cmd/flamenco-manager/main.go

@@ -175,7 +175,7 @@ func runFlamencoManager() bool {
 	shamanServer := buildShamanServer(configService, isFirstRun)
 	jobDeleter := job_deleter.NewService(persist, localStorage, eventBroker, shamanServer)
 
-	farmStatus := farmstatus.NewService(persist)
+	farmStatus := farmstatus.NewService(persist, eventBroker)
 
 	flamenco := api_impl.NewFlamenco(
 		compiler, persist, eventBroker, logStorage, configService,

internal/manager/eventbus/events_farmstatus.go

@@ -0,0 +1,17 @@
+package eventbus
+
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+import (
+	"github.com/rs/zerolog/log"
+	"projects.blender.org/studio/flamenco/pkg/api"
+)
+
+func NewFarmStatusEvent(farmstatus api.FarmStatusReport) api.EventFarmStatus {
+	return api.EventFarmStatus(farmstatus)
+}
+
+func (b *Broker) BroadcastFarmStatusEvent(event api.EventFarmStatus) {
+	log.Debug().Interface("event", event).Msg("eventbus: broadcasting FarmStatus event")
+	b.broadcast(TopicFarmStatus, event)
+}

internal/manager/eventbus/topics.go

@@ -7,6 +7,7 @@ import "fmt"
 const (
 	// Topics on which events are published.
 	TopicLifeCycle         EventTopic = "/lifecycle"     // sends api.EventLifeCycle
+	TopicFarmStatus        EventTopic = "/status"        // sends api.EventFarmStatus
 	TopicJobUpdate         EventTopic = "/jobs"          // sends api.EventJobUpdate
 	TopicLastRenderedImage EventTopic = "/last-rendered" // sends api.EventLastRenderedUpdate
 	TopicTaskUpdate        EventTopic = "/task"          // sends api.EventTaskUpdate

internal/manager/farmstatus/farmstatus.go

@@ -9,6 +9,7 @@ import (
 	"time"
 
 	"github.com/rs/zerolog/log"
+	"projects.blender.org/studio/flamenco/internal/manager/eventbus"
 	"projects.blender.org/studio/flamenco/pkg/api"
 	"projects.blender.org/studio/flamenco/pkg/website"
 )
@@ -25,14 +26,16 @@ const (
 // Service keeps track of the overall farm status.
 type Service struct {
 	persist  PersistenceService
+	eventbus EventBus
 
 	mutex      sync.Mutex
 	lastReport api.FarmStatusReport
 }
 
-func NewService(persist PersistenceService) *Service {
+func NewService(persist PersistenceService, eventbus EventBus) *Service {
 	return &Service{
 		persist:  persist,
+		eventbus: eventbus,
 		mutex:    sync.Mutex{},
 		lastReport: api.FarmStatusReport{
 			Status: api.FarmStatusStarting,
@@ -64,6 +67,18 @@ func (s *Service) Report() api.FarmStatusReport {
 	return s.lastReport
 }
 
+// updateStatusReport updates the last status report in a thread-safe way.
+// It returns whether the report changed.
+func (s *Service) updateStatusReport(report api.FarmStatusReport) bool {
+	s.mutex.Lock()
+	defer s.mutex.Unlock()
+
+	reportChanged := s.lastReport != report
+	s.lastReport = report
+
+	return reportChanged
+}
+
 func (s *Service) poll(ctx context.Context) {
 	report := s.checkFarmStatus(ctx)
 	if report == nil {
@@ -71,9 +86,11 @@ func (s *Service) poll(ctx context.Context) {
 		return
 	}
 
-	s.mutex.Lock()
-	s.lastReport = *report
-	s.mutex.Unlock()
+	reportChanged := s.updateStatusReport(*report)
+	if reportChanged {
+		event := eventbus.NewFarmStatusEvent(s.lastReport)
+		s.eventbus.BroadcastFarmStatusEvent(event)
+	}
 }
 
 // checkFarmStatus checks the farm status by querying the peristence layer.

internal/manager/farmstatus/farmstatus_test.go

@@ -16,6 +16,7 @@ import (
 type Fixtures struct {
 	service  *Service
 	persist  *mocks.MockPersistenceService
+	eventbus *mocks.MockEventBus
 	ctx      context.Context
 }
 
@@ -158,6 +159,29 @@ func TestCheckFarmStatusAsleep(t *testing.T) {
 	assert.Equal(t, api.FarmStatusAsleep, report.Status)
 }
 
+func TestFarmStatusEvent(t *testing.T) {
+	f := fixtures(t)
+
+	// "inoperative": no workers.
+	f.mockWorkerStatuses(persistence.WorkerStatusCount{})
+	f.eventbus.EXPECT().BroadcastFarmStatusEvent(api.EventFarmStatus{
+		Status: api.FarmStatusInoperative,
+	})
+	f.service.poll(f.ctx)
+
+	// Re-polling should not trigger any event, as the status doesn't change.
+	f.mockWorkerStatuses(persistence.WorkerStatusCount{})
+	f.service.poll(f.ctx)
+
+	// "active": Actively working on jobs.
+	f.mockWorkerStatuses(persistence.WorkerStatusCount{api.WorkerStatusAwake: 3})
+	f.mockJobStatuses(persistence.JobStatusCount{api.JobStatusActive: 1})
+	f.eventbus.EXPECT().BroadcastFarmStatusEvent(api.EventFarmStatus{
+		Status: api.FarmStatusActive,
+	})
+	f.service.poll(f.ctx)
+}
+
 func Test_allIn(t *testing.T) {
 	type args struct {
 		statuses   map[api.WorkerStatus]int
@@ -196,10 +220,11 @@ func fixtures(t *testing.T) *Fixtures {
 
 	f := Fixtures{
 		persist:  mocks.NewMockPersistenceService(mockCtrl),
+		eventbus: mocks.NewMockEventBus(mockCtrl),
 		ctx:      context.Background(),
 	}
 
-	f.service = NewService(f.persist)
+	f.service = NewService(f.persist, f.eventbus)
 
 	return &f
 }

internal/manager/farmstatus/interfaces.go

@@ -3,11 +3,13 @@ package farmstatus
 import (
 	"context"
 
+	"projects.blender.org/studio/flamenco/internal/manager/eventbus"
 	"projects.blender.org/studio/flamenco/internal/manager/persistence"
+	"projects.blender.org/studio/flamenco/pkg/api"
 )
 
 // Generate mock implementations of these interfaces.
-//go:generate go run github.com/golang/mock/mockgen -destination mocks/interfaces_mock.gen.go -package mocks projects.blender.org/studio/flamenco/internal/manager/farmstatus PersistenceService
+//go:generate go run github.com/golang/mock/mockgen -destination mocks/interfaces_mock.gen.go -package mocks projects.blender.org/studio/flamenco/internal/manager/farmstatus PersistenceService,EventBus
 
 type PersistenceService interface {
 	SummarizeJobStatuses(ctx context.Context) (persistence.JobStatusCount, error)
@@ -15,3 +17,9 @@ type PersistenceService interface {
 }
 
 var _ PersistenceService = (*persistence.DB)(nil)
+
+type EventBus interface {
+	BroadcastFarmStatusEvent(event api.EventFarmStatus)
+}
+
+var _ EventBus = (*eventbus.Broker)(nil)

internal/manager/farmstatus/mocks/interfaces_mock.gen.go

@@ -1,5 +1,5 @@
 // Code generated by MockGen. DO NOT EDIT.
-// Source: projects.blender.org/studio/flamenco/internal/manager/farmstatus (interfaces: PersistenceService)
+// Source: projects.blender.org/studio/flamenco/internal/manager/farmstatus (interfaces: PersistenceService,EventBus)
 
 // Package mocks is a generated GoMock package.
 package mocks
@@ -10,6 +10,7 @@ import (
 
 	gomock "github.com/golang/mock/gomock"
 	persistence "projects.blender.org/studio/flamenco/internal/manager/persistence"
+	api "projects.blender.org/studio/flamenco/pkg/api"
 )
 
 // MockPersistenceService is a mock of PersistenceService interface.
@@ -64,3 +65,38 @@ func (mr *MockPersistenceServiceMockRecorder) SummarizeWorkerStatuses(arg0 inter
 	mr.mock.ctrl.T.Helper()
 	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "SummarizeWorkerStatuses", reflect.TypeOf((*MockPersistenceService)(nil).SummarizeWorkerStatuses), arg0)
 }
+
+// MockEventBus is a mock of EventBus interface.
+type MockEventBus struct {
+	ctrl     *gomock.Controller
+	recorder *MockEventBusMockRecorder
+}
+
+// MockEventBusMockRecorder is the mock recorder for MockEventBus.
+type MockEventBusMockRecorder struct {
+	mock *MockEventBus
+}
+
+// NewMockEventBus creates a new mock instance.
+func NewMockEventBus(ctrl *gomock.Controller) *MockEventBus {
+	mock := &MockEventBus{ctrl: ctrl}
+	mock.recorder = &MockEventBusMockRecorder{mock}
+	return mock
+}
+
+// EXPECT returns an object that allows the caller to indicate expected use.
+func (m *MockEventBus) EXPECT() *MockEventBusMockRecorder {
+	return m.recorder
+}
+
+// BroadcastFarmStatusEvent mocks base method.
+func (m *MockEventBus) BroadcastFarmStatusEvent(arg0 api.EventFarmStatus) {
+	m.ctrl.T.Helper()
+	m.ctrl.Call(m, "BroadcastFarmStatusEvent", arg0)
+}
+
+// BroadcastFarmStatusEvent indicates an expected call of BroadcastFarmStatusEvent.
+func (mr *MockEventBusMockRecorder) BroadcastFarmStatusEvent(arg0 interface{}) *gomock.Call {
+	mr.mock.ctrl.T.Helper()
+	return mr.mock.ctrl.RecordCallWithMethodType(mr.mock, "BroadcastFarmStatusEvent", reflect.TypeOf((*MockEventBus)(nil).BroadcastFarmStatusEvent), arg0)
+}