client/go: LazyBrowseNode walker for lazy hierarchy browse

clients/go/mxgateway/galaxy.go

@@ -3,7 +3,9 @@ package mxgateway
 import (
 	"context"
 	"errors"
+	"fmt"
 	"io"
+	"sync"
 	"time"
 
 	pb "gitea.dohertylan.com/dohertj2/mxaccessgw/clients/go/internal/generated"
@@ -13,6 +15,9 @@ import (
 	"google.golang.org/protobuf/types/known/timestamppb"
 )
 
+// browseChildrenPageSize is the per-request page size used by the lazy walker.
+const browseChildrenPageSize = 500
+
 // RawGalaxyRepositoryClient is the generated gRPC client interface for the
 // Galaxy Repository service exposed for callers that need direct contract
 // access.
@@ -40,6 +45,10 @@ type (
 	WatchDeployEventsRequest = pb.WatchDeployEventsRequest
 	// DeployEvent is one Galaxy Repository deploy event.
 	DeployEvent = pb.DeployEvent
+	// BrowseChildrenRequest is the request for BrowseChildren.
+	BrowseChildrenRequest = pb.BrowseChildrenRequest
+	// BrowseChildrenReply is the reply for BrowseChildren.
+	BrowseChildrenReply = pb.BrowseChildrenReply
 )
 
 // RawDeployEventStream is the generated WatchDeployEvents client stream.
@@ -238,6 +247,140 @@ func (c *GalaxyClient) Close() error {
 	return c.conn.Close()
 }
 
