disable livedebugging by default and add a config block to enable it.…

… The stability is also updated to experimental

docs/sources/reference/config-blocks/livedebugging.md

@@ -0,0 +1,40 @@
+---
+canonical: https://grafana.com/docs/alloy/latest/reference/config-blocks/livedebugging/
+description: Learn about the livedebugging configuration block
+menuTitle: livedebugging
+title: livedebugging block
+---
+
+<span class="badge docs-labels__stage docs-labels__item">Experimental</span>
+
+# livedebugging block
+
+{{< docs/shared lookup="stability/experimental.md" source="alloy" version="<ALLOY_VERSION>" >}}
+
+`livedebugging` is an optional configuration block that enables the [live debugging feature][debug] which streams real-time data from your components directly to {{< param "PRODUCT_NAME" >}}'s UI.
+
+By default, [live debugging][debug] is disabled and must be explicitly enabled through this configuration block to make the debugging data visible in the UI.
+
+{{< admonition type="note" >}}
+Enabling this feature provides detailed insights into the data flowing through your pipelines via {{< param "PRODUCT_NAME" >}}'s API.
+To ensure that your data remains secure while live debugging is enabled, consider configuring TLS in the [http block][].
+{{< /admonition >}}
+
+## Example
+
+```alloy
+livedebugging {
+  enabled = true
+}
+```
+
+## Arguments
+
+The following arguments are supported:
+
+| Name      | Type   | Description                         | Default | Required |
+| --------- | ------ | ----------------------------------- | ------- | -------- |
+| `enabled` | `bool` | Enables the live debugging feature. | `false` | no       |
+
+[debug]: ../../../tasks/debug/
+[http block]: ../http/

internal/service/livedebugging/livedebugging.go

@@ -32,6 +32,7 @@ type liveDebugging struct {
 	loadMut   sync.RWMutex
 	callbacks map[ComponentID]map[CallbackID]func(string)
 	host      service.Host
+	enabled   bool
 }
 
 var _ CallbackManager = &liveDebugging{}
@@ -47,8 +48,10 @@ func NewLiveDebugging() *liveDebugging {
 func (s *liveDebugging) Publish(componentID ComponentID, data string) {
 	s.loadMut.RLock()
 	defer s.loadMut.RUnlock()
-	for _, callback := range s.callbacks[componentID] {
-		callback(data)
+	if s.enabled {
+		for _, callback := range s.callbacks[componentID] {
+			callback(data)
+		}
 	}
 }
 
@@ -63,6 +66,10 @@ func (s *liveDebugging) AddCallback(callbackID CallbackID, componentID Component
 	s.loadMut.Lock()
 	defer s.loadMut.Unlock()
 
+	if !s.enabled {
+		return fmt.Errorf("the live debugging service is disabled. Check the documentation to find out how to enable it")
+	}
+
 	if s.host == nil {
 		return fmt.Errorf("the live debugging service is not ready yet")
 	}
@@ -94,3 +101,9 @@ func (s *liveDebugging) SetServiceHost(h service.Host) {
 	defer s.loadMut.Unlock()
 	s.host = h
 }
+
+func (s *liveDebugging) SetEnabled(enabled bool) {
+	s.loadMut.Lock()
+	defer s.loadMut.Unlock()
+	s.enabled = enabled
+}

internal/service/livedebugging/livedebugging_test.go

@@ -15,9 +15,15 @@ func TestAddCallback(t *testing.T) {
 	callback := func(data string) {}
 
 	err := livedebugging.AddCallback(callbackID, "fake.liveDebugging", callback)
+	require.ErrorContains(t, err, "the live debugging service is disabled. Check the documentation to find out how to enable it")
+
+	livedebugging.SetEnabled(true)
+
+	err = livedebugging.AddCallback(callbackID, "fake.liveDebugging", callback)
 	require.ErrorContains(t, err, "the live debugging service is not ready yet")
 
 	setupServiceHost(livedebugging)
+
 	err = livedebugging.AddCallback(callbackID, "not found", callback)
 	require.ErrorContains(t, err, "component not found")
 
@@ -49,6 +55,10 @@ func TestStream(t *testing.T) {
 
 	livedebugging.Publish(componentID, "test data")
 	require.Equal(t, "test data", receivedData)
+
+	livedebugging.SetEnabled(false)
+	livedebugging.Publish(componentID, "new test data")
+	require.Equal(t, "test data", receivedData) // not updated because the feature is disabled
 }
 
 func TestStreamEmpty(t *testing.T) {
@@ -122,6 +132,7 @@ func setupServiceHost(liveDebugging *liveDebugging) {
 		},
 	}
 	liveDebugging.SetServiceHost(host)
+	liveDebugging.SetEnabled(true)
 }
 
 type fakeInfo struct {

internal/service/livedebugging/service.go

@@ -3,7 +3,6 @@ package livedebugging
 
 import (
 	"context"
-	"fmt"
 
 	"github.com/grafana/alloy/internal/featuregate"
 	"github.com/grafana/alloy/internal/service"
@@ -24,6 +23,10 @@ func New() *Service {
 	}
 }
 
+type Arguments struct {
+	Enabled bool `alloy:"enabled,attr,optional"`
+}
+
 // Data implements service.Service.
 // It returns the liveDebugging for the components to stream.
 func (s *Service) Data() any {
@@ -34,9 +37,9 @@ func (s *Service) Data() any {
 func (*Service) Definition() service.Definition {
 	return service.Definition{
 		Name:       ServiceName,
-		ConfigType: nil, // livedebugging does not accept configuration
+		ConfigType: Arguments{},
 		DependsOn:  []string{},
-		Stability:  featuregate.StabilityGenerallyAvailable,
+		Stability:  featuregate.StabilityExperimental,
 	}
 }
 
@@ -48,6 +51,8 @@ func (s *Service) Run(ctx context.Context, host service.Host) error {
 }
 
 // Update implements service.Service.
-func (*Service) Update(_ any) error {
-	return fmt.Errorf("livedebugging service does not support configuration")
+func (s *Service) Update(args any) error {
+	newArgs := args.(Arguments)
+	s.liveDebugging.SetEnabled(newArgs.Enabled)
+	return nil
 }