tracing: general tracing support

api/envoy/config/trace/v3/trace.proto

@@ -8,6 +8,7 @@ import public "envoy/config/trace/v3/http_tracer.proto";
 import public "envoy/config/trace/v3/lightstep.proto";
 import public "envoy/config/trace/v3/opencensus.proto";
 import public "envoy/config/trace/v3/service.proto";
+import public "envoy/config/trace/v3/tracer.proto";
 import public "envoy/config/trace/v3/zipkin.proto";
 
 option java_package = "io.envoyproxy.envoy.config.trace.v3";

api/envoy/config/trace/v3/tracer.proto

@@ -0,0 +1,29 @@
+syntax = "proto3";
+
+package envoy.config.trace.v3;
+
+import "google/protobuf/any.proto";
+
+import "udpa/annotations/status.proto";
+import "udpa/annotations/versioning.proto";
+import "validate/validate.proto";
+
+option java_package = "io.envoyproxy.envoy.config.trace.v3";
+option java_outer_classname = "TracerProto";
+option java_multiple_files = true;
+option (udpa.annotations.file_status).package_version_status = ACTIVE;
+
+// [#protodoc-title: Tracing]
+// Tracing :ref:`architecture overview <arch_overview_tracing>`.
+
+// The tracing configuration specifies settings for an tracer provider used by Envoy.
+message TracerProvider {
+  // The name of the trace driver to instantiate. The name must match a supported trace driver.
+  // See the :ref:`extensions listed in typed_config below <extension_category_envoy.tracers>` for the
+  // default list of the trace driver.
+  string name = 1 [(validate.rules).string = {min_len: 1}];
+
+  // Trace driver specific configuration which must be set according to the driver being instantiated.
+  // [#extension-category: envoy.tracers]
+  google.protobuf.Any typed_config = 2;
+}

include/envoy/http/BUILD

@@ -105,6 +105,7 @@ envoy_cc_library(
     ],
     deps = [
         ":header_formatter_interface",
+        "//include/envoy/tracing:trace_context_interface",
         "//source/common/common:assert_lib",
         "//source/common/common:hash_lib",
     ],

include/envoy/http/header_map.h

@@ -11,6 +11,7 @@
 #include "envoy/common/optref.h"
 #include "envoy/common/pure.h"
 #include "envoy/http/header_formatter.h"
+#include "envoy/tracing/trace_context.h"
 
 #include "common/common/assert.h"
 #include "common/common/hash.h"
@@ -64,7 +65,7 @@ class LowerCaseString {
     return *this;
   }
 
-  explicit LowerCaseString(const std::string& new_string) : string_(new_string) {
+  explicit LowerCaseString(const absl::string_view new_string) : string_(new_string) {
     ASSERT(valid());
     lower();
   }
@@ -817,7 +818,8 @@ class RequestOrResponseHeaderMap : public HeaderMap {
 // Request headers.
 class RequestHeaderMap
     : public RequestOrResponseHeaderMap,
-      public CustomInlineHeaderBase<CustomInlineHeaderRegistry::Type::RequestHeaders> {
+      public CustomInlineHeaderBase<CustomInlineHeaderRegistry::Type::RequestHeaders>,
+      public Tracing::TracingContext {
 public:
   INLINE_REQ_STRING_HEADERS(DEFINE_INLINE_STRING_HEADER)
   INLINE_REQ_NUMERIC_HEADERS(DEFINE_INLINE_NUMERIC_HEADER)

include/envoy/server/tracer_config.h

@@ -41,22 +41,22 @@ class TracerFactory : public Config::TypedFactory {
   ~TracerFactory() override = default;
 
   /**
-   * Create a particular HttpTracer implementation. If the implementation is unable to produce an
-   * HttpTracer with the provided parameters, it should throw an EnvoyException in the case of
-   * general error or a Json::Exception if the json configuration is erroneous. The returned
+   * Create a particular tracer driver implementation. If the implementation is unable to produce
+   * an tracer driver with the provided parameters, it should throw an EnvoyException in the case
+   * of general error or a Json::Exception if the json configuration is erroneous. The returned
    * pointer should always be valid.
    *
    * NOTE: Due to the corner case of OpenCensus, who can only support a single tracing
-   *       configuration per entire process, the returned HttpTracer instance is not guaranteed
+   *       configuration per entire process, the returned Driver instance is not guaranteed
    *       to be unique.
    *       That is why the return type has been changed to std::shared_ptr<> instead of a more
    *       idiomatic std::unique_ptr<>.
    *
    * @param config supplies the proto configuration for the HttpTracer
    * @param context supplies the factory context
    */
-  virtual Tracing::HttpTracerSharedPtr createHttpTracer(const Protobuf::Message& config,
-                                                        TracerFactoryContext& context) PURE;
+  virtual Tracing::DriverSharedPtr createTracerDriver(const Protobuf::Message& config,
+                                                      TracerFactoryContext& context) PURE;
 
   std::string category() const override { return "envoy.tracers"; }
 };

include/envoy/tracing/BUILD

@@ -8,12 +8,26 @@ licenses(["notice"])  # Apache 2
 
 envoy_package()
 
+envoy_cc_library(
+    name = "trace_context_interface",
+    hdrs = ["trace_context.h"],
+)
+
+envoy_cc_library(
+    name = "trace_driver_interface",
+    hdrs = ["trace_driver.h"],
+    deps = [
+        ":trace_context_interface",
+        ":trace_reason_interface",
+        "//include/envoy/stream_info:stream_info_interface",
+    ],
+)
+
 envoy_cc_library(
     name = "http_tracer_interface",
     hdrs = ["http_tracer.h"],
     deps = [
-        ":trace_reason_interface",
-        "//include/envoy/access_log:access_log_interface",
+        ":trace_driver_interface",
         "//include/envoy/http:header_map_interface",
     ],
 )