tracing: make the tracer & tracer manager protocol independent

envoy/tracing/BUILD

@@ -11,18 +11,25 @@ envoy_package()
 envoy_cc_library(
     name = "http_tracer_interface",
     hdrs = ["http_tracer.h"],
+    deps = [
+        ":tracer_interface",
+    ],
+)
+
+envoy_cc_library(
+    name = "tracer_interface",
+    hdrs = ["tracer.h"],
     deps = [
         ":trace_driver_interface",
         "//envoy/access_log:access_log_interface",
-        "//envoy/http:header_map_interface",
     ],
 )
 
 envoy_cc_library(
-    name = "http_tracer_manager_interface",
-    hdrs = ["http_tracer_manager.h"],
+    name = "tracer_manager_interface",
+    hdrs = ["tracer_manager.h"],
     deps = [
-        ":http_tracer_interface",
+        ":tracer_interface",
         "@envoy_api//envoy/config/trace/v3:pkg_cc_proto",
     ],
 )

envoy/tracing/http_tracer.h

@@ -1,31 +1,10 @@
-#pragma once
-
-#include <memory>
-#include <string>
-#include <vector>
-
-#include "envoy/access_log/access_log.h"
-#include "envoy/common/pure.h"
-#include "envoy/http/header_map.h"
-#include "envoy/tracing/trace_driver.h"
-#include "envoy/tracing/trace_reason.h"
+#include "envoy/tracing/tracer.h"
 
 namespace Envoy {
 namespace Tracing {
 
-/**
- * HttpTracer is responsible for handling traces and delegate actions to the
- * corresponding drivers.
- */
-class HttpTracer {
-public:
-  virtual ~HttpTracer() = default;
-
-  virtual SpanPtr startSpan(const Config& config, Http::RequestHeaderMap& request_headers,
-                            const StreamInfo::StreamInfo& stream_info,
-                            const Tracing::Decision tracing_decision) PURE;
-};
-
+// Alias name of Tracer to reduce unnecessary changes in the current code.
+using HttpTracer = Tracer;
 using HttpTracerSharedPtr = std::shared_ptr<HttpTracer>;
 
 } // namespace Tracing

envoy/tracing/tracer.h

@@ -0,0 +1,34 @@
+#pragma once
+
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "envoy/access_log/access_log.h"
+#include "envoy/common/pure.h"
+#include "envoy/tracing/trace_driver.h"
+#include "envoy/tracing/trace_reason.h"
+
+#include "trace_context.h"
+#include "tracer.h"
+
+namespace Envoy {
+namespace Tracing {
+
+/**
+ * Tracer is responsible for handling traces and delegate actions to the
+ * corresponding drivers.
+ */
+class Tracer {
+public:
+  virtual ~Tracer() = default;
+
+  virtual SpanPtr startSpan(const Config& config, TraceContext& trace_context,
+                            const StreamInfo::StreamInfo& stream_info,
+                            const Tracing::Decision tracing_decision) PURE;
+};
+
+using TracerSharedPtr = std::shared_ptr<Tracer>;
+
+} // namespace Tracing
+} // namespace Envoy

envoy/tracing/tracer_manager.h

@@ -0,0 +1,29 @@
+#pragma once
+
+#include "envoy/config/trace/v3/http_tracer.pb.h"
+#include "envoy/tracing/tracer.h"
+
+namespace Envoy {
+namespace Tracing {
+
+/**
+ * An Tracer manager which ensures existence of at most one Tracer instance
+ * for a given configuration.
+ */
+class TracerManager {
+public:
+  virtual ~TracerManager() = default;
+
+  /**
+   * Get an existing Tracer or create a new one for a given configuration.
+   * @param config supplies the configuration for the tracing provider.
+   * @return TracerSharedPtr.
+   */
+  virtual TracerSharedPtr
+  getOrCreateTracer(const envoy::config::trace::v3::Tracing_Http* config) PURE;
+};
+
+using TracerManagerSharedPtr = std::shared_ptr<TracerManager>;
+
+} // namespace Tracing
+} // namespace Envoy

source/common/access_log/access_log_impl.cc

@@ -97,7 +97,7 @@ FilterPtr FilterFactory::fromProto(const envoy::config::accesslog::v3::AccessLog
 bool TraceableRequestFilter::evaluate(const StreamInfo::StreamInfo& info,
                                       const Http::RequestHeaderMap&, const Http::ResponseHeaderMap&,
                                       const Http::ResponseTrailerMap&) const {
-  const Tracing::Decision decision = Tracing::HttpTracerUtility::shouldTraceRequest(info);
+  const Tracing::Decision decision = Tracing::TracerUtility::shouldTraceRequest(info);
   return decision.traced && decision.reason == Tracing::Reason::ServiceForced;
 }
 

source/common/http/conn_manager_impl.cc

@@ -1186,7 +1186,7 @@ void ConnectionManagerImpl::ActiveStream::decodeHeaders(RequestHeaderMapPtr&& he
 
 void ConnectionManagerImpl::ActiveStream::traceRequest() {
   const Tracing::Decision tracing_decision =
-      Tracing::HttpTracerUtility::shouldTraceRequest(filter_manager_.streamInfo());
+      Tracing::TracerUtility::shouldTraceRequest(filter_manager_.streamInfo());
   ConnectionManagerImpl::chargeTracingStats(tracing_decision.reason,
                                             connection_manager_.config_.tracingStats());
 

source/common/tracing/BUILD

@@ -38,34 +38,37 @@ envoy_cc_library(
         "http_tracer_impl.h",
     ],
     deps = [
-        ":common_values_lib",
-        ":null_span_lib",
-        "//envoy/http:request_id_extension_interface",
-        "//envoy/local_info:local_info_interface",
-        "//envoy/runtime:runtime_interface",
-        "//envoy/thread_local:thread_local_interface",
+        ":tracer_lib",
         "//envoy/tracing:http_tracer_interface",
-        "//envoy/upstream:cluster_manager_interface",
-        "//source/common/buffer:zero_copy_input_stream_lib",
-        "//source/common/common:base64_lib",
-        "//source/common/common:macros",
-        "//source/common/common:utility_lib",
         "//source/common/formatter:substitution_formatter_lib",
         "//source/common/grpc:common_lib",
         "//source/common/http:codes_lib",
         "//source/common/http:header_map_lib",
-        "//source/common/http:headers_lib",
-        "//source/common/http:message_lib",
-        "//source/common/http:utility_lib",
         "//source/common/json:json_loader_lib",
-        "//source/common/protobuf:utility_lib",
-        "//source/common/stream_info:utility_lib",
         "@envoy_api//envoy/config/core/v3:pkg_cc_proto",
         "@envoy_api//envoy/type/metadata/v3:pkg_cc_proto",
         "@envoy_api//envoy/type/tracing/v3:pkg_cc_proto",
     ],
 )
 
+envoy_cc_library(
+    name = "tracer_lib",
+    srcs = [
+        "tracer_impl.cc",
+    ],
+    hdrs = [
+        "tracer_impl.h",
+    ],
+    deps = [
+        ":common_values_lib",
+        ":null_span_lib",
+        "//envoy/local_info:local_info_interface",
+        "//envoy/tracing:tracer_interface",
+        "//envoy/upstream:upstream_interface",
+        "//source/common/stream_info:utility_lib",
+    ],
+)
+
 envoy_cc_library(
     name = "tracer_config_lib",
     hdrs = [
@@ -77,17 +80,17 @@ envoy_cc_library(
 )
 
 envoy_cc_library(
-    name = "http_tracer_manager_lib",
+    name = "tracer_manager_lib",
     srcs = [
-        "http_tracer_manager_impl.cc",
+        "tracer_manager_impl.cc",
     ],
     hdrs = [
-        "http_tracer_manager_impl.h",
+        "tracer_manager_impl.h",
     ],
     deps = [
         "//envoy/server:tracer_config_interface",
         "//envoy/singleton:instance_interface",
-        "//envoy/tracing:http_tracer_manager_interface",
+        "//envoy/tracing:tracer_manager_interface",
         "//source/common/common:minimal_logger_lib",
         "//source/common/config:utility_lib",
         "//source/common/tracing:http_tracer_lib",

source/common/tracing/http_tracer_impl.cc

@@ -12,7 +12,6 @@
 #include "source/common/common/fmt.h"
 #include "source/common/common/macros.h"
 #include "source/common/common/utility.h"
-#include "source/common/formatter/substitution_formatter.h"
 #include "source/common/grpc/common.h"
 #include "source/common/http/codes.h"
 #include "source/common/http/header_map_impl.h"
@@ -37,37 +36,6 @@ static absl::string_view valueOrDefault(const Http::HeaderEntry* header,
   return header ? header->value().getStringView() : default_value;
 }
 
-const std::string HttpTracerUtility::IngressOperation = "ingress";
-const std::string HttpTracerUtility::EgressOperation = "egress";
-
-const std::string& HttpTracerUtility::toString(OperationName operation_name) {
-  switch (operation_name) {
-  case OperationName::Ingress:
-    return IngressOperation;
-  case OperationName::Egress:
-    return EgressOperation;
-  }
-
-  return EMPTY_STRING; // Make the compiler happy.
-}
-
-Decision HttpTracerUtility::shouldTraceRequest(const StreamInfo::StreamInfo& stream_info) {
-  // Exclude health check requests immediately.
-  if (stream_info.healthCheck()) {
-    return {Reason::HealthCheck, false};
-  }
-
-  const Tracing::Reason trace_reason = stream_info.traceReason();
-  switch (trace_reason) {
-  case Reason::ClientForced:
-  case Reason::ServiceForced:
-  case Reason::Sampling:
-    return {trace_reason, true};
-  default:
-    return {trace_reason, false};
-  }
-}
-
 static void addTagIfNotNull(Span& span, const std::string& tag, const Http::HeaderEntry* entry) {
   if (entry != nullptr) {
     span.setTag(tag, entry->value().getStringView());
@@ -278,30 +246,5 @@ void HttpTracerUtility::setCommonTags(Span& span, const StreamInfo::StreamInfo&
   }
 }
 
-HttpTracerImpl::HttpTracerImpl(DriverSharedPtr driver, const LocalInfo::LocalInfo& local_info)
-    : driver_(std::move(driver)), local_info_(local_info) {}
-
-SpanPtr HttpTracerImpl::startSpan(const Config& config, Http::RequestHeaderMap& request_headers,
-                                  const StreamInfo::StreamInfo& stream_info,
-                                  const Tracing::Decision tracing_decision) {
-  std::string span_name = HttpTracerUtility::toString(config.operationName());
-
-  if (config.operationName() == OperationName::Egress) {
-    span_name.append(" ");
-    span_name.append(std::string(request_headers.getHostValue()));
-  }
-
-  SpanPtr active_span = driver_->startSpan(config, request_headers, span_name,
-                                           stream_info.startTime(), tracing_decision);
-
-  // Set tags related to the local environment
-  if (active_span) {
-    active_span->setTag(Tracing::Tags::get().NodeId, local_info_.nodeName());
-    active_span->setTag(Tracing::Tags::get().Zone, local_info_.zoneName());
-  }
-
-  return active_span;
-}
-
 } // namespace Tracing
 } // namespace Envoy