+// LazyBrowseNode is one node in a lazy Galaxy hierarchy walk produced by
+// (*GalaxyClient).Browse. Children are not fetched until Expand is called.
+// The node is safe for concurrent use; concurrent Expand calls collapse to a
+// single RPC.
+type LazyBrowseNode struct {
+	client          *GalaxyClient
+	object          *pb.GalaxyObject
+	hasChildrenHint bool
+	options         BrowseChildrenOptions
+
+	mu         sync.Mutex
+	children   []*LazyBrowseNode
+	isExpanded bool
+}
+
+// Object returns the underlying GalaxyObject describing this node.
+func (n *LazyBrowseNode) Object() *pb.GalaxyObject { return n.object }
+
+// HasChildrenHint reports the server-supplied hint on whether this node has
+// matching descendants under the current filter set.
+func (n *LazyBrowseNode) HasChildrenHint() bool { return n.hasChildrenHint }
+
+// Children returns a snapshot copy of the currently-loaded child nodes. Returns
+// an empty slice when Expand has not yet been called.
+func (n *LazyBrowseNode) Children() []*LazyBrowseNode {
+	n.mu.Lock()
+	defer n.mu.Unlock()
+	out := make([]*LazyBrowseNode, len(n.children))
+	copy(out, n.children)
+	return out
+}
+
+// IsExpanded reports whether Expand has completed successfully on this node.
+func (n *LazyBrowseNode) IsExpanded() bool {
+	n.mu.Lock()
+	defer n.mu.Unlock()
+	return n.isExpanded
+}
+
+// Expand fetches this node's direct children via BrowseChildren when they have
+// not yet been loaded. Subsequent calls after a successful Expand are a no-op
+// and do not issue another RPC.
+func (n *LazyBrowseNode) Expand(ctx context.Context) error {
+	n.mu.Lock()
+	defer n.mu.Unlock()
+	if n.isExpanded {
+		return nil
+	}
+	parentID := n.object.GetGobjectId()
+	children, err := n.client.browseChildrenInner(ctx, &parentID, n.options)
+	if err != nil {
+		return err
+	}
+	n.children = children
+	n.isExpanded = true
+	return nil
+}
+
+// Browse returns the root nodes of the Galaxy hierarchy. The returned nodes
+// have only their server-supplied hints populated; call Expand on each node to
+// fetch its direct children. When opts is nil the server defaults apply.
+func (c *GalaxyClient) Browse(ctx context.Context, opts *BrowseChildrenOptions) ([]*LazyBrowseNode, error) {
+	effective := BrowseChildrenOptions{}
+	if opts != nil {
+		effective = *opts
+	}
+	return c.browseChildrenInner(ctx, nil, effective)
+}
+
+// BrowseChildrenRaw issues a single BrowseChildren RPC and returns the raw
+// reply for callers that need direct page-token control. Transport-level
+// failures are wrapped in *GatewayError to match the rest of the client.
+func (c *GalaxyClient) BrowseChildrenRaw(ctx context.Context, req *pb.BrowseChildrenRequest) (*pb.BrowseChildrenReply, error) {
+	callCtx, cancel := c.callContext(ctx)
+	defer cancel()
+	reply, err := c.raw.BrowseChildren(callCtx, req)
+	if err != nil {
+		return nil, &GatewayError{Op: "galaxy browse children", Err: err}
+	}
+	return reply, nil
+}
+
+func (c *GalaxyClient) browseChildrenInner(
+	ctx context.Context,
+	parentGobjectID *int32,
+	opts BrowseChildrenOptions,
+) ([]*LazyBrowseNode, error) {
+	var nodes []*LazyBrowseNode
+	pageToken := ""
+	seen := map[string]struct{}{}
+	for {
+		req := &pb.BrowseChildrenRequest{
+			PageSize:              browseChildrenPageSize,
+			PageToken:             pageToken,
+			CategoryIds:           opts.CategoryIds,
+			TemplateChainContains: opts.TemplateChainContains,
+			TagNameGlob:           opts.TagNameGlob,
+			AlarmBearingOnly:      opts.AlarmBearingOnly,
+			HistorizedOnly:        opts.HistorizedOnly,
+		}
+		if parentGobjectID != nil {
+			req.Parent = &pb.BrowseChildrenRequest_ParentGobjectId{ParentGobjectId: *parentGobjectID}
+		}
+		if opts.IncludeAttributes != nil {
+			req.IncludeAttributes = opts.IncludeAttributes
+		}
+
+		reply, err := c.BrowseChildrenRaw(ctx, req)
+		if err != nil {
+			return nil, err
+		}
+
+		for i, child := range reply.GetChildren() {
+			hasChildren := reply.GetChildHasChildren()
+			hint := i < len(hasChildren) && hasChildren[i]
+			nodes = append(nodes, &LazyBrowseNode{
+				client:          c,
+				object:          child,
+				hasChildrenHint: hint,
+				options:         opts,
+			})
+		}
+
+		pageToken = reply.GetNextPageToken()
+		if pageToken == "" {
+			return nodes, nil
+		}
+		if _, dup := seen[pageToken]; dup {
+			return nil, fmt.Errorf("mxgateway: galaxy browse children returned repeated page token %q", pageToken)
+		}
+		seen[pageToken] = struct{}{}
+	}
+}
+
 func (c *GalaxyClient) callContext(ctx context.Context) (context.Context, context.CancelFunc) {
 	timeout := c.opts.CallTimeout
 	if timeout == 0 {

clients/go/mxgateway/galaxy_test.go

@@ -9,6 +9,8 @@ import (
 
 	pb "gitea.dohertylan.com/dohertj2/mxaccessgw/clients/go/internal/generated"
 	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
 	"google.golang.org/grpc/test/bufconn"
 	"google.golang.org/protobuf/types/known/timestamppb"
 )
@@ -370,15 +372,18 @@ func newGalaxyBufconnClient(t *testing.T, fake *fakeGalaxyServer) (*GalaxyClient
 type fakeGalaxyServer struct {
 	pb.UnimplementedGalaxyRepositoryServer
 
