feat: include metrics about number of custom rules

internal/build.go

@@ -3,8 +3,10 @@ package internal
 import (
 	"bytes"
 	"context"
+	"fmt"
 	"io"
 	"os"
+	"path"
 	"strings"
 
 	"github.com/open-policy-agent/opa/ast"
@@ -30,6 +32,19 @@ type BuildCommandParams struct {
 func RunBuild(args []string, params *BuildCommandParams) error {
 	buf := bytes.NewBuffer(nil)
 
+	var metadataFile = ""
+	rules, err := util.RetrieveRules(args)
+	if err == nil {
+		// choose either one of the locations for the metadata.json
+		// it will be included in the OPA generated data.json
+		metadataFile = path.Join(args[0], "metadata.json")
+		err = os.WriteFile(metadataFile, []byte(fmt.Sprintf("{\"numberOfRules\": %d}", len(rules))),
+			0644)
+		if err != nil {
+			return err
+		}
+	}
+
 	var capabilities *ast.Capabilities
 	// if capabilities are not provided as a cmd flag,
 	// then ast.CapabilitiesForThisVersion must be called
@@ -49,7 +64,7 @@ func RunBuild(args []string, params *BuildCommandParams) error {
 		WithPaths(args...).
 		WithFilter(buildCommandLoaderFilter(false, params.Ignore))
 
-	err := compiler.Build(context.Background())
+	err = compiler.Build(context.Background())
 	if err != nil {
 		return err
 	}
@@ -64,6 +79,10 @@ func RunBuild(args []string, params *BuildCommandParams) error {
 		return err
 	}
 
+	if metadataFile != "" {
+		_ = os.Remove(metadataFile)
+	}
+
 	return out.Close()
 }
 

internal/build_test.go

@@ -2,6 +2,7 @@ package internal
 
 import (
 	"archive/tar"
+	"bytes"
 	"compress/gzip"
 	"io"
 	"os"
@@ -268,3 +269,57 @@ func TestBuildRespectsCapabilitiesFailure(t *testing.T) {
 		assert.Contains(t, err.Error(), "undefined function is_foo")
 	})
 }
+
+func TestBuildProducesMetadata(t *testing.T) {
+	files := map[string]string{
+		"test.rego": `
+			package test
+			msg = {
+				"publicId":
+					"1"
+			}
+		`,
+	}
+
+	test.WithTempFS(files, func(root string) {
+		buildParams := mockBuildParams()
+		buildParams.OutputFile = path.Join(root, "bundle.tar.gz")
+		err := buildParams.Target.Set(TargetRego)
+		assert.Nil(t, err)
+
+		err = RunBuild([]string{root}, buildParams)
+		assert.Nil(t, err)
+
+		_, err = loader.NewFileLoader().AsBundle(buildParams.OutputFile)
+		assert.Nil(t, err)
+
+		// Check that manifest is not written given no input manifest and no other flags
+		f, err := os.Open(buildParams.OutputFile)
+		assert.Nil(t, err)
+		defer f.Close()
+
+		gr, err := gzip.NewReader(f)
+		assert.Nil(t, err)
+
+		tr := tar.NewReader(gr)
+
+		for {
+			f, err := tr.Next()
+			if err == io.EOF {
+				break
+			}
+			assert.Nil(t, err)
+
+			if f.Name == "/data.json" {
+				data := new(bytes.Buffer)
+				_, err := data.ReadFrom(tr)
+				assert.Nil(t, err)
+				assert.Contains(t, data.String(), "{\"numberOfRules\":1}")
+			}
+
+			if f.Name == "/metadata.json" {
+				t.Fatal("unexpected file:", f.Name)
+			}
+		}
+	})
+}

util/inspect.go

@@ -0,0 +1,55 @@
+package util
+
+import (
+	"github.com/open-policy-agent/opa/loader"
+	"os"
+	"path/filepath"
+	"regexp"
+	"strings"
+)
+
+func RetrieveRules(path string) ([]string, error) {
+	result, err := loader.AllRegos([]string{path})
+	if err != nil {
+		return nil, err
+	}
+
+	fileNames := []string{}
+	for _, module := range result.Modules {
+		fileName := filepath.Clean(module.Name)
+		if !strings.Contains(fileName, "_test.rego") {
+			fileNames = append(fileNames, fileName)
+		}
+	}
+
+	var publicIds = []string{}
+	for _, fileName := range fileNames {
+		publicId, err := getPublicIdFromFile(fileName)
+		if err != nil {
+			return []string{}, err
+		}
+		if publicId != "" {
+			publicIds = append(publicIds, publicId)
+		}
+	}
+	return publicIds, nil
+}
+
+func getPublicIdFromFile(fileName string) (string, error) {
+	data, err := os.ReadFile(fileName)
+	if err != nil {
+		return "", err
+	}
+
+	publicId := extractPublicIdFromRego(string(data))
+	return publicId, nil
+}
+
+func extractPublicIdFromRego(rego string) string {
+	re := regexp.MustCompile("\"publicId\"\\s*:\\s*\"(.*?)\"")
+	match := re.FindStringSubmatch(rego)
+	if len(match) > 0 {
+		return match[1]
+	}
+	return ""
+}

util/inspect_test.go

@@ -0,0 +1,88 @@
+package util
+
+import (
+	"github.com/open-policy-agent/opa/util/test"
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestRetrieveRulesWitInvalidPath(t *testing.T) {
+	_, err := RetrieveRules("./invalid")
+	assert.NotNil(t, err)
+	assert.Contains(t, err.Error(), "./invalid: no such file or directory")
+}
+
+func TestRetrieveRulesWithNoFiles(t *testing.T) {
+	files := map[string]string{}
+	test.WithTempFS(files, func(root string) {
+		rules, err := RetrieveRules(root)
+		assert.Nil(t, err)
+		assert.Equal(t, 0, len(rules))
+	})
+}
+
+func TestRetrieveRulesWithNoRules(t *testing.T) {
+	files := map[string]string{
+		"test.json": `
+			test
+		`,
+	}
+
+	test.WithTempFS(files, func(root string) {
+		rules, err := RetrieveRules(root)
+		assert.Nil(t, err)
+		assert.Equal(t, 0, len(rules))
+	})
+}
+
+func TestRetrieveRulesWithRulesWithoutPublicId(t *testing.T) {
+	files := map[string]string{
+		"test.rego": `
+			package test
+			msg = {
+				"publicI":
+					"1"
+			}
+		`,
+	}
+
+	test.WithTempFS(files, func(root string) {
+		rules, err := RetrieveRules(root)
+		assert.Nil(t, err)
+		assert.Equal(t, 0, len(rules))
+	})
+}
+
+func TestRetrieveRulesWithRulesWithPublicId(t *testing.T) {
+	files := map[string]string{
+		"test1.rego": `
+			package test
+			msg = {
+				"publicId":
+					"1"
+			}
+		`,
+		"test2.rego": `
+			package test
+			msg = {
+				"publicId":
+					"2"
+			}
+		`,
+		"test2_test.rego": `
+			package test
+			msg = {
+				"publicId":
+					"3"
+			}
+		`,
+	}
+
+	test.WithTempFS(files, func(root string) {
+		rules, err := RetrieveRules(root)
+		assert.Nil(t, err)
+		assert.Equal(t, 2, len(rules))
+		assert.Equal(t, "1", rules[0])
+		assert.Equal(t, "2", rules[1])
+	})
+}