Fix builder activity detection and busy-create response

Author: cursoragent

cmd/api/api/builds.go

@@ -276,6 +276,11 @@ func (s *ApiService) CreateBuild(ctx context.Context, request oapi.CreateBuildRe
 				Code:    "not_found",
 				Message: "builder not found",
 			}, nil
+		case errors.Is(err, builders.ErrInUse):
+			return oapi.CreateBuild400JSONResponse{
+				Code:    "conflict",
+				Message: "builder is not ready",
+			}, nil
 		default:
 			log.ErrorContext(ctx, "failed to create build", "error", err)
 			return oapi.CreateBuild500JSONResponse{

cmd/api/api/builds_test.go

@@ -0,0 +1,49 @@
+package api
+
+import (
+	"bytes"
+	"context"
+	"mime/multipart"
+	"testing"
+
+	"github.com/kernel/hypeman/lib/builders"
+	"github.com/kernel/hypeman/lib/builds"
+	"github.com/kernel/hypeman/lib/oapi"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+type createBuildErrManager struct {
+	builds.Manager
+	err error
+}
+
+func (m *createBuildErrManager) CreateBuild(context.Context, builds.CreateBuildRequest, []byte) (*builds.Build, error) {
+	return nil, m.err
+}
+
+func TestCreateBuild_ReturnsBadRequestWhenBuilderBusy(t *testing.T) {
+	svc := newTestService(t)
+	svc.BuildManager = &createBuildErrManager{
+		Manager: svc.BuildManager,
+		err:     builders.ErrInUse,
+	}
+
+	var body bytes.Buffer
+	writer := multipart.NewWriter(&body)
+	sourcePart, err := writer.CreateFormFile("source", "source.tar.gz")
+	require.NoError(t, err)
+	_, err = sourcePart.Write([]byte("fake-source-data"))
+	require.NoError(t, err)
+	require.NoError(t, writer.Close())
+
+	resp, err := svc.CreateBuild(ctx(), oapi.CreateBuildRequestObject{
+		Body: multipart.NewReader(bytes.NewReader(body.Bytes()), writer.Boundary()),
+	})
+	require.NoError(t, err)
+
+	badReq, ok := resp.(oapi.CreateBuild400JSONResponse)
+	require.True(t, ok, "expected a 400 when builder is busy")
+	assert.Equal(t, "conflict", badReq.Code)
+	assert.Equal(t, "builder is not ready", badReq.Message)
+}

lib/builds/builder_disk_test.go

@@ -459,3 +459,22 @@ func TestBuilderHasBuilds_CountsDiskPendingBeforeRecovery(t *testing.T) {
 	mgr.RecoverPendingBuilds()
 	assert.False(t, mgr.BuilderHasBuilds("builder-a"))
 }
+
+// TestBuilderHasBuilds_CountsDiskBuildingAfterRecovery verifies a build that
+// is still building on disk remains visible to builder activity checks even
+// after startup recovery has completed.
+func TestBuilderHasBuilds_CountsDiskBuildingAfterRecovery(t *testing.T) {
+	mgr, _, _, tempDir := setupTestManager(t)
+	defer os.RemoveAll(tempDir)
+
+	require.NoError(t, writeMetadata(mgr.paths, &buildMetadata{
+		ID:        "build-post-vm",
+		Status:    StatusBuilding,
+		Request:   &CreateBuildRequest{BuilderID: "builder-a"},
+		CreatedAt: time.Now(),
+	}))
+	mgr.pendingRecovered.Store(true)
+
+	assert.True(t, mgr.BuilderHasBuilds("builder-a"), "building metadata must count after recovery")
+	assert.False(t, mgr.BuilderHasBuilds("builder-b"))
+}

lib/builds/manager.go

@@ -148,8 +148,7 @@ type manager struct {
 	createMu        sync.Mutex
 	builderReady    atomic.Bool
 	// pendingRecovered is set once RecoverPendingBuilds has re-enqueued
-	// persisted pending builds; until then BuilderHasBuilds also scans
-	// disk so delete, prune, and the idle reaper see them.
+	// persisted pending builds.
 	pendingRecovered atomic.Bool
 
 	// Status subscription system for SSE streaming
@@ -599,15 +598,11 @@ func (m *manager) QueuedBuildsForBuilder(builderID string) []string {
 }
 
 // BuilderHasBuilds reports whether any build targeting the builder is
-// queued or running. Until startup recovery completes, persisted pending
-// builds are not in the queue yet, so they are matched on disk.
+// queued or running, including persisted queued/building metadata.
 func (m *manager) BuilderHasBuilds(builderID string) bool {
 	if m.queue.HasSerialKey(builderID) {
 		return true
 	}
-	if m.pendingRecovered.Load() {
-		return false
-	}
 	pending, err := listPendingBuilds(m.paths)
 	if err != nil {
 		// Fail closed: blocking a delete is recoverable, deleting a