Simplify state reconciliation and support changing Softnet settings (#364)

* Simplify state reconciliation and support changing Softnet settings

* Remove unused "updateFunc" parameter from syncOnDiskVMs()

* Don't take an address of a loop variable

* ensure → ensures

* updateVMState(): don't forget to update VMState

* Introduce TestSpecUpdateSoftnet integration test

* Update OpenAPI specification to include generation/observedGeneration

internal/tests/spec_update_test.go

@@ -0,0 +1,140 @@
+package tests
+
+import (
+	"context"
+	"fmt"
+	"testing"
+	"time"
+
+	"github.com/cirruslabs/orchard/internal/imageconstant"
+	"github.com/cirruslabs/orchard/internal/tests/devcontroller"
+	"github.com/cirruslabs/orchard/internal/tests/wait"
+	"github.com/cirruslabs/orchard/internal/worker/ondiskname"
+	v1 "github.com/cirruslabs/orchard/pkg/resource/v1"
+	"github.com/samber/lo"
+	"github.com/shirou/gopsutil/v4/process"
+	"github.com/stretchr/testify/require"
+)
+
+func TestSpecUpdateSoftnet(t *testing.T) {
+	devClient, _, _ := devcontroller.StartIntegrationTestEnvironment(t)
+
+	// Create a VM
+	vmName := "test"
+
+	err := devClient.VMs().Create(t.Context(), &v1.VM{
+		Meta: v1.Meta{
+			Name: vmName,
+		},
+		Image:    imageconstant.DefaultMacosImage,
+		CPU:      4,
+		Memory:   8 * 1024,
+		Headless: true,
+		Status:   v1.VMStatusPending,
+	})
+	require.NoError(t, err)
+
+	// Wait for the VM to start
+	var vm *v1.VM
+
+	require.True(t, wait.Wait(2*time.Minute, func() bool {
+		vm, err = devClient.VMs().Get(context.Background(), vmName)
+		require.NoError(t, err)
+
+		t.Logf("Waiting for the VM to start. Current status: %s", vm.Status)
+
+		return vm.Status == v1.VMStatusRunning
+	}), "failed to start a VM")
+
+	// Ensure that Softnet is not enabled for a VM
+	tartVMName := ondiskname.New(vmName, vm.UID, vm.RestartCount).String()
+
+	tartRunCmdline, err := tartRunProcessCmdline(tartVMName)
+	require.NoError(t, err)
+	require.NotContains(t, tartRunCmdline, "--net-softnet")
+	require.NotContains(t, tartRunCmdline, "--net-softnet-allow")
+	require.NotContains(t, tartRunCmdline, "--net-softnet-block")
+
+	// Update the VM's specification and enable Softnet
+	vm.NetSoftnetAllow = []string{"10.0.0.0/16"}
+	vm.NetSoftnetBlock = []string{"0.0.0.0/0"}
+
+	vm, err = devClient.VMs().Update(t.Context(), *vm)
+	require.NoError(t, err)
+	require.EqualValues(t, 1, vm.Generation)
+	require.EqualValues(t, 0, vm.ObservedGeneration)
+
+	require.True(t, wait.Wait(30*time.Second, func() bool {
+		vm, err = devClient.VMs().Get(context.Background(), vmName)
+		require.NoError(t, err)
+
+		t.Logf("Waiting for the VM's observed generation to be updated...")
+
+		return vm.ObservedGeneration == 1
+	}), "failed to update a VM")
+
+	tartRunCmdline, err = tartRunProcessCmdline(tartVMName)
+	require.NoError(t, err)
+	require.Contains(t, tartRunCmdline, "--net-softnet")
+	require.True(t, sliceContainsAnotherSlice(tartRunCmdline, []string{"--net-softnet-allow", "10.0.0.0/16"}))
+	require.True(t, sliceContainsAnotherSlice(tartRunCmdline, []string{"--net-softnet-block", "0.0.0.0/0"}))
+}
+
+func tartRunProcessCmdline(vmName string) ([]string, error) {
+	processes, err := process.Processes()
+	if err != nil {
+		return nil, err
+	}
+
+	for _, process := range processes {
+		name, err := process.Name()
+		if err != nil {
+			// On macOS, process.Name() returns "invalid argument" for most
+			// of the processes likely due to permissions, so just ignore it
+			continue
+		}
+
+		if name != "tart" {
+			continue
+		}
+
+		cmdline, err := process.CmdlineSlice()
+		if err != nil {
+			return nil, err
+		}
+
+		if len(cmdline) < 3 {
+			continue
+		}
+
+		if cmdline[1] != "run" {
+			continue
+		}
+
+		if lo.Contains(cmdline[2:], vmName) {
+			return cmdline, nil
+		}
+	}
+
+	return nil, fmt.Errorf("failed to find a \"tart run\" process for VM %q", vmName)
+}
+
+func sliceContainsAnotherSlice(haystack []string, needle []string) bool {
+	if len(needle) == 0 {
+		return true
+	}
+
+	var needleIdx int
+
+	for _, haystackItem := range haystack {
+		if haystackItem == needle[needleIdx] {
+			needleIdx++
+
+			if needleIdx == len(needle) {
+				return true
+			}
+		}
+	}
+
+	return false
+}