Fine-granular feature flag for request body compression

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

@@ -49,6 +49,11 @@ message Compressor {
   // Configuration for filter behavior on the request direction.
   message RequestDirectionConfig {
     CommonDirectionConfig common_config = 1;
+
+    // Allow request body compression enabled by request header flag
+    // https://github.com/envoyproxy/envoy/issues/38097
+    // If true, it checks the "X-Request-Compression" header to see whether the request needs to do compression or not
+    bool enable_on_x_header = 2;
   }
 
   // Configuration for filter behavior on the response direction.

api/envoy/extensions/upstreams/http/v3/http_protocol_options.proto

@@ -140,7 +140,6 @@ message HttpProtocolOptions {
     option (validate.required) = true;
 
     // To explicitly configure either HTTP/1 or HTTP/2 (but not both!) use ``explicit_http_config``.
-    // If the ``explicit_http_config`` is empty, HTTP/1.1 is used.
     ExplicitHttpConfig explicit_http_config = 3;
 
     // This allows switching on protocol based on what protocol the downstream

source/extensions/filters/http/compressor/compressor_filter.cc

@@ -113,6 +113,7 @@ CompressorFilterConfig::RequestDirectionConfig::RequestDirectionConfig(
     const std::string& stats_prefix, Stats::Scope& scope, Runtime::Loader& runtime)
     : DirectionConfig(proto_config.request_direction_config().common_config(),
                       stats_prefix + "request.", scope, runtime),
+      enable_on_x_header_(proto_config.request_direction_config().enable_on_x_header()),
       is_set_{proto_config.has_request_direction_config()} {}
 
 CompressorFilterConfig::ResponseDirectionConfig::ResponseDirectionConfig(
@@ -212,8 +213,8 @@ Http::FilterHeadersStatus CompressorFilter::decodeHeaders(Http::RequestHeaderMap
 
   const auto& request_config = config_->requestDirectionConfig();
 
-  if (!end_stream && request_config.compressionEnabled() && !Http::Utility::isUpgrade(headers) &&
-      request_config.isMinimumContentLength(headers) &&
+  if (!end_stream && requestCompressionEnabled(request_config, headers) &&
+      !Http::Utility::isUpgrade(headers) && request_config.isMinimumContentLength(headers) &&
       request_config.isContentTypeAllowed(headers) &&
       !headers.getInline(request_content_encoding_handle.handle()) &&
       isTransferEncodingAllowed(headers)) {
@@ -648,6 +649,26 @@ bool CompressorFilter::compressionEnabled(
              : config.compressionEnabled();
 }
 
+// True if request compression is enabled.
+bool CompressorFilter::requestCompressionEnabled(
+    const CompressorFilterConfig::RequestDirectionConfig& config,
+    const Http::RequestHeaderMap& headers) const {
+  if (config.compressionEnabled()) {
+    return config.compressionEnabled();
+  } else if (config.enableOnXHeader()) {
+    Envoy::Http::HeaderMap::GetResult header_result =
+        headers.get(Envoy::Http::LowerCaseString("X-Request-Compression"));
+    if (header_result.size() > 0) { // Check if the header exists
+      std::string compressionRequired =
+          std::string(header_result.operator[](0)->value().getStringView());
+      if (absl::EqualsIgnoreCase(compressionRequired, "true")) {
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
 bool CompressorFilter::removeAcceptEncodingHeader(
     const CompressorFilterConfig::ResponseDirectionConfig& config,
     const CompressorPerRouteFilterConfig* per_route_config) const {

source/extensions/filters/http/compressor/compressor_filter.h

@@ -107,7 +107,10 @@ class CompressorFilterConfig {
 
     bool compressionEnabled() const override { return is_set_ && compression_enabled_.enabled(); }
 
+    bool enableOnXHeader() const { return enable_on_x_header_; }
+
   private:
+    const bool enable_on_x_header_;
     const bool is_set_;
   };
 
@@ -200,6 +203,8 @@ class CompressorFilter : public Http::PassThroughFilter {
 private:
   bool compressionEnabled(const CompressorFilterConfig::ResponseDirectionConfig& config,
                           const CompressorPerRouteFilterConfig* per_route_config) const;
+  bool requestCompressionEnabled(const CompressorFilterConfig::RequestDirectionConfig& config,
+                                 const Http::RequestHeaderMap& headers) const;
   bool removeAcceptEncodingHeader(const CompressorFilterConfig::ResponseDirectionConfig& config,
                                   const CompressorPerRouteFilterConfig* per_route_config) const;
   bool hasCacheControlNoTransform(Http::ResponseHeaderMap& headers) const;