[ProtoApiScrubber] Add directory skeleton and basic logic for field checker

source/extensions/filters/http/proto_api_scrubber/scrubbing_util_lib/BUILD

@@ -0,0 +1,23 @@
+load(
+    "//bazel:envoy_build_system.bzl",
+    "envoy_cc_library",
+    "envoy_extension_package",
+)
+
+licenses(["notice"])  # Apache 2
+
+envoy_extension_package()
+
+envoy_cc_library(
+    name = "scrubbing_util_lib",
+    srcs = [
+        "field_checker.cc",
+    ],
+    hdrs = [
+        "field_checker.h",
+    ],
+    deps = [
+        "//source/common/protobuf",
+        "@com_google_protoprocessinglib//proto_processing_lib/proto_scrubber",
+    ],
+)

source/extensions/filters/http/proto_api_scrubber/scrubbing_util_lib/field_checker.cc

@@ -0,0 +1,24 @@
+#include "source/extensions/filters/http/proto_api_scrubber/scrubbing_util_lib/field_checker.h"
+
+#include "source/common/protobuf/protobuf.h"
+
+#include "proto_processing_lib/proto_scrubber/field_checker_interface.h"
+
+namespace Envoy {
+namespace Extensions {
+namespace HttpFilters {
+namespace ProtoApiScrubber {
+
+FieldCheckResults FieldChecker::CheckField(const std::vector<std::string>&,
+                                           const Protobuf::Field*) const {
+  return FieldCheckResults::kInclude;
+}
+
+FieldCheckResults FieldChecker::CheckType(const Protobuf::Type*) const {
+  return FieldCheckResults::kInclude;
+}
+
+} // namespace ProtoApiScrubber
+} // namespace HttpFilters
+} // namespace Extensions
+} // namespace Envoy

source/extensions/filters/http/proto_api_scrubber/scrubbing_util_lib/field_checker.h

@@ -0,0 +1,60 @@
+#pragma once
+
+#include <string>
+#include <vector>
+
+#include "source/common/protobuf/protobuf.h"
+
+#include "proto_processing_lib/proto_scrubber/field_checker_interface.h"
+
+namespace Envoy {
+namespace Extensions {
+namespace HttpFilters {
+namespace ProtoApiScrubber {
+
+using proto_processing_lib::proto_scrubber::FieldCheckerInterface;
+using proto_processing_lib::proto_scrubber::FieldCheckResults;
+using proto_processing_lib::proto_scrubber::FieldFilters;
+
+/**
+ * FieldChecker class encapsulates the scrubbing logic of `ProtoApiScrubber` filter.
+ * This `FieldChecker` would be integrated with `proto_processing_lib::proto_scrubber` library for
+ * protobuf payload scrubbing. The `CheckField()` method declared in the parent class
+ * `FieldCheckerInterface` and defined in this class is called by the
+ * `proto_processing_lib::proto_scrubber` library for each field of the protobuf payload to decide
+ * whether to preserve, remove or traverse it further.
+ */
+class FieldChecker : public FieldCheckerInterface {
+public:
+  FieldChecker() {}
+
+  // This type is neither copyable nor movable.
+  FieldChecker(const FieldChecker&) = delete;
+  FieldChecker& operator=(const FieldChecker&) = delete;
+  ~FieldChecker() override {}
+
+  /**
+   * Returns whether the `field` should be included (kInclude), excluded (kExclude)
+   * or traversed further (kPartial).
+   */
+  FieldCheckResults CheckField(const std::vector<std::string>& path,
+                               const Protobuf::Field* field) const override;
+
+  /**
+   * Returns false as it currently doesn't support `google.protobuf.Any` type.
+   */
+  bool SupportAny() const override { return false; }
+
+  /**
+   * Returns whether the `type` should be included (kInclude), excluded (kExclude)
+   * or traversed further (kPartial).
+   */
+  FieldCheckResults CheckType(const Protobuf::Type* type) const override;
+
+  FieldFilters FilterName() const override { return FieldFilters::FieldMaskFilter; }
+};
+
+} // namespace ProtoApiScrubber
+} // namespace HttpFilters
+} // namespace Extensions
+} // namespace Envoy

test/extensions/filters/http/proto_api_scrubber/scrubbing_util_lib/BUILD

@@ -0,0 +1,21 @@
+load(
+    "//bazel:envoy_build_system.bzl",
+    "envoy_cc_test",
+    "envoy_package",
+)
+
+licenses(["notice"])  # Apache 2
+
+envoy_package()
+
+envoy_cc_test(
+    name = "field_checker_test",
+    srcs = ["field_checker_test.cc"],
+    deps = [
+        "//source/common/protobuf",
+        "//source/extensions/filters/http/proto_api_scrubber/scrubbing_util_lib",
+        "//test/test_common:environment_lib",
+        "//test/test_common:utility_lib",
+        "@com_google_protoprocessinglib//proto_processing_lib/proto_scrubber",
+    ],
+)

test/extensions/filters/http/proto_api_scrubber/scrubbing_util_lib/field_checker_test.cc

@@ -0,0 +1,51 @@
+#include "source/common/protobuf/protobuf.h"
+#include "source/extensions/filters/http/proto_api_scrubber/scrubbing_util_lib/field_checker.h"
+
+#include "test/test_common/utility.h"
+
+#include "gtest/gtest.h"
+#include "proto_processing_lib/proto_scrubber/field_checker_interface.h"
+
+using proto_processing_lib::proto_scrubber::FieldCheckResults;
+using proto_processing_lib::proto_scrubber::FieldFilters;
+
+namespace Envoy {
+namespace Extensions {
+namespace HttpFilters {
+namespace ProtoApiScrubber {
+namespace {
+
+class FieldCheckerTest : public ::testing::Test {};
+
+// With the current basic implementation, all fields are included. This test
+// verifies that behavior for a few different field paths. Once field mask
+// logic is added, this test suite should be expanded to cover exclusion,
+// wildcards, and other scenarios.
+TEST_F(FieldCheckerTest, IncludesSimpleField) {
+  FieldChecker field_checker;
+  Protobuf::Field simple_field;
+  simple_field.set_name("name");
+  EXPECT_EQ(field_checker.CheckField({"name"}, &simple_field), FieldCheckResults::kInclude);
+}
+
+TEST_F(FieldCheckerTest, IncludesType) {
+  FieldChecker field_checker;
+  Protobuf::Type type;
+  EXPECT_EQ(field_checker.CheckType(&type), FieldCheckResults::kInclude);
+}
+
+TEST_F(FieldCheckerTest, SupportAny) {
+  FieldChecker field_checker;
+  EXPECT_FALSE(field_checker.SupportAny());
+}
+
+TEST_F(FieldCheckerTest, FilterName) {
+  FieldChecker field_checker;
+  EXPECT_EQ(field_checker.FilterName(), FieldFilters::FieldMaskFilter);
+}
+
+} // namespace
+} // namespace ProtoApiScrubber
+} // namespace HttpFilters
+} // namespace Extensions
+} // namespace Envoy