tetragon: Plug in the config object

Adding --config-file option that allows to start tetragon
with config file using the config object.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>

cmd/tetragon/main.go

@@ -28,6 +28,7 @@ import (
 	"github.com/cilium/tetragon/pkg/bugtool"
 	"github.com/cilium/tetragon/pkg/checkprocfs"
 	"github.com/cilium/tetragon/pkg/cilium"
+	"github.com/cilium/tetragon/pkg/config"
 	"github.com/cilium/tetragon/pkg/defaults"
 	"github.com/cilium/tetragon/pkg/encoder"
 	"github.com/cilium/tetragon/pkg/exporter"
@@ -436,6 +437,12 @@ func tetragonExecute() error {
 		base.Unload()
 	}()
 
+	cfg := config.NewConfig(option.Config.ConfigFile, 5*time.Second,
+		func(_ uint64, spec config.Spec) {
+			config.OptionsReconfig(spec)
+		})
+	defer cfg.Stop()
+
 	// now that the base sensor was loaded, we can start the sensor manager
 	close(sensorMgWait)
 	sensorMgWait = nil

pkg/config/options.go

@@ -0,0 +1,12 @@
+// SPDX-License-Identifier: Apache-2.0
+// Copyright Authors of Tetragon
+
+package config
+
+import "github.com/cilium/tetragon/pkg/option"
+
+func OptionsReconfig(spec Spec) {
+	if spec.Options.DisableKprobeMulti != nil {
+		option.Config.DisableKprobeMulti = *spec.Options.DisableKprobeMulti
+	}
+}

pkg/option/config.go

@@ -86,6 +86,8 @@ type config struct {
 	EnableTracingPolicyCRD bool
 
 	ExposeKernelAddresses bool
+
+	ConfigFile string
 }
 
 var (

pkg/option/flags.go

@@ -92,6 +92,8 @@ const (
 	KeyExposeKernelAddresses = "expose-kernel-addresses"
 
 	KeyGenerateDocs = "generate-docs"
+
+	KeyConfigFile = "config-file"
 )
 
 func ReadAndSetFlags() error {
@@ -172,6 +174,7 @@ func ReadAndSetFlags() error {
 
 	Config.ExposeKernelAddresses = viper.GetBool(KeyExposeKernelAddresses)
 
+	Config.ConfigFile = viper.GetString(KeyConfigFile)
 	return nil
 }
 
@@ -278,4 +281,6 @@ func AddFlags(flags *pflag.FlagSet) {
 	flags.Bool(KeyExposeKernelAddresses, false, "Expose real kernel addresses in events stack traces")
 
 	flags.Bool(KeyGenerateDocs, false, "Generate documentation in YAML format to stdout")
+
+	flags.String(KeyConfigFile, "", "configuration file")
 }