rework interfaces for runner change detection

cmd/launcher/launcher.go

@@ -373,7 +373,7 @@ func runLauncher(ctx context.Context, cancel func(), multiSlogger, systemMultiSl
 		osqueryruntime.WithAugeasLensFunction(augeas.InstallLenses),
 	)
 	runGroup.Add("osqueryRunner", osqueryRunner.Run, osqueryRunner.Interrupt)
-	k.SetInstanceQuerier(osqueryRunner)
+	k.SetInstanceRunner(osqueryRunner)
 
 	versionInfo := version.Version()
 	k.SystemSlogger().Log(ctx, slog.LevelInfo,

ee/agent/knapsack/knapsack.go

@@ -39,7 +39,7 @@ type knapsack struct {
 
 	slogger, systemSlogger *multislogger.MultiSlogger
 
-	querier types.InstanceQuerier
+	osqRunner types.OsqRunner
 
 	// This struct is a work in progress, and will be iteratively added to as needs arise.
 }
@@ -87,23 +87,31 @@ func (k *knapsack) AddSlogHandler(handler ...slog.Handler) {
 	k.systemSlogger.AddHandler(handler...)
 }
 
-// Osquery instance querier
-func (k *knapsack) SetInstanceQuerier(q types.InstanceQuerier) {
-	k.querier = q
+// Osquery instance runner
+func (k *knapsack) SetInstanceRunner(r types.OsqRunner) {
+	k.osqRunner = r
 }
 
 // RegistrationTracker interface methods
 func (k *knapsack) RegistrationIDs() []string {
 	return []string{types.DefaultRegistrationID}
 }
 
+func (k *knapsack) SetRegistrationIDs(registrationIDs []string) error {
+	if k.osqRunner == nil {
+		return nil
+	}
+
+	return k.osqRunner.UpdateRegistrationIDs(registrationIDs)
+}
+
 // InstanceStatuses returns the current status of each osquery instance.
 // It performs a healthcheck against each existing instance.
 func (k *knapsack) InstanceStatuses() map[string]types.InstanceStatus {
-	if k.querier == nil {
+	if k.osqRunner == nil {
 		return nil
 	}
-	return k.querier.InstanceStatuses()
+	return k.osqRunner.InstanceStatuses()
 }
 
 // BboltDB interface methods

ee/agent/types/knapsack.go

@@ -11,7 +11,7 @@ type Knapsack interface {
 	Slogger
 	RegistrationTracker
 	InstanceQuerier
-	SetInstanceQuerier(q InstanceQuerier)
+	SetInstanceRunner(r OsqRunner)
 	// LatestOsquerydPath finds the path to the latest osqueryd binary, after accounting for updates.
 	LatestOsquerydPath(ctx context.Context) string
 	// ReadEnrollSecret returns the enroll secret value, checking in various locations.

ee/agent/types/registration.go

@@ -9,4 +9,5 @@ const (
 // data may be provided by e.g. a control server subsystem.
 type RegistrationTracker interface {
 	RegistrationIDs() []string
-}
+	SetRegistrationIDs(registrationIDs []string) error
+}

ee/agent/types/runner.go

@@ -0,0 +1,13 @@
+package types
+
+type (
+	// RegistrationChangeHandler is implemented by pkg/osquery/runtime/runner.go
+	RegistrationChangeHandler interface {
+		UpdateRegistrationIDs(registrationIDs []string) error
+	}
+
+	OsqRunner interface {
+		RegistrationChangeHandler
+		InstanceQuerier
+	}
+)

pkg/osquery/runtime/runner.go

@@ -333,3 +333,8 @@ func (r *Runner) InstanceStatuses() map[string]types.InstanceStatus {
 
 	return instanceStatuses
 }
+
+func (r *Runner) UpdateRegistrationIDs(registrationIDs []string) error {
+	// TODO: detect any difference in reg IDs and shut down/spin up instances accordingly
+	return nil
+}