access_logger: add new logger to record metrics derived from substitution formatter values

api/BUILD

@@ -225,6 +225,7 @@ proto_library(
         "//envoy/extensions/filters/http/stateful_session/v3:pkg",
         "//envoy/extensions/filters/http/tap/v3:pkg",
         "//envoy/extensions/filters/http/thrift_to_metadata/v3:pkg",
+        "//envoy/extensions/filters/http/timing_stats/v3:pkg",
         "//envoy/extensions/filters/http/upstream_codec/v3:pkg",
         "//envoy/extensions/filters/http/wasm/v3:pkg",
         "//envoy/extensions/filters/listener/http_inspector/v3:pkg",

api/envoy/extensions/filters/http/timing_stats/v3/BUILD

@@ -0,0 +1,9 @@
+# DO NOT EDIT. This file is generated by tools/proto_format/proto_sync.py.
+
+load("@envoy_api//bazel:api_build_system.bzl", "api_proto_package")
+
+licenses(["notice"])  # Apache 2
+
+api_proto_package(
+    deps = ["@com_github_cncf_xds//udpa/annotations:pkg"],
+)

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

@@ -0,0 +1,75 @@
+syntax = "proto3";
+
+package envoy.extensions.filters.http.timing_stats.v3;
+
+import "envoy/type/matcher/v3/string.proto";
+
+import "google/protobuf/wrappers.proto";
+import "google/protobuf/duration.proto";
+
+import "udpa/annotations/status.proto";
+
+option java_package = "io.envoyproxy.envoy.extensions.filters.http.timing_stats.v3";
+option java_outer_classname = "TimingStatsProto";
+option java_multiple_files = true;
+option go_package = "github.com/envoyproxy/go-control-plane/envoy/extensions/filters/http/timing_stats/v3;timing_statsv3";
+option (udpa.annotations.file_status).package_version_status = ACTIVE;
+
+// [#protodoc-title: Timing_stats]
+// [#extension: envoy.filters.http.timing_stats]
+
+message Config {
+  message TagFormatString {
+    string format_string = 1;
+
+    // Valid values for this tag. If empty, any value is allowed. Must match at least 1 matcher.
+    repeated type.matcher.v3.StringMatcher allowed_values = 2;
+  }
+
+  message TagValue {
+    // onoeof these
+    string fixed_string = 1;
+    TagFormatString format_string = 2;
+  }
+
+  message Stat {
+    string name = 1 [(validate.rules).string = {min_len: 1}];
+    map<string, TagValue> tags = 2;
+    google.protobuf.UInt32Value max_cardinality = 3;
+
+    // How would this be implemented? @kyessenov you've done some work in this area, right?
+    // Or should the expiration be at the filter config level, not the individual stat?
+    google.protobuf.Duration expiration = 4;
+  }
+
+
+  enum TimeUnit {
+    Milliseconds = 0;
+    Microseconds = 1;
+    Nanoseconds = 2;
+  }
+
+  message Histogram {
+    Stat stat = 1;
+    TimeUnit unit = 2;
+    string value = 3; // format string; must evaluate to a number
+  }
+
+  // Increase the counter by the amount of `value`.
+  message Counter {
+    Stat stat = 1;
+    string value = 2; // format string; must evaluate to a numeric value
+  }
+
+  // Increment the counter with described tags each time the tags match.
+  // This only makes sense if at least one of the tags is TagFormatString
+  message Event { // I don't love this name. Any better ideas?
+    Stat stat = 1;
+  }
+
+  string stat_prefix = 1;
+  google.protobuf.UInt32Value max_stats = 2; // Overall maximum number of stats from all types.
+  repeated Histogram histograms = 3;
+  repeated Counter counters = 4;
+  repeated Event events = 5;
+}

api/versioning/BUILD

@@ -164,6 +164,7 @@ proto_library(
         "//envoy/extensions/filters/http/stateful_session/v3:pkg",
         "//envoy/extensions/filters/http/tap/v3:pkg",
         "//envoy/extensions/filters/http/thrift_to_metadata/v3:pkg",
+        "//envoy/extensions/filters/http/timing_stats/v3:pkg",
         "//envoy/extensions/filters/http/upstream_codec/v3:pkg",
         "//envoy/extensions/filters/http/wasm/v3:pkg",
         "//envoy/extensions/filters/listener/http_inspector/v3:pkg",