Support dynamically updating Softnet policy (#477)

* Support dynamically updating Softnet policy

* Use cmpopts.EquateEmpty() when comparing two VMSpecs

pkg/resource/v1/cmp_test.go

@@ -5,6 +5,7 @@ import (
 
 	v1 "github.com/cirruslabs/orchard/pkg/resource/v1"
 	"github.com/google/go-cmp/cmp"
+	"github.com/stretchr/testify/require"
 )
 
 // TestVM ensures that v1.VM and its embedded structs can be compared
@@ -12,3 +13,12 @@ import (
 func TestVM(t *testing.T) {
 	cmp.Equal(v1.VM{}, v1.VM{})
 }
+
+func TestVMSpecSemanticallyEqualEquatesEmptySlices(t *testing.T) {
+	nilSlicesSpec := v1.VMSpec{}
+	emptySlicesSpec := v1.VMSpec{
+		NetSoftnetAllow: []string{},
+		NetSoftnetBlock: []string{},
+	}
+	require.True(t, nilSlicesSpec.SemanticallyEqual(emptySlicesSpec))
+}

pkg/resource/v1/v1.go

@@ -3,7 +3,11 @@ package v1
 import (
 	"encoding/json"
 	"fmt"
+	"slices"
 	"time"
+
+	"github.com/google/go-cmp/cmp"
+	"github.com/google/go-cmp/cmp/cmpopts"
 )
 
 // Meta is a common set of fields that apply to all resources managed by the Controller.
@@ -193,6 +197,21 @@ type VMSpec struct {
 	PowerState           PowerState `json:"powerState,omitempty"`
 }
 
+func (vm VMSpec) SemanticallyEqual(other VMSpec) bool {
+	// Treat omitted and explicitly empty collections as the same VM specification
+	return cmp.Equal(vm, other, cmpopts.EquateEmpty())
+}
+
+func (vm VMSpec) SoftnetEnabled() bool {
+	return vm.NetSoftnetDeprecated || vm.NetSoftnet ||
+		len(vm.NetSoftnetAllow) != 0 || len(vm.NetSoftnetBlock) != 0
+}
+
+func (vm VMSpec) SoftnetPolicyChanged(other VMSpec) bool {
+	return !slices.Equal(vm.NetSoftnetAllow, other.NetSoftnetAllow) ||
+		!slices.Equal(vm.NetSoftnetBlock, other.NetSoftnetBlock)
+}
+
 type VMSpecReadOnly struct {
 	LocalName string `json:"localName,omitempty"`