cgidimap: skip warning if cgidmap is disabled

Currently, if cgidmap is disabled (this is the default), the agent
issues the following warning:

level=warning msg="failed to retrieve cgidmap, not registering rthook" error="cgidmap disabled"

This commit changes the message to indicate that this actually happens
in the podhook and, also, does not emit a warning if the error is that
cgidmap is disabled.

Signed-off-by: Kornilios Kourtis <[email protected]>

pkg/cgidmap/cgidmap.go

@@ -8,7 +8,6 @@
 package cgidmap
 
 import (
-	"errors"
 	"sync"
 
 	"github.com/cilium/tetragon/pkg/logger"
@@ -249,12 +248,20 @@ var (
 	setGlMap sync.Once
 )
 
+type cgidDisabledTy struct{}
+
+var cgidDisabled = &cgidDisabledTy{}
+
+func (e *cgidDisabledTy) Error() string {
+	return "cgidmap disabled"
+}
+
 // GetState returns the global map
 func GlobalMap() (Map, error) {
 	setGlMap.Do(func() {
 		if !option.Config.EnableCgIDmap {
 			glMap = nil
-			glError = errors.New("cgidmap disabled")
+			glError = cgidDisabled
 			return
 		}
 

pkg/cgidmap/podhooks.go

@@ -4,6 +4,8 @@
 package cgidmap
 
 import (
+	"errors"
+
 	"github.com/cilium/tetragon/pkg/logger"
 	"github.com/cilium/tetragon/pkg/podhelpers"
 	"github.com/cilium/tetragon/pkg/podhooks"
@@ -26,7 +28,10 @@ func registerPodCallbacks(podInformer cache.SharedIndexInformer) {
 
 	m, err := GlobalMap()
 	if err != nil {
-		logger.GetLogger().WithError(err).Warn("failed to retrieve cgidmap, not registering rthook")
+		// if cgidmap is disabled, an error is expected so do not omit a warning
+		if !errors.Is(err, cgidDisabled) {
+			logger.GetLogger().WithError(err).Warn("failed to retrieve cgidmap, not registering podhook")
+		}
 		return
 	}