backport of commit e6427b2b30 (#19620)

Co-authored-by: Tom Proctor <tomhjp@users.noreply.github.com>

changelog/19593.txt

@@ -0,0 +1,4 @@
+```release-note:improvement
+events: Suppress log warnings triggered when events are sent but the events system is not enabled.
+```
+

sdk/plugin/grpc_events.go

@@ -34,6 +34,10 @@ type GRPCEventsServer struct {
 }
 
 func (s *GRPCEventsServer) SendEvent(ctx context.Context, req *pb.SendEventRequest) (*pb.Empty, error) {
+	if s.impl == nil {
+		return &pb.Empty{}, nil
+	}
+
 	err := s.impl.Send(ctx, logical.EventType(req.EventType), req.Event)
 	if err != nil {
 		return nil, err

vault/auth.go

@@ -10,6 +10,7 @@ import (
 	"github.com/hashicorp/go-secure-stdlib/strutil"
 	"github.com/hashicorp/go-uuid"
 	"github.com/hashicorp/vault/builtin/plugin"
+	"github.com/hashicorp/vault/helper/experiments"
 	"github.com/hashicorp/vault/helper/namespace"
 	"github.com/hashicorp/vault/helper/versions"
 	"github.com/hashicorp/vault/sdk/helper/consts"
@@ -1001,12 +1002,14 @@ func (c *Core) newCredentialBackend(ctx context.Context, entry *MountEntry, sysV
 	}
 
 	config := &logical.BackendConfig{
-		StorageView:  view,
-		Logger:       authLogger,
-		Config:       conf,
-		System:       sysView,
-		BackendUUID:  entry.BackendAwareUUID,
-		EventsSender: pluginEventSender,
+		StorageView: view,
+		Logger:      authLogger,
+		Config:      conf,
+		System:      sysView,
+		BackendUUID: entry.BackendAwareUUID,
+	}
+	if c.IsExperimentEnabled(experiments.VaultExperimentEventsAlpha1) {
+		config.EventsSender = pluginEventSender
 	}
 
 	b, err := f(ctx, config)

vault/mount.go

@@ -15,6 +15,7 @@ import (
 	"github.com/hashicorp/go-secure-stdlib/strutil"
 	"github.com/hashicorp/go-uuid"
 	"github.com/hashicorp/vault/builtin/plugin"
+	"github.com/hashicorp/vault/helper/experiments"
 	"github.com/hashicorp/vault/helper/metricsutil"
 	"github.com/hashicorp/vault/helper/namespace"
 	"github.com/hashicorp/vault/helper/versions"
@@ -1660,12 +1661,14 @@ func (c *Core) newLogicalBackend(ctx context.Context, entry *MountEntry, sysView
 		return nil, "", err
 	}
 	config := &logical.BackendConfig{
-		StorageView:  view,
-		Logger:       backendLogger,
-		Config:       conf,
-		System:       sysView,
-		BackendUUID:  entry.BackendAwareUUID,
-		EventsSender: pluginEventSender,
+		StorageView: view,
+		Logger:      backendLogger,
+		Config:      conf,
+		System:      sysView,
+		BackendUUID: entry.BackendAwareUUID,
+	}
+	if c.IsExperimentEnabled(experiments.VaultExperimentEventsAlpha1) {
+		config.EventsSender = pluginEventSender
 	}
 
 	ctx = context.WithValue(ctx, "core_number", c.coreNumber)