tools: Avoid picking protoc file randomly

The list of protogen.File passed to tetragon plugin might contain 3rd
party files from the import statement as well. For example, if bpf.proto
imports google/protobuf/duration.proto, then generated file will be in
v1/google/protobuf instead of v1/tetragon directory.

This commit is to make sure the location is correctly derived.

Signed-off-by: Tam Mach <[email protected]>

Author: sayboras

tools/protoc-gen-go-tetragon/common/common.go

@@ -14,6 +14,8 @@ import (
 	"google.golang.org/protobuf/reflect/protoreflect"
 )
 
+var TetragonProtoPackageName = "tetragon"
+
 // TetragonPackageName is the import path for the Tetragon package
 var TetragonPackageName = "github.com/cilium/tetragon"
 
@@ -366,3 +368,14 @@ func GetEnums(files []*protogen.File) ([]*protogen.Enum, error) {
 
 	return enumsCache, nil
 }
+
+// GetFirstTetragonFile returns the first file in the provided files that has a filename prefix
+// starting with TetragonProtoPackageName
+func GetFirstTetragonFile(files []*protogen.File) (*protogen.File, error) {
+	for _, file := range files {
+		if strings.HasPrefix(file.GeneratedFilenamePrefix, TetragonProtoPackageName) {
+			return file, nil
+		}
+	}
+	return nil, errors.New("no Tetragon file found in the provided files")
+}

tools/protoc-gen-go-tetragon/eventchecker/eventchecker.go

@@ -14,8 +14,12 @@ func Generate(gen *protogen.Plugin, files []*protogen.File) error {
 	// generated files will be in pkg tetragon so its not important
 	// from packaging side and any prefix will work fine we just pick
 	// the first file arbitrarily.
-	g := common.NewCodegenFile(gen, files[0], "eventchecker")
-	yaml := common.NewCodegenFile(gen, files[0], "eventchecker/yaml")
+	f, err := common.GetFirstTetragonFile(files)
+	if err != nil {
+		return err
+	}
+	g := common.NewCodegenFile(gen, f, "eventchecker")
+	yaml := common.NewCodegenFile(gen, f, "eventchecker/yaml")
 
 	if err := generateEventCheckerConf(yaml); err != nil {
 		return err

tools/protoc-gen-go-tetragon/helpers/helpers.go

@@ -298,8 +298,11 @@ func generateProcessEventMap(g *protogen.GeneratedFile, files []*protogen.File)
 
 // Generate generates boilerplate helpers
 func Generate(gen *protogen.Plugin, files []*protogen.File) error {
-	// Pick arbitrary file to use for prefix of generated files, files[0] here.
-	g := common.NewCodegenFile(gen, files[0], "helpers")
+	f, err := common.GetFirstTetragonFile(files)
+	if err != nil {
+		return err
+	}
+	g := common.NewCodegenFile(gen, f, "helpers")
 
 	if err := generateResponseTypeString(g, files); err != nil {
 		return err

tools/protoc-gen-go-tetragon/types/types.go

@@ -11,7 +11,11 @@ import (
 )
 
 func Generate(gen *protogen.Plugin, files []*protogen.File) error {
-	g := common.NewFile(gen, files[0], "", filepath.Base(common.TetragonApiPackageName), "types")
+	f, err := common.GetFirstTetragonFile(files)
+	if err != nil {
+		return err
+	}
+	g := common.NewFile(gen, f, "", filepath.Base(common.TetragonApiPackageName), "types")
 
 	events, err := common.GetEvents(files)
 	if err != nil {