Add the filename to Rego fragment locations.

pkg/doc/fragment.go

@@ -18,7 +18,6 @@ import (
 	"bytes"
 	"errors"
 	"fmt"
-	"io"
 
 	"github.com/projectcontour/integration-tester/pkg/utils"
 
@@ -79,6 +78,10 @@ func (t FragmentType) String() string {
 
 // Location tracks the lines that bound a Fragment within some larger Document.
 type Location struct {
+	// Filename is the name of the file this Fragment was read from
+	// (if that is known by the fragment reader).
+	Filename string
+
 	// Start is the line number this location starts on.
 	Start int
 
@@ -87,6 +90,10 @@ type Location struct {
 }
 
 func (l Location) String() string {
+	if l.Filename != "" {
+		return fmt.Sprintf("%s:%d-%d", l.Filename, l.Start, l.End)
+	}
+
 	return fmt.Sprintf("%d-%d", l.Start, l.End)
 }
 
@@ -153,20 +160,6 @@ func decodeYAMLOrJSON(data []byte) (*unstructured.Unstructured, error) {
 	return &unstructured.Unstructured{Object: into}, nil
 }
 
-func decodeModule(data []byte) (*ast.Module, error) {
-	m, err := utils.ParseCheckFragment(string(data))
-	if err != nil {
-		return nil, err
-	}
-
-	// ParseModule can return nil with no error (empty module).
-	if m == nil {
-		return nil, io.EOF
-	}
-
-	return m, nil
-}
-
 // IsDecoded returns whether this fragment has been decoded to a known fragment type.
 func (f *Fragment) IsDecoded() bool {
 	switch f.Type {
@@ -208,7 +201,7 @@ func (f *Fragment) Decode() (FragmentType, error) {
 	// Since we do want to propagate errors so that users can debug
 	// scripts, we have to assume this is meant to be Rego.
 
-	m, err := decodeModule(f.Bytes)
+	m, err := utils.ParseCheckFragment(f.Location.String(), string(f.Bytes))
 	if err != nil {
 		return FragmentTypeInvalid,
 			utils.ChainErrors(

pkg/doc/read.go

@@ -35,6 +35,7 @@ type Document struct {
 // YAML document separator (see https://yaml.org/spec/1.0/#id2561718).
 // The contents of each Fragment is opaque and need not be YAML.
 func ReadDocument(in io.Reader) (*Document, error) {
+	filename := ""
 	startLine := 0
 	currentLine := 0
 
@@ -45,6 +46,10 @@ func ReadDocument(in io.Reader) (*Document, error) {
 
 	scanner := bufio.NewScanner(in)
 
+	if f, ok := in.(*os.File); ok {
+		filename = f.Name()
+	}
+
 	// Scan the input a line at a time.
 	for scanner.Scan() {
 		currentLine++
@@ -66,8 +71,9 @@ func ReadDocument(in io.Reader) (*Document, error) {
 				doc.Parts = append(doc.Parts, Fragment{
 					Bytes: utils.CopyBytes(buf.Bytes()),
 					Location: Location{
-						Start: startLine,
-						End:   currentLine - 1,
+						Filename: filename,
+						Start:    startLine,
+						End:      currentLine - 1,
 					},
 				})
 			}
@@ -85,8 +91,9 @@ func ReadDocument(in io.Reader) (*Document, error) {
 		doc.Parts = append(doc.Parts, Fragment{
 			Bytes: utils.CopyBytes(buf.Bytes()),
 			Location: Location{
-				Start: startLine,
-				End:   currentLine,
+				Filename: filename,
+				Start:    startLine,
+				End:      currentLine,
 			},
 		})
 	}

pkg/utils/policy.go

@@ -43,15 +43,20 @@ func ParseModuleFile(filePath string) (*ast.Module, error) {
 // Rego input is assumed to not have a package declaration so a random
 // package name is prepended to make the parsed module globally unique.
 // ParseCheckFragment can return nil with no error if the input is empty.
-func ParseCheckFragment(input string) (*ast.Module, error) {
+// If the filename parameter is empty, an internal name will be generated.
+func ParseCheckFragment(filename string, input string) (*ast.Module, error) {
 	// Rego requires a package name to generate any Rules.  Force
 	// a package name that is unique to the fragment.  Note that
 	// we also use this to generate a unique filename placeholder
 	// since Rego internals will sometime use this as a map key.
 	moduleName := RandomStringN(12)
 
+	if filename == "" {
+		filename = fmt.Sprintf("internal/check/%s", moduleName)
+	}
+
 	m, err := ast.ParseModule(
-		fmt.Sprintf("internal/check/%s", moduleName),
+		filename,
 		fmt.Sprintf("package check.%s\n%s", moduleName, input))
 	if err != nil {
 		return nil, err