cel: support extension regex functions (#38401)

Signed-off-by: zirain <[email protected]>
envoyproxy · Feb 15, 2025 · 7cffa39 · 7cffa39
1 parent eb185a1
commit 7cffa39
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diff --git a/changelogs/current.yaml b/changelogs/current.yaml
@@ -22,6 +22,9 @@ minor_behavior_changes:
   change: |
     Ignore request_header_mode field of :ref:`mode_override <envoy_v3_api_field_service.ext_proc.v3.ProcessingResponse.mode_override>`
     when comparing the mode_override against allowed_override_modes as request_header mode override is not applicable.
+- area: cel
+  change: |
+    Support extension regex fuctions(e.g. ``re.extract``, ``re.capture`, ``re.captureN``) in CEL.
 
 bug_fixes:
 # *Changes expected to improve the state of the world and are unlikely to have negative effects*

diff --git a/source/extensions/filters/common/expr/BUILD b/source/extensions/filters/common/expr/BUILD
@@ -23,6 +23,7 @@ envoy_cc_library(
         "@com_google_cel_cpp//eval/public:cel_expr_builder_factory",
         "@com_google_cel_cpp//eval/public:cel_expression",
         "@com_google_cel_cpp//eval/public:cel_value",
+        "@com_google_cel_cpp//extensions:regex_functions",
     ],
 )
 

diff --git a/source/extensions/filters/common/expr/evaluator.cc b/source/extensions/filters/common/expr/evaluator.cc
@@ -3,6 +3,8 @@
 #include "envoy/common/exception.h"
 #include "envoy/singleton/manager.h"
 
+#include "extensions/regex_functions.h"
+
 #include "eval/public/builtin_func_registrar.h"
 #include "eval/public/cel_expr_builder_factory.h"
 
@@ -104,6 +106,7 @@ BuilderPtr createBuilder(Protobuf::Arena* arena) {
   options.enable_comprehension = false;
   options.enable_regex = true;
   options.regex_max_program_size = 100;
+  options.enable_qualified_identifier_rewrites = true;
   options.enable_string_conversion = false;
   options.enable_string_concat = false;
   options.enable_list_concat = false;
@@ -121,6 +124,12 @@ BuilderPtr createBuilder(Protobuf::Arena* arena) {
     throw CelException(
         absl::StrCat("failed to register built-in functions: ", register_status.message()));
   }
+  auto ext_register_status =
+      cel::extensions::RegisterRegexFunctions(builder->GetRegistry(), options);
+  if (!ext_register_status.ok()) {
+    throw CelException(absl::StrCat("failed to register extension regex functions: ",
+                                    ext_register_status.message()));
+  }
   return builder;
 }
 

diff --git a/test/extensions/formatter/cel/cel_test.cc b/test/extensions/formatter/cel/cel_test.cc
@@ -177,6 +177,22 @@ TEST_F(CELFormatterTest, TestInvalidExpression) {
       *Envoy::Formatter::SubstitutionFormatStringUtils::fromProtoConfig(config_, context_),
       EnvoyException, "Not able to parse filter expression: .*");
 }
+
+TEST_F(CELFormatterTest, TestRegexExtFunctions) {
+  const std::string yaml = R"EOF(
+  text_format_source:
+    inline_string: "%CEL(request.url_path.contains('request'))% %CEL(re.extract('', '', ''))%"
+  formatters:
+    - name: envoy.formatter.cel
+      typed_config:
+        "@type": type.googleapis.com/envoy.extensions.formatter.cel.v3.Cel
+)EOF";
+  TestUtility::loadFromYaml(yaml, config_);
+
+  auto formatter =
+      *Envoy::Formatter::SubstitutionFormatStringUtils::fromProtoConfig(config_, context_);
+  EXPECT_EQ("true ", formatter->formatWithContext(formatter_context_, stream_info_));
+}
 #endif
 
 } // namespace Formatter