-	testReply         *pb.TestConnectionReply
-	testAuth          string
-	failTest          bool
-	deployReply       *pb.GetLastDeployTimeReply
-	discoverReply     *pb.DiscoverHierarchyReply
-	watchEvents       []*pb.DeployEvent
-	watchRequest      *pb.WatchDeployEventsRequest
-	watchSendInterval time.Duration
-	watchHoldOpen     bool
+	testReply             *pb.TestConnectionReply
+	testAuth              string
+	failTest              bool
+	deployReply           *pb.GetLastDeployTimeReply
+	discoverReply         *pb.DiscoverHierarchyReply
+	watchEvents           []*pb.DeployEvent
+	watchRequest          *pb.WatchDeployEventsRequest
+	watchSendInterval     time.Duration
+	watchHoldOpen         bool
+	browseChildrenCalls   []*pb.BrowseChildrenRequest
+	browseChildrenReplies []*pb.BrowseChildrenReply
+	browseChildrenError   error
 }
 
 func (s *fakeGalaxyServer) TestConnection(ctx context.Context, req *pb.TestConnectionRequest) (*pb.TestConnectionReply, error) {
@@ -425,3 +430,311 @@ func (s *fakeGalaxyServer) WatchDeployEvents(req *pb.WatchDeployEventsRequest, s
 	}
 	return nil
 }
+
+func (s *fakeGalaxyServer) BrowseChildren(ctx context.Context, req *pb.BrowseChildrenRequest) (*pb.BrowseChildrenReply, error) {
+	s.browseChildrenCalls = append(s.browseChildrenCalls, req)
+	if s.browseChildrenError != nil {
+		err := s.browseChildrenError
+		s.browseChildrenError = nil
+		return nil, err
+	}
+	if len(s.browseChildrenReplies) == 0 {
+		return &pb.BrowseChildrenReply{}, nil
+	}
+	reply := s.browseChildrenReplies[0]
+	s.browseChildrenReplies = s.browseChildrenReplies[1:]
+	return reply, nil
+}
+
+func obj(id int32, tag string, isArea bool) *pb.GalaxyObject {
+	return &pb.GalaxyObject{
+		GobjectId:  id,
+		TagName:    tag,
+		BrowseName: tag,
+		IsArea:     isArea,
+	}
+}
+
+func buildBrowseReply(children []*pb.GalaxyObject, hasChildren []bool, seq uint64) *pb.BrowseChildrenReply {
+	return &pb.BrowseChildrenReply{
+		TotalChildCount:  int32(len(children)),
+		CacheSequence:    seq,
+		Children:         children,
+		ChildHasChildren: hasChildren,
+	}
+}
+
+func TestGalaxyBrowseNoParentReturnsRoots(t *testing.T) {
+	fake := &fakeGalaxyServer{
+		browseChildrenReplies: []*pb.BrowseChildrenReply{
+			buildBrowseReply(
+				[]*pb.GalaxyObject{obj(1, "Plant", true), obj(99, "Other", false)},
+				[]bool{true, false},
+				7,
+			),
+		},
+	}
+	client, cleanup := newGalaxyBufconnClient(t, fake)
+	defer cleanup()
+
+	roots, err := client.Browse(context.Background(), nil)
+	if err != nil {
+		t.Fatalf("Browse: %v", err)
+	}
+	if got, want := len(roots), 2; got != want {
+		t.Fatalf("len(roots) = %d, want %d", got, want)
+	}
+	if roots[0].Object().GetTagName() != "Plant" {
+		t.Fatalf("roots[0].TagName = %q", roots[0].Object().GetTagName())
+	}
+	if !roots[0].HasChildrenHint() {
+		t.Fatal("roots[0].HasChildrenHint = false, want true")
+	}
+	if roots[0].IsExpanded() {
+		t.Fatal("roots[0].IsExpanded = true, want false")
+	}
+	if roots[1].HasChildrenHint() {
+		t.Fatal("roots[1].HasChildrenHint = true, want false")
+	}
+	if len(fake.browseChildrenCalls) != 1 {
+		t.Fatalf("BrowseChildren calls = %d, want 1", len(fake.browseChildrenCalls))
+	}
+	if fake.browseChildrenCalls[0].GetParent() != nil {
+		t.Fatalf("root browse should not set Parent oneof, got %T", fake.browseChildrenCalls[0].GetParent())
+	}
+}
+
+func TestGalaxyBrowseExpandPopulatesChildrenAndMarksExpanded(t *testing.T) {
+	fake := &fakeGalaxyServer{
+		browseChildrenReplies: []*pb.BrowseChildrenReply{
+			buildBrowseReply(
+				[]*pb.GalaxyObject{obj(1, "Plant", true)},
+				[]bool{true},
+				1,
+			),
+			buildBrowseReply(
+				[]*pb.GalaxyObject{obj(10, "Area1", true), obj(11, "Tank1", false)},
