adjust features pkg and don't send featuresFlag if nil

go.mod

@@ -161,4 +161,4 @@ replace (
 // Exclude this version because the version has an invalid checksum.
 exclude github.com/docker/distribution v2.8.0+incompatible
 
-replace github.com/elastic/elastic-agent-client/v7 => github.com/AndersonQ/elastic-agent-client/v7 v7.0.0-20230227212100-3ecfad4b2b6a
+replace github.com/elastic/elastic-agent-client/v7 => github.com/AndersonQ/elastic-agent-client/v7 v7.0.0-20230228215808-7bea0d6b73be

go.sum

@@ -49,8 +49,8 @@ cloud.google.com/go/storage v1.8.0/go.mod h1:Wv1Oy7z6Yz3DshWRJFhqM/UCfaWIRTdp0RX
 cloud.google.com/go/storage v1.10.0/go.mod h1:FLPqc6j+Ki4BU591ie1oL6qBQGu2Bl/tZ9ullr3+Kg0=
 dmitri.shuralyov.com/gpu/mtl v0.0.0-20190408044501-666a987793e9/go.mod h1:H6x//7gZCb22OMCxBHrMx7a5I7Hp++hsVxbQ4BYO7hU=
 github.com/AlecAivazis/survey/v2 v2.3.2/go.mod h1:TH2kPCDU3Kqq7pLbnCWwZXDBjnhZtmsCle5EiYDJ2fg=
-github.com/AndersonQ/elastic-agent-client/v7 v7.0.0-20230227212100-3ecfad4b2b6a h1:4KXiwYssK4WHhpI6hyb8gACtCH3ijwxcKTboizgdoL8=
-github.com/AndersonQ/elastic-agent-client/v7 v7.0.0-20230227212100-3ecfad4b2b6a/go.mod h1:UlVOHSDvTA4Mfdhdg+BE7aqOsUR3ab+x2Zl0aHlBXs4=
+github.com/AndersonQ/elastic-agent-client/v7 v7.0.0-20230228215808-7bea0d6b73be h1:ELXZzC/Inb0C7/4CJ9K6chVxSeUZNSTxPQSIJmbVnuQ=
+github.com/AndersonQ/elastic-agent-client/v7 v7.0.0-20230228215808-7bea0d6b73be/go.mod h1:UlVOHSDvTA4Mfdhdg+BE7aqOsUR3ab+x2Zl0aHlBXs4=
 github.com/Azure/azure-sdk-for-go v16.2.1+incompatible/go.mod h1:9XXNKU+eRnpl9moKnB4QOLf1HestfXbmab5FXxiDBjc=
 github.com/Azure/azure-sdk-for-go v56.3.0+incompatible/go.mod h1:9XXNKU+eRnpl9moKnB4QOLf1HestfXbmab5FXxiDBjc=
 github.com/Azure/go-ansiterm v0.0.0-20170929234023-d6e3b3328b78/go.mod h1:LmzpDX56iTiv29bbRTIsUNlaFfuhWRQBWjQdVyAevI8=

internal/pkg/agent/application/application.go

@@ -70,7 +70,7 @@ func New(
 		return nil, fmt.Errorf("failed to load configuration: %w", err)
 	}
 
-	if _, err := features.Apply(rawConfig); err != nil {
+	if err := features.Apply(rawConfig); err != nil {
 		return nil, fmt.Errorf("could not parse and apply feature falgs config: %w", err)
 	}
 

internal/pkg/agent/application/coordinator/coordinator.go

@@ -686,7 +686,7 @@ func (c *Coordinator) processConfig(ctx context.Context, cfg *config.Config) (er
 		}
 	}
 
-	if _, err := features.Apply(cfg); err != nil {
+	if err := features.Apply(cfg); err != nil {
 		return fmt.Errorf("could not update feature flags config: %w", err)
 	}
 

pkg/component/runtime/manager.go

@@ -505,7 +505,7 @@ func (m *Manager) Subscribe(ctx context.Context, componentID string) *Subscripti
 func (m *Manager) SubscribeAll(ctx context.Context) *SubscriptionAll {
 	sub := newSubscriptionAll(ctx, m)
 
-	// add latest states
+	// add the latest states
 	m.mx.RLock()
 	latest := make([]ComponentComponentState, 0, len(m.current))
 	for _, comp := range m.current {

pkg/component/runtime/manager_test.go

@@ -382,6 +382,7 @@ func TestManager_FakeInput_Features(t *testing.T) {
 						comp.Features = &proto.Features{
 							Fqdn: &proto.FQDNFeature{Enabled: true},
 						}
+
 						err := m.Update([]component.Component{comp})
 						if err != nil {
 							subscriptionErrCh <- fmt.Errorf("[case %d]: failed to update component: %w",
@@ -446,14 +447,6 @@ func TestManager_FakeInput_Features(t *testing.T) {
 						}
 						assert.True(t, ff.FQDN)
 
-						// Change something, but feature flags
-						comp.Units[0].LogLevel = client.UnitLogLevelInfo
-						comp.Units[0].Config = component.MustExpectedConfig(map[string]interface{}{
-							"type":    "fake",
-							"state":   int(client.UnitStateConfiguring),
-							"message": "Fake Healthy",
-						})
-
 						doneCh <- struct{}{}
 						return
 					}

pkg/component/runtime/state.go

@@ -173,7 +173,8 @@ func (s *ComponentState) syncExpected(comp *component.Component) bool {
 		}
 	}
 
-	if !gproto.Equal(s.expectedFeatures, comp.Features) {
+	if s.expectedFeatures != nil &&
+		!gproto.Equal(s.expectedFeatures, comp.Features) {
 		changed = true
 		s.expectedFeaturesIdx++
 		s.expectedFeatures = comp.Features

pkg/features/features.go

@@ -26,10 +26,10 @@ type Flags struct {
 // Parse receives a policy, parses and returns it.
 // policy can be a *config.Config, config.Config or anything config.NewConfigFrom
 // can work with. If policy is nil, Parse is a no-op.
-func Parse(policy any) (Flags, error) {
+func Parse(policy any) (*Flags, error) {
 	if policy == nil {
 		logp.L().Debug("feature flags policy is nil, nothing to do")
-		return Flags{}, nil
+		return nil, nil
 	}
 
 	var c *config.Config
@@ -43,14 +43,14 @@ func Parse(policy any) (Flags, error) {
 		var err error
 		c, err = config.NewConfigFrom(policy)
 		if err != nil {
-			return Flags{}, fmt.Errorf("could not get a config from type %T: %w",
+			return nil, fmt.Errorf("could not get a config from type %T: %w",
 				policy, err)
 		}
 	}
 
 	if c == nil {
 		logp.L().Debug("feature flags config is nil, nothing to do")
-		return Flags{}, nil
+		return nil, nil
 	}
 
 	type cfg struct {
@@ -63,26 +63,30 @@ func Parse(policy any) (Flags, error) {
 
 	parsedFlags := cfg{}
 	if err := c.Unpack(&parsedFlags); err != nil {
-		return Flags{}, fmt.Errorf("could not umpack features config: %w", err)
+		return nil, fmt.Errorf("could not umpack features config: %w", err)
 	}
 
-	return Flags{FQDN: parsedFlags.Agent.Features.FQDN.Enabled()}, nil
+	return &Flags{FQDN: parsedFlags.Agent.Features.FQDN.Enabled()}, nil
 }
 
-// Apply receives a config and applies it. If policy is nil, Apply is a no-op.
-func Apply(c *config.Config) (Flags, error) {
+// Apply receives a config and applies it. If c is nil, Apply is a no-op.
+func Apply(c *config.Config) error {
 	if c == nil {
 		logp.L().Debug("feature flags config is nil, nothing to do")
-		return Flags{}, nil
+		return nil
 	}
 
 	var err error
 
 	mu.Lock()
 	defer mu.Unlock()
-	current, err = Parse(c) // Updating global state
+	parsed, err := Parse(c) // Updating global state
+	if err != nil {
+		return fmt.Errorf("could not apply feature flag config: %w", err)
+	}
 
-	return current, err
+	current = *parsed
+	return err
 }
 
 // FQDN reports if FQDN should be used instead of hostname for host.name.
@@ -100,7 +104,7 @@ func Current() Flags {
 	return current
 }
 
-func (f Flags) AsProto() *proto.Features {
+func (f *Flags) AsProto() *proto.Features {
 	mu.Lock()
 	defer mu.Unlock()
 	return &proto.Features{

pkg/features/features_test.go

@@ -67,7 +67,7 @@ agent:
 				t.Fatalf("could not parse config YAML: %v", err)
 			}
 
-			_, err = Apply(c)
+			err = Apply(c)
 			if err != nil {
 				t.Fatalf("Apply failed: %v", err)
 			}