Extend OpenTelemetry Tracer with resource detectors

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

@@ -4,7 +4,10 @@ package envoy.config.trace.v3;
 
 import "envoy/config/core/v3/grpc_service.proto";
 
+import "google/protobuf/any.proto";
+
 import "udpa/annotations/status.proto";
+import "validate/validate.proto";
 
 option java_package = "io.envoyproxy.envoy.config.trace.v3";
 option java_outer_classname = "OpentelemetryProto";
@@ -14,6 +17,16 @@ option (udpa.annotations.file_status).package_version_status = ACTIVE;
 
 // [#protodoc-title: OpenTelemetry tracer]
 
+message ResourceDetector {
+  // The name of the resource detector to instantiate.
+  string name = 1 [(validate.rules).string = {min_len: 1}];
+
+  // Resource detector specific configuration which depends on the detector being
+  // instantiated. See the supported detectors for further documentation.
+  // Not required for detectors that don't need a config. E.g., Environment variable Detector
+  google.protobuf.Any typed_config = 2;
+}
+
 // Configuration for the OpenTelemetry tracer.
 //  [#extension: envoy.tracers.opentelemetry]
 message OpenTelemetryConfig {
@@ -25,4 +38,8 @@ message OpenTelemetryConfig {
   // The name for the service. This will be populated in the ResourceSpan Resource attributes.
   // If it is not provided, it will default to "unknown_service:envoy".
   string service_name = 2;
+
+  // An ordered list of resource detectors
+  // [#extension-category: envoy.tracers.opentelemetry.resource_detectors]
+  repeated ResourceDetector resource_detectors = 3;
 }

source/extensions/extensions_build_config.bzl

@@ -254,6 +254,12 @@ EXTENSIONS = {
     "envoy.tracers.skywalking":                         "//source/extensions/tracers/skywalking:config",
     "envoy.tracers.opentelemetry":                      "//source/extensions/tracers/opentelemetry:config",
 
+    #
+    # OpenTelemetry Resource Detectors
+    #
+
+    "envoy.tracers.opentelemetry.resource_detectors.environment":         "//source/extensions/tracers/opentelemetry/resource_detectors/environment:config",
+
     #
     # Transport sockets
     #

source/extensions/extensions_metadata.yaml

@@ -1630,3 +1630,8 @@ envoy.config_mux.sotw_grpc_mux_factory:
   - envoy.config_mux
   security_posture: unknown
   status: stable
+envoy.tracers.opentelemetry.resource_detectors.environment:
+  categories:
+  - envoy.tracers.opentelemetry.resource_detectors
+  security_posture: unknown
+  status: wip

source/extensions/tracers/opentelemetry/BUILD

@@ -41,6 +41,7 @@ envoy_cc_library(
         "//source/common/config:utility_lib",
         "//source/common/tracing:http_tracer_lib",
         "//source/extensions/tracers/common:factory_base_lib",
+        "//source/extensions/tracers/opentelemetry/resource_detectors:resource_detector_lib",
         "@envoy_api//envoy/config/trace/v3:pkg_cc_proto",
         "@opentelemetry_proto//:trace_cc_proto",
     ],

source/extensions/tracers/opentelemetry/config.cc

@@ -6,6 +6,7 @@
 
 #include "source/common/common/logger.h"
 #include "source/extensions/tracers/opentelemetry/opentelemetry_tracer_impl.h"
+#include "source/extensions/tracers/opentelemetry/resource_detectors/resource_provider.h"
 
 namespace Envoy {
 namespace Extensions {
@@ -18,7 +19,9 @@ OpenTelemetryTracerFactory::OpenTelemetryTracerFactory()
 Tracing::DriverSharedPtr OpenTelemetryTracerFactory::createTracerDriverTyped(
     const envoy::config::trace::v3::OpenTelemetryConfig& proto_config,
     Server::Configuration::TracerFactoryContext& context) {
-  return std::make_shared<Driver>(proto_config, context);
+
+  ResourceProviderImpl resource_provider;
+  return std::make_shared<Driver>(proto_config, context, resource_provider);
 }
 
 /**

source/extensions/tracers/opentelemetry/opentelemetry_tracer_impl.cc

@@ -8,6 +8,8 @@
 #include "source/common/common/logger.h"
 #include "source/common/config/utility.h"
 #include "source/common/tracing/http_tracer_impl.h"
+#include "source/extensions/tracers/opentelemetry/resource_detectors/resource_detector.h"
+#include "source/extensions/tracers/opentelemetry/resource_detectors/resource_provider.h"
 
 #include "opentelemetry/proto/collector/trace/v1/trace_service.pb.h"
 #include "opentelemetry/proto/trace/v1/trace.pb.h"
@@ -21,13 +23,17 @@ namespace Tracers {
 namespace OpenTelemetry {
 
 Driver::Driver(const envoy::config::trace::v3::OpenTelemetryConfig& opentelemetry_config,
-               Server::Configuration::TracerFactoryContext& context)
+               Server::Configuration::TracerFactoryContext& context,
+               const ResourceProvider& resource_provider)
     : tls_slot_ptr_(context.serverFactoryContext().threadLocal().allocateSlot()),
       tracing_stats_{OPENTELEMETRY_TRACER_STATS(
           POOL_COUNTER_PREFIX(context.serverFactoryContext().scope(), "tracing.opentelemetry"))} {
   auto& factory_context = context.serverFactoryContext();
+  Resource resource = resource_provider.getResource(opentelemetry_config, context);
+
   // Create the tracer in Thread Local Storage.
-  tls_slot_ptr_->set([opentelemetry_config, &factory_context, this](Event::Dispatcher& dispatcher) {
+  tls_slot_ptr_->set([opentelemetry_config, &factory_context, this,
+                      resource](Event::Dispatcher& dispatcher) {
     OpenTelemetryGrpcTraceExporterPtr exporter;
     if (opentelemetry_config.has_grpc_service()) {
       Grpc::AsyncClientFactoryPtr&& factory =
@@ -39,7 +45,7 @@ Driver::Driver(const envoy::config::trace::v3::OpenTelemetryConfig& opentelemetr
     }
     TracerPtr tracer = std::make_unique<Tracer>(
         std::move(exporter), factory_context.timeSource(), factory_context.api().randomGenerator(),
-        factory_context.runtime(), dispatcher, tracing_stats_, opentelemetry_config.service_name());
+        factory_context.runtime(), dispatcher, tracing_stats_, resource);
 
     return std::make_shared<TlsTracer>(std::move(tracer));
   });

source/extensions/tracers/opentelemetry/opentelemetry_tracer_impl.h

@@ -9,6 +9,7 @@
 #include "source/common/singleton/const_singleton.h"
 #include "source/extensions/tracers/common/factory_base.h"
 #include "source/extensions/tracers/opentelemetry/grpc_trace_exporter.h"
+#include "source/extensions/tracers/opentelemetry/resource_detectors/resource_provider.h"
 #include "source/extensions/tracers/opentelemetry/tracer.h"
 
 namespace Envoy {
@@ -30,7 +31,8 @@ using OpenTelemetryConstants = ConstSingleton<OