attribute: add upstream filter state

Change-Id: I48b928db0e7b9b2d77dcafab0cbd897a7056b6ff Signed-off-by: Kuat Yessenov <[email protected]>
kyessenov · May 21, 2024 · 54cb5e5 · 54cb5e5
1 parent a112766
commit 54cb5e5
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Showing 6 changed files with 41 additions and 2 deletions.
diff --git a/docs/root/intro/arch_overview/advanced/attributes.rst b/docs/root/intro/arch_overview/advanced/attributes.rst
@@ -162,7 +162,17 @@ Data exchanged between filters is available as the following attributes:
    :widths: 1, 1, 4
 
    metadata, :ref:`Metadata<envoy_v3_api_msg_config.core.v3.metadata>`, Dynamic request metadata
-   filter_state, "map<string, bytes>", Mapping from a filter state name to its serialized string value
+   filter_state, "map<string, Value>", Mapping from the filter state name to the object value
+   upstream_filter_state, "map<string, Value>", Mapping from the upstream filter state name to the object value
+
+Filter state value representation is determined based on the filter state
+declaration in the following order:
+
+* If the value is represented as a dynamic ``CelValue`` wrapper, ``CelValue``
+  is returned verbatim.
+* If the key is well-known and has a field reflection enabled, then it is
+  returned as a map from the field names to the field values.
+* Otherwise, the value is returned as the serialized bytes.
 
 Note that these attributes may change during the life of a request as the data can be
 updated by filters at any point.

diff --git a/source/extensions/filters/common/expr/context.h b/source/extensions/filters/common/expr/context.h
@@ -52,6 +52,7 @@ constexpr absl::string_view Metadata = "metadata";
 
 // Per-request or per-connection filter state
 constexpr absl::string_view FilterState = "filter_state";
+constexpr absl::string_view UpstreamFilterState = "upstream_filter_state";
 
 // Connection properties
 constexpr absl::string_view Connection = "connection";

diff --git a/source/extensions/filters/common/expr/evaluator.cc b/source/extensions/filters/common/expr/evaluator.cc
@@ -16,7 +16,7 @@ namespace {
 
 #define ACTIVATION_TOKENS(_f)                                                                      \
   _f(Request) _f(Response) _f(Connection) _f(Upstream) _f(Source) _f(Destination) _f(Metadata)     \
-      _f(FilterState) _f(XDS)
+      _f(FilterState) _f(XDS) _f(UpstreamFilterState)
 
 #define _DECLARE(_t) _t,
 enum class ActivationToken { ACTIVATION_TOKENS(_DECLARE) };
@@ -69,6 +69,12 @@ absl::optional<CelValue> StreamActivation::FindValue(absl::string_view name,
         Protobuf::Arena::Create<FilterStateWrapper>(arena, *arena, info.filterState()));
   case ActivationToken::XDS:
     return {};
+  case ActivationToken::UpstreamFilterState:
+    if (info.upstreamInfo().has_value() &&
+        info.upstreamInfo().value().get().upstreamFilterState() != nullptr) {
+      return CelValue::CreateMap(Protobuf::Arena::Create<FilterStateWrapper>(
+          arena, *arena, *info.upstreamInfo().value().get().upstreamFilterState()));
+    }
   }
   return {};
 }

diff --git a/test/extensions/filters/common/expr/BUILD b/test/extensions/filters/common/expr/BUILD
@@ -42,6 +42,7 @@ envoy_extension_cc_test(
     tags = ["skip_on_windows"],
     deps = [
         "//source/extensions/filters/common/expr:evaluator_lib",
+        "//test/mocks/stream_info:stream_info_mocks",
         "//test/test_common:utility_lib",
         "@com_google_cel_cpp//eval/public/structs:cel_proto_wrapper",
     ],

diff --git a/test/extensions/filters/common/expr/evaluator_test.cc b/test/extensions/filters/common/expr/evaluator_test.cc
@@ -1,5 +1,6 @@
 #include "source/extensions/filters/common/expr/evaluator.h"
 
+#include "test/mocks/stream_info/mocks.h"
 #include "test/test_common/utility.h"
 
 #include "absl/time/time.h"
@@ -42,6 +43,17 @@ TEST(Evaluator, Print) {
   EXPECT_EQ(print(CelValue::CreateError(&status)), "CelError value");
 }
 
+TEST(Evaluator, Activation) {
+  NiceMock<StreamInfo::MockStreamInfo> info;
+  auto filter_state =
+      std::make_shared<StreamInfo::FilterStateImpl>(StreamInfo::FilterState::LifeSpan::FilterChain);
+  info.upstreamInfo()->setUpstreamFilterState(filter_state);
+  ProtobufWkt::Arena arena;
+  const auto activation = createActivation(nullptr, info, nullptr, nullptr, nullptr);
+  EXPECT_TRUE(activation->FindValue("filter_state", &arena).has_value());
+  EXPECT_TRUE(activation->FindValue("upstream_filter_state", &arena).has_value());
+}
+
 } // namespace
 } // namespace Expr
 } // namespace Common

diff --git a/test/integration/filters/empty.proto b/test/integration/filters/empty.proto
@@ -0,0 +1,9 @@
+syntax = "proto3";
+
+package test.integration.filters;
+
+message Backpressure {
+}
+
+message Tee {
+}