BackToBackLoop() bool
+	// ValidateConstraints validates the host with the node's constraints.
+	ValidateConstraints() error
 }
 
 // Certer provides an interface for working with certs on nodes.
@@ -235,9 +237,6 @@ func ToResourceRequirements(kv map[string]string) corev1.ResourceRequirements {
 // Create will create the node in the k8s cluster with all services and config
 // maps.
 func (n *Impl) Create(ctx context.Context) error {
-	if err := n.ValidateConstraints(); err != nil {
-		return fmt.Errorf("node %s failed to validate node with errors: %s", n.Name(), err)
-	}
 	if err := n.CreatePod(ctx); err != nil {
 		return fmt.Errorf("node %s failed to create pod %w", n.Name(), err)
 	}

topo/topo.go

@@ -552,6 +552,12 @@ func (m *Manager) topologySpecs(ctx context.Context) ([]*topologyv1.Topology, er
 
 // push deploys the topology to the cluster.
 func (m *Manager) push(ctx context.Context) error {
+	for _, n := range m.nodes {
+		if err := n.ValidateConstraints(); err != nil {
+			return fmt.Errorf("failed to validate node %s: %w", n, err)
+		}
+	}
+
 	if _, err := m.kClient.CoreV1().Namespaces().Get(ctx, m.topo.Name, metav1.GetOptions{}); err != nil {
 		log.Infof("Creating namespace for topology: %q", m.topo.Name)
 		ns := &corev1.Namespace{

topo/topo_test.go

@@ -89,6 +89,13 @@ func (c *configurable) ConfigPush(_ context.Context, r io.Reader) error {
 	return nil
 }
 
+func (c *configurable) ValidateConstraints() error {
+	if len(c.Proto.HostConstraints) != 0 {
+		return fmt.Errorf("fake error for host constraints")
+	}
+	return nil
+}
+
 func NewConfigurable(impl *node.Impl) (node.Node, error) {
 	return &configurable{Impl: impl}, nil
 }
@@ -588,6 +595,23 @@ func TestCreate(t *testing.T) {
 				},
 			},
 		},
+	}, {
+		desc: "failed node validation",
+		topo: &tpb.Topology{
+			Name: "test",
+			Nodes: []*tpb.Node{{
+				Name:   "r1",
+				Vendor: tpb.Vendor(1002),
+				Services: map[uint32]*tpb.Service{
+					1000: {
+						Name: "ssh",
+					},
+				},
+				Config:          &tpb.Config{},
+				HostConstraints: []*tpb.HostConstraint{{Constraint: &tpb.HostConstraint_KernelConstraint{}}},
+			}},
+		},
+		wantErr: "failed to validate node",
 	}}
 	for _, tt := range tests {
 		t.Run(tt.desc, func(t *testing.T) {