gzip filter: allow setting zlib compressor's chunk size (#10508)

Signed-off-by: Raul Gutierrez Segales <rgs@pinterest.com>

api/envoy/extensions/filters/http/gzip/v3/gzip.proto

@@ -19,7 +19,7 @@ option (udpa.annotations.file_status).package_version_status = ACTIVE;
 // Gzip :ref:`configuration overview <config_http_filters_gzip>`.
 // [#extension: envoy.filters.http.gzip]
 
-// [#next-free-field: 11]
+// [#next-free-field: 12]
 message Gzip {
   option (udpa.annotations.versioning).previous_message_type =
       "envoy.config.filter.http.gzip.v2.Gzip";
@@ -76,4 +76,9 @@ message Gzip {
   // the fields `content_length`, `content_type`, `disable_on_etag_header` and
   // `remove_accept_encoding_header` are ignored.
   compressor.v3.Compressor compressor = 10;
+
+  // Value for Zlib's next output buffer. If not set, defaults to 4096.
+  // See https://www.zlib.net/manual.html for more details. Also see
+  // https://github.com/envoyproxy/envoy/issues/8448 for context on this filter's performance.
+  google.protobuf.UInt32Value chunk_size = 11 [(validate.rules).uint32 = {lte: 65536 gte: 4096}];
 }

docs/root/version_history/current.rst

@@ -13,6 +13,7 @@ Changes
   Disabled by default and can be enabled via :ref:`enable_upstream_stats <envoy_v3_api_field_extensions.filters.http.grpc_stats.v3.FilterConfig.enable_upstream_stats>`.
 * grpc-json: added support for streaming response using
   `google.api.HttpBody <https://github.com/googleapis/googleapis/blob/master/google/api/httpbody.proto>`_.
+* gzip filter: added option to set zlib's next output buffer size.
 * http: fixed a bug where in some cases slash was moved from path to query string when :ref:`merging of adjacent slashes<envoy_api_field_config.filter.network.http_connection_manager.v2.HttpConnectionManager.merge_slashes>` is enabled.
 * http: fixed a bug where the upgrade header was not cleared on responses to non-upgrade requests.
   Can be reverted temporarily by setting runtime feature `envoy.reloadable_features.fix_upgrade_response` to false.

source/extensions/filters/http/gzip/gzip_filter.cc

@@ -28,10 +28,11 @@ GzipFilterConfig::GzipFilterConfig(const envoy::extensions::filters::http::gzip:
       compression_level_(compressionLevelEnum(gzip.compression_level())),
       compression_strategy_(compressionStrategyEnum(gzip.compression_strategy())),
       memory_level_(memoryLevelUint(gzip.memory_level().value())),
-      window_bits_(windowBitsUint(gzip.window_bits().value())) {}
+      window_bits_(windowBitsUint(gzip.window_bits().value())),
+      chunk_size_(PROTOBUF_GET_WRAPPED_OR_DEFAULT(gzip, chunk_size, 4096)) {}
 
 std::unique_ptr<Compressor::Compressor> GzipFilterConfig::makeCompressor() {
-  auto compressor = std::make_unique<Compressor::ZlibCompressorImpl>();
+  auto compressor = std::make_unique<Compressor::ZlibCompressorImpl>(chunk_size_);
   compressor->init(compressionLevel(), compressionStrategy(), windowBits(), memoryLevel());
   return compressor;
 }

source/extensions/filters/http/gzip/gzip_filter.h

@@ -31,6 +31,7 @@ class GzipFilterConfig : public Common::Compressors::CompressorFilterConfig {
 
   uint64_t memoryLevel() const { return memory_level_; }
   uint64_t windowBits() const { return window_bits_; }
+  uint32_t chunkSize() const { return chunk_size_; }
 
 private:
   static Compressor::ZlibCompressorImpl::CompressionLevel compressionLevelEnum(
@@ -48,8 +49,9 @@ class GzipFilterConfig : public Common::Compressors::CompressorFilterConfig {
   Compressor::ZlibCompressorImpl::CompressionLevel compression_level_;
   Compressor::ZlibCompressorImpl::CompressionStrategy compression_strategy_;
 
-  int32_t memory_level_;
-  int32_t window_bits_;
+  const int32_t memory_level_;
+  const int32_t window_bits_;
+  const uint32_t chunk_size_;
 };
 
 } // namespace Gzip

test/extensions/filters/http/gzip/gzip_filter_test.cc

@@ -417,6 +417,21 @@ TEST(GzipFilterConfigTest, DEPRECATED_FEATURE_TEST(DeprecatedExtensionFilterName
           deprecated_name));
 }
 
+// Test setting zlib's chunk size.
+TEST_F(GzipFilterTest, ChunkSize) {
+  // Default
+  setUpFilter("{}");
+  EXPECT_EQ(config_->chunkSize(), 4096);
+
+  // Override
+  setUpFilter(R"EOF(
+{
+  "chunk_size": 8192
+}
+)EOF");
+  EXPECT_EQ(config_->chunkSize(), 8192);
+}
+
 } // namespace Gzip
 } // namespace HttpFilters
 } // namespace Extensions