Implement server-side filtering for VMs by worker (#392)

* Implement server-side filtering for VMs by worker

* Parse more than one filter but error out when more than one is provided

* Fix off-by-one

* No need to use "\n" in Debugf()

pkg/client/option.go

@@ -2,8 +2,11 @@ package client
 
 import (
 	"crypto/x509"
+	"fmt"
+	"strings"
 
 	"github.com/cirruslabs/orchard/internal/dialer"
+	v1 "github.com/cirruslabs/orchard/pkg/resource/v1"
 )
 
 type Option func(*Client)
@@ -32,3 +35,25 @@ func WithDialer(dialer dialer.Dialer) Option {
 		client.dialer = dialer
 	}
 }
+
+type ListInput struct {
+	Filters []v1.Filter
+}
+
+type ListOption func(params map[string]string)
+
+func WithListFilters(filters ...v1.Filter) ListOption {
+	return func(params map[string]string) {
+		if len(filters) == 0 {
+			return
+		}
+
+		var pairs []string
+
+		for _, filter := range filters {
+			pairs = append(pairs, fmt.Sprintf("%s=%s", filter.Path, filter.Value))
+		}
+
+		params["filter"] = strings.Join(pairs, ",")
+	}
+}

pkg/client/vms.go

@@ -57,13 +57,18 @@ func (service *VMsService) Create(ctx context.Context, vm *v1.VM) error {
 }
 
 func (service *VMsService) FindForWorker(ctx context.Context, worker string) ([]v1.VM, error) {
-	allVms, err := service.List(ctx)
+	allVms, err := service.List(ctx, WithListFilters(v1.Filter{
+		Path:  "worker",
+		Value: worker,
+	}))
 	if err != nil {
 		return nil, err
 	}
 
 	var result []v1.VM
 
+	// Backwards compatibility with older Orchard Controllers
+	// that do not support the "filter" query parameter
 	for _, vmResource := range allVms {
 		if vmResource.Worker != worker {
 			continue
@@ -75,11 +80,18 @@ func (service *VMsService) FindForWorker(ctx context.Context, worker string) ([]
 	return result, nil
 }
 
-func (service *VMsService) List(ctx context.Context) ([]v1.VM, error) {
+func (service *VMsService) List(ctx context.Context, opts ...ListOption) ([]v1.VM, error) {
+	params := map[string]string{}
+
+	// Apply options
+	for _, opt := range opts {
+		opt(params)
+	}
+
 	var vms []v1.VM
 
 	err := service.client.request(ctx, http.MethodGet, "vms",
-		nil, &vms, nil)
+		nil, &vms, params)
 	if err != nil {
 		return nil, err
 	}

pkg/resource/v1/filter.go

@@ -0,0 +1,31 @@
+package v1
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+)
+
+var ErrInvalidFilter = errors.New("invalid filter")
+
+type Filter struct {
+	Path  string
+	Value string
+}
+
+func NewFilter(s string) (Filter, error) {
+	parts := strings.SplitN(s, "=", 2)
+
+	if len(parts) != 2 {
+		return Filter{}, fmt.Errorf("%w: expected path=value", ErrInvalidFilter)
+	}
+
+	if parts[0] == "" {
+		return Filter{}, fmt.Errorf("%w: path cannot be empty", ErrInvalidFilter)
+	}
+
+	return Filter{
+		Path:  parts[0],
+		Value: parts[1],
+	}, nil
+}

pkg/resource/v1/filter_test.go

@@ -0,0 +1,55 @@
+package v1_test
+
+import (
+	"testing"
+
+	v1 "github.com/cirruslabs/orchard/pkg/resource/v1"
+	"github.com/stretchr/testify/require"
+)
+
+func TestNewFilter(t *testing.T) {
+	testCases := []struct {
+		Name  string
+		Input string
+		Err   error
+		Path  string
+		Value string
+	}{
+		{
+			Name:  "simple",
+			Input: "a.b.c=value",
+			Path:  "a.b.c",
+			Value: "value",
+		},
+		{
+			Name:  "value with equals",
+			Input: "a.b.c=d=e",
+			Path:  "a.b.c",
+			Value: "d=e",
+		},
+		{
+			Name:  "empty value",
+			Input: "a.b.c=",
+			Path:  "a.b.c",
+		},
+		{
+			Name:  "missing value",
+			Input: "abc",
+			Err:   v1.ErrInvalidFilter,
+		},
+		{
+			Name:  "missing path",
+			Input: "=value",
+			Err:   v1.ErrInvalidFilter,
+		},
+	}
+
+	for _, testCase := range testCases {
+		t.Run(testCase.Name, func(t *testing.T) {
+			filter, err := v1.NewFilter(testCase.Input)
+			require.ErrorIs(t, err, testCase.Err)
+			require.Equal(t, testCase.Path, filter.Path)
+			require.Equal(t, testCase.Value, filter.Value)
+		})
+	}
+}

pkg/resource/v1/service_account.go

@@ -8,3 +8,7 @@ type ServiceAccount struct {
 }
 
 func (serviceAccount *ServiceAccount) SetVersion(_ uint64) {}
+
+func (serviceAccount *ServiceAccount) Match(filter Filter) bool {
+	return false
+}

pkg/resource/v1/v1.go

@@ -102,6 +102,15 @@ func (vm *VM) SetVersion(version uint64) {
 	vm.Version = version
 }
 
+func (vm *VM) Match(filter Filter) bool {
+	switch filter.Path {
+	case "worker":
+		return vm.Worker == filter.Value
+	default:
+		return false
+	}
+}
+
 func (vm *VM) IsScheduled() bool {
 	if ConditionExists(vm.Conditions, ConditionTypeScheduled) {
 		return ConditionIsTrue(vm.Conditions, ConditionTypeScheduled)

pkg/resource/v1/worker.go

@@ -32,3 +32,7 @@ func (worker Worker) Offline(workerOfflineTimeout time.Duration) bool {
 }
 
 func (worker *Worker) SetVersion(_ uint64) {}
+
+func (worker *Worker) Match(filter Filter) bool {
+	return false
+}