Replace rapidjson with nlohmann/json

bazel/external/json.BUILD

@@ -0,0 +1,21 @@
+load("@rules_cc//cc:defs.bzl", "cc_library")
+
+licenses(["notice"])  # Apache 2
+
+cc_library(
+    name = "nlohmann_json_lib",
+    hdrs = glob([
+        "include/nlohmann/*.hpp",
+        "include/nlohmann/**/*.hpp",
+        "include/nlohmann/*/*/*.hpp",
+    ]),
+    includes = ["external/nlohmann_json_lib"],
+    visibility = ["//visibility:public"],
+)
+
+cc_library(
+    name = "json",
+    includes = ["include"],
+    visibility = ["//visibility:public"],
+    deps = [":nlohmann_json_lib"],
+)

bazel/repositories.bzl

@@ -144,6 +144,7 @@ def envoy_dependencies(skip_targets = []):
     _com_github_nghttp2_nghttp2()
     _com_github_nodejs_http_parser()
     _com_github_tencent_rapidjson()
+    _com_github_nlohmann_json()
     _com_google_absl()
     _com_google_googletest()
     _com_google_protobuf()
@@ -428,6 +429,16 @@ def _com_github_tencent_rapidjson():
         actual = "@com_github_tencent_rapidjson//:rapidjson",
     )
 
+def _com_github_nlohmann_json():
+    external_http_archive(
+        name = "com_github_nlohmann_json",
+        build_file = "@envoy//bazel/external:json.BUILD",
+    )
+    native.bind(
+        name = "json",
+        actual = "@com_github_nlohmann_json//:json",
+    )
+
 def _com_github_nodejs_http_parser():
     external_http_archive(
         name = "com_github_nodejs_http_parser",

bazel/repository_locations.bzl

@@ -443,6 +443,20 @@ REPOSITORY_LOCATIONS_SPEC = dict(
         release_date = "2019-12-03",
         cpe = "cpe:2.3:a:tencent:rapidjson:*",
     ),
+    com_github_nlohmann_json = dict(
+        project_name = "nlohmann JSON",
+        project_desc = "Fast JSON parser/generator for C++",
+        project_url = "https://nlohmann.github.io/json",
+        version = "3.9.1",
+        sha256 = "4cf0df69731494668bdd6460ed8cb269b68de9c19ad8c27abc24cd72605b2d5b",
+        strip_prefix = "json-{version}",
+        urls = ["https://github.com/nlohmann/json/archive/v{version}.tar.gz"],
+        # This will be a replacement for rapidJSON used in extensions and may also be a fast
+        # replacement for protobuf JSON.
+        use_category = ["controlplane", "dataplane_core"],
+        release_date = "2020-08-06",
+        cpe = "cpe:2.3:a:json_project:json:*",
+    ),
     com_github_twitter_common_lang = dict(
         project_name = "twitter.common.lang (Thrift)",
         project_desc = "twitter.common Python language and compatibility facilities",

docs/root/version_history/current.rst

@@ -52,13 +52,15 @@ Removed Config or Runtime
 
 New Features
 ------------
+
 * access log: added the :ref:`formatters <envoy_v3_api_field_config.core.v3.SubstitutionFormatString.formatters>` extension point for custom formatters (command operators).
 * access log: support command operator: %REQUEST_HEADERS_BYTES%, %RESPONSE_HEADERS_BYTES% and %RESPONSE_TRAILERS_BYTES%.
 * dispatcher: supports a stack of `Envoy::ScopeTrackedObject` instead of a single tracked object. This will allow Envoy to dump more debug information on crash.
 * grpc_json_transcoder: added option :ref:`strict_http_request_validation <envoy_v3_api_field_extensions.filters.http.grpc_json_transcoder.v3.GrpcJsonTranscoder.strict_http_request_validation>` to reject invalid requests early.
 * grpc_json_transcoder: filter can now be configured on per-route/per-vhost level as well. Leaving empty list of services in the filter configuration disables transcoding on the specific route.
 * http: added support for :ref:`:ref:`preconnecting <envoy_v3_api_msg_config.cluster.v3.Cluster.PreconnectPolicy>`. Preconnecting is off by default, but recommended for clusters serving latency-sensitive traffic, especially if using HTTP/1.1.
 * http: change frame flood and abuse checks to the upstream HTTP/2 codec to ON by default. It can be disabled by setting the `envoy.reloadable_features.upstream_http2_flood_checks` runtime key to false.
+* json: introduced new JSON parser (https://github.com/nlohmann/json) to replace RapidJSON. The new parser is disabled by default. To test the new RapidJSON parser, enable the runtime feature `envoy.reloadable_features.remove_legacy_json`.
 * overload: add support for scaling :ref:`transport connection timeouts<envoy_v3_api_enum_value_config.overload.v3.ScaleTimersOverloadActionConfig.TimerType.TRANSPORT_SOCKET_CONNECT>`. This can be used to reduce the TLS handshake timeout in response to overload.
 * server: added :ref:`fips_mode <statistics>` statistic.
 * tcp_proxy: add support for converting raw TCP streams into HTTP/1.1 CONNECT requests. See :ref:`upgrade documentation <tunneling-tcp-over-http>` for details.

include/envoy/json/json_object.h

@@ -79,12 +79,6 @@ class Object {
    */
   virtual ObjectSharedPtr getObject(const std::string& name, bool allow_empty = false) const PURE;
 
-  /**
-   * Determine if an object is null.
-   * @return bool is the object null?
-   */
-  virtual bool isNull() const PURE;
-
   /**
    * Determine if an object has type Object.
    * @return bool is the object an Object?
@@ -181,21 +175,6 @@ class Object {
    */
   virtual std::string asString() const PURE;
 
-  /**
-   * @return the value of the object as a boolean (where the object is a boolean).
-   */
-  virtual bool asBoolean() const PURE;
-
-  /**
-   * @return the value of the object as a double (where the object is a double).
-   */
-  virtual double asDouble() const PURE;
-
-  /**
-   * @return the value of the object as an integer (where the object is an integer).
-   */
-  virtual int64_t asInteger() const PURE;
-
   /**
    * @return the JSON string representation of the object.
    */

source/common/json/BUILD

@@ -9,9 +9,9 @@ licenses(["notice"])  # Apache 2
 envoy_package()
 
 envoy_cc_library(
-    name = "json_loader_lib",
-    srcs = ["json_loader.cc"],
-    hdrs = ["json_loader.h"],
+    name = "json_internal_legacy_lib",
+    srcs = ["json_internal_legacy.cc"],
+    hdrs = ["json_internal_legacy.h"],
     external_deps = [
         "rapidjson",
     ],
@@ -23,3 +23,31 @@ envoy_cc_library(
         "//source/common/protobuf:utility_lib",
     ],
 )
+
+envoy_cc_library(
+    name = "json_internal_lib",
+    srcs = ["json_internal.cc"],
+    hdrs = ["json_internal.h"],
+    external_deps = [
+        "json",
+    ],
+    deps = [
+        "//include/envoy/json:json_object_interface",
+        "//source/common/common:assert_lib",
+        "//source/common/common:hash_lib",
+        "//source/common/common:utility_lib",
+        "//source/common/protobuf:utility_lib",
+    ],
+)
+
+envoy_cc_library(
+    name = "json_loader_lib",
+    srcs = ["json_loader.cc"],
+    hdrs = ["json_loader.h"],
+    deps = [
+        ":json_internal_legacy_lib",
+        ":json_internal_lib",
+        "//include/envoy/json:json_object_interface",
+        "//source/common/runtime:runtime_features_lib",
+    ],
+)