add ppl string operators (#5490)

pkg/policy/criteria/matchers.go

@@ -21,6 +21,7 @@ func matchString(dst *ast.Body, left *ast.Term, right parser.Value) error {
 	lookup := map[string]matcher{
 		"contains":    matchStringContains,
 		"ends_with":   matchStringEndsWith,
+		"not":         matchStringNot,
 		"is":          matchStringIs,
 		"starts_with": matchStringStartsWith,
 	}
@@ -47,6 +48,11 @@ func matchStringEndsWith(dst *ast.Body, left *ast.Term, right parser.Value) erro
 	return nil
 }
 
+func matchStringNot(dst *ast.Body, left *ast.Term, right parser.Value) error {
+	*dst = append(*dst, ast.NotEqual.Expr(left, ast.NewTerm(right.RegoValue())))
+	return nil
+}
+
 func matchStringIs(dst *ast.Body, left *ast.Term, right parser.Value) error {
 	*dst = append(*dst, ast.Equal.Expr(left, ast.NewTerm(right.RegoValue())))
 	return nil
@@ -66,8 +72,9 @@ func matchStringList(dst *ast.Body, left *ast.Term, right parser.Value) error {
 	}
 
 	lookup := map[string]matcher{
-		"has": matchStringListHas,
-		"is":  matchStringListIs,
+		"has":     matchStringListHas,
+		"is":      matchStringListIs,
+		"exclude": matchStringListExclude,
 	}
 	for k, v := range obj {
 		f, ok := lookup[k]
@@ -112,3 +119,24 @@ func matchStringListIs(dst *ast.Body, left *ast.Term, right parser.Value) error
 	)
 	return matchStringListHas(dst, left, right)
 }
+
+func matchStringListExclude(dst *ast.Body, left *ast.Term, right parser.Value) error {
+	body := ast.Body{
+		ast.MustParseExpr("some v"),
+		ast.Equality.Expr(ast.VarTerm("v"), ast.RefTerm(left, ast.VarTerm("$0"))),
+	}
+	err := matchStringIs(&body, ast.VarTerm("v"), right)
+	if err != nil {
+		return err
+	}
+	*dst = append(*dst, ast.Equal.Expr(
+		ast.Count.Call(
+			ast.ArrayComprehensionTerm(
+				ast.BooleanTerm(true),
+				body,
+			),
+		),
+		ast.IntNumberTerm(0),
+	))
+	return nil
+}

pkg/policy/criteria/matchers_test.go

@@ -50,6 +50,16 @@ func TestStringMatcher(t *testing.T) {
 		require.NoError(t, err)
 		assert.Equal(t, `example == "test"`, str(body))
 	})
+	t.Run("not", func(t *testing.T) {
+		t.Parallel()
+
+		var body ast.Body
+		err := matchString(&body, ast.VarTerm("example"), parser.Object{
+			"not": parser.String("test"),
+		})
+		require.NoError(t, err)
+		assert.Equal(t, `example != "test"`, str(body))
+	})
 	t.Run("starts_with", func(t *testing.T) {
 		t.Parallel()
 
@@ -118,6 +128,16 @@ func TestStringListMatcher(t *testing.T) {
 		require.NoError(t, err)
 		assert.Equal(t, `count(example) == 1`+"\n"+`count([true | some v; v = example[_]; v == "test"]) > 0`, str(body))
 	})
+	t.Run("exclude", func(t *testing.T) {
+		t.Parallel()
+
+		var body ast.Body
+		err := matchStringList(&body, ast.VarTerm("example"), parser.Object{
+			"exclude": parser.String("test"),
+		})
+		require.NoError(t, err)
+		assert.Equal(t, `count([true | some v; v = example[_]; v == "test"]) == 0`, str(body))
+	})
 	t.Run("string", func(t *testing.T) {
 		t.Parallel()