+				[]bool{true, false},
+				1,
+			),
+		},
+	}
+	client, cleanup := newGalaxyBufconnClient(t, fake)
+	defer cleanup()
+
+	roots, err := client.Browse(context.Background(), nil)
+	if err != nil {
+		t.Fatalf("Browse: %v", err)
+	}
+	if len(roots) != 1 {
+		t.Fatalf("len(roots) = %d, want 1", len(roots))
+	}
+	plant := roots[0]
+	if plant.IsExpanded() {
+		t.Fatal("plant.IsExpanded = true before Expand, want false")
+	}
+	if err := plant.Expand(context.Background()); err != nil {
+		t.Fatalf("Expand: %v", err)
+	}
+	if !plant.IsExpanded() {
+		t.Fatal("plant.IsExpanded = false after Expand, want true")
+	}
+	children := plant.Children()
+	if len(children) != 2 {
+		t.Fatalf("len(children) = %d, want 2", len(children))
+	}
+	if children[0].Object().GetTagName() != "Area1" {
+		t.Fatalf("children[0].TagName = %q, want Area1", children[0].Object().GetTagName())
+	}
+	if !children[0].HasChildrenHint() {
+		t.Fatal("children[0].HasChildrenHint = false, want true")
+	}
+	if children[1].HasChildrenHint() {
+		t.Fatal("children[1].HasChildrenHint = true, want false")
+	}
+	if len(fake.browseChildrenCalls) != 2 {
+		t.Fatalf("BrowseChildren calls = %d, want 2", len(fake.browseChildrenCalls))
+	}
+	parent := fake.browseChildrenCalls[1].GetParent()
+	parentGobj, ok := parent.(*pb.BrowseChildrenRequest_ParentGobjectId)
+	if !ok {
+		t.Fatalf("Parent oneof = %T, want *BrowseChildrenRequest_ParentGobjectId", parent)
+	}
+	if parentGobj.ParentGobjectId != 1 {
+		t.Fatalf("ParentGobjectId = %d, want 1", parentGobj.ParentGobjectId)
+	}
+}
+
+func TestGalaxyBrowseExpandIdempotentNoSecondRpc(t *testing.T) {
+	fake := &fakeGalaxyServer{
+		browseChildrenReplies: []*pb.BrowseChildrenReply{
+			buildBrowseReply(
+				[]*pb.GalaxyObject{obj(1, "Plant", true)},
+				[]bool{true},
+				1,
+			),
+			buildBrowseReply(
+				[]*pb.GalaxyObject{obj(10, "Area1", true)},
+				[]bool{false},
+				1,
+			),
+		},
+	}
+	client, cleanup := newGalaxyBufconnClient(t, fake)
+	defer cleanup()
+
+	roots, err := client.Browse(context.Background(), nil)
+	if err != nil {
+		t.Fatalf("Browse: %v", err)
+	}
+	plant := roots[0]
+	if err := plant.Expand(context.Background()); err != nil {
+		t.Fatalf("Expand #1: %v", err)
+	}
+	callsAfterFirst := len(fake.browseChildrenCalls)
+	if callsAfterFirst != 2 {
+		t.Fatalf("BrowseChildren calls after first Expand = %d, want 2", callsAfterFirst)
+	}
+	if err := plant.Expand(context.Background()); err != nil {
+		t.Fatalf("Expand #2: %v", err)
+	}
+	if got := len(fake.browseChildrenCalls); got != callsAfterFirst {
+		t.Fatalf("BrowseChildren calls after second Expand = %d, want %d (no extra RPC)", got, callsAfterFirst)
+	}
+}
+
+func TestGalaxyBrowseExpandUnknownParentReturnsNotFoundError(t *testing.T) {
+	fake := &fakeGalaxyServer{
+		browseChildrenReplies: []*pb.BrowseChildrenReply{
+			buildBrowseReply(
+				[]*pb.GalaxyObject{obj(1, "Plant", true)},
+				[]bool{true},
+				1,
+			),
+		},
+		browseChildrenError: status.Error(codes.NotFound, "parent not found"),
+	}
+	// The first Browse() consumes the first reply; the next call (Expand) will
+	// then hit browseChildrenError. We need the error to fire only on the second
+	// call, so seed the reply first and let the call sequence consume them in
+	// order. Because BrowseChildren in the fake consumes browseChildrenError
+	// before falling through to replies, swap the strategy: keep the root reply
+	// but have BrowseChildren return the error on the second call. We do this by
+	// emptying the reply list after the first Browse.
+	client, cleanup := newGalaxyBufconnClient(t, fake)
+	defer cleanup()
+
+	// First call returns the error (because browseChildrenError takes precedence).
+	// To avoid that, clear it for the root call by performing a manual setup: we
+	// pre-stage replies first, then set the error after the first call. Easiest:
+	// pre-Browse() with error=nil, then set error before Expand.
+	fake.browseChildrenError = nil
+	roots, err := client.Browse(context.Background(), nil)
+	if err != nil {
+		t.Fatalf("Browse: %v", err)
+	}
+	if len(roots) != 1 {
+		t.Fatalf("len(roots) = %d, want 1", len(roots))
+	}
+	fake.browseChildrenError = status.Error(codes.NotFound, "parent not found")
+
+	err = roots[0].Expand(context.Background())
+	if err == nil {
+		t.Fatal("Expand: error = nil, want NotFound")
+	}
+	if status.Code(err) != codes.NotFound {
+		t.Fatalf("status.Code = %s, want NotFound", status.Code(err))
+	}
+	if roots[0].IsExpanded() {
+		t.Fatal("roots[0].IsExpanded = true after failed Expand, want false")
+	}
+}
+
+func TestGalaxyBrowseExpandMultiPageGathersAllPages(t *testing.T) {
+	firstPage := buildBrowseReply(
+		[]*pb.GalaxyObject{obj(1, "Plant", true)},
+		[]bool{true},
+		7,
+	)
+
+	pageA := buildBrowseReply(
+		[]*pb.GalaxyObject{obj(10, "Child1", false), obj(11, "Child2", false)},
+		[]bool{false, false},
+		7,
+	)
+	pageA.NextPageToken = "7:abc:2"
+	pageB := buildBrowseReply(
+		[]*pb.GalaxyObject{obj(12, "Child3", false)},
+		[]bool{false},
+		7,
+	)
+
+	fake := &fakeGalaxyServer{
+		browseChildrenReplies: []*pb.BrowseChildrenReply{firstPage, pageA, pageB},
+	}
+	client, cleanup := newGalaxyBufconnClient(t, fake)
+	defer cleanup()
+
+	roots, err := client.Browse(context.Background(), nil)
+	if err != nil {
+		t.Fatalf("Browse: %v", err)
+	}
+	if err := roots[0].Expand(context.Background()); err != nil {
+		t.Fatalf("Expand: %v", err)
+	}
+	children := roots[0].Children()
+	if len(children) != 3 {
+		t.Fatalf("len(children) = %d, want 3", len(children))
+	}
+	if len(fake.browseChildrenCalls) != 3 {
+		t.Fatalf("BrowseChildren calls = %d, want 3", len(fake.browseChildrenCalls))
+	}
+	if got := fake.browseChildrenCalls[2].GetPageToken(); got != "7:abc:2" {
+		t.Fatalf("third call PageToken = %q, want %q", got, "7:abc:2")
+	}
+}
+
+func TestGalaxyBrowseWithFilterForwardsToRequest(t *testing.T) {
+	fake := &fakeGalaxyServer{
+		browseChildrenReplies: []*pb.BrowseChildrenReply{
+			buildBrowseReply(nil, nil, 1),
+		},
+	}
+	client, cleanup := newGalaxyBufconnClient(t, fake)
+	defer cleanup()
+
+	include := true
+	opts := &BrowseChildrenOptions{
+		CategoryIds:           []int32{7, 9},
+		TemplateChainContains: []string{"$AppObject"},
+		TagNameGlob:           "Tank*",
+		IncludeAttributes:     &include,
+		AlarmBearingOnly:      true,
+		HistorizedOnly:        true,
+	}
+	if _, err := client.Browse(context.Background(), opts); err != nil {
+		t.Fatalf("Browse: %v", err)
+	}
+	if len(fake.browseChildrenCalls) != 1 {
+		t.Fatalf("BrowseChildren calls = %d, want 1", len(fake.browseChildrenCalls))
+	}
+	got := fake.browseChildrenCalls[0]
+	if want := []int32{7, 9}; len(got.GetCategoryIds()) != 2 || got.GetCategoryIds()[0] != want[0] || got.GetCategoryIds()[1] != want[1] {
+		t.Fatalf("CategoryIds = %v, want %v", got.GetCategoryIds(), want)
+	}
+	if want := []string{"$AppObject"}; len(got.GetTemplateChainContains()) != 1 || got.GetTemplateChainContains()[0] != want[0] {
+		t.Fatalf("TemplateChainContains = %v, want %v", got.GetTemplateChainContains(), want)
+	}
+	if got.GetTagNameGlob() != "Tank*" {
+		t.Fatalf("TagNameGlob = %q, want %q", got.GetTagNameGlob(), "Tank*")
+	}
+	if !got.GetIncludeAttributes() {
+		t.Fatal("IncludeAttributes = false, want true")
+	}
+	if !got.GetAlarmBearingOnly() {
+		t.Fatal("AlarmBearingOnly = false, want true")
+	}
+	if !got.GetHistorizedOnly() {
+		t.Fatal("HistorizedOnly = false, want true")
+	}
+}

clients/go/mxgateway/options.go

@@ -36,6 +36,28 @@ type Options struct {
 	DialOptions []grpc.DialOption
 }
 
+// BrowseChildrenOptions configures lazy Galaxy hierarchy walks performed by
+// (*GalaxyClient).Browse and (*LazyBrowseNode).Expand. All fields are optional;
+// the zero value matches the dashboard default (no filters, all attributes per
+// the server default).
+type BrowseChildrenOptions struct {
+	// CategoryIds restricts results to the listed Galaxy category ids when set.
+	CategoryIds []int32
+	// TemplateChainContains restricts results to objects whose template chain
+	// contains any of the listed template tag names.
+	TemplateChainContains []string
+	// TagNameGlob restricts results to objects whose tag name matches the glob
+	// pattern when non-empty.
+	TagNameGlob string
+	// IncludeAttributes overrides the server default for attribute inclusion when
+	// non-nil. The pointer form mirrors the proto's optional field.
+	IncludeAttributes *bool
+	// AlarmBearingOnly limits results to alarm-bearing objects when true.
+	AlarmBearingOnly bool
+	// HistorizedOnly limits results to historized objects when true.
+	HistorizedOnly bool
+}
+
 // RedactedAPIKey returns a display-safe representation of the configured API
 // key for diagnostics and CLI output.
 func (o Options) RedactedAPIKey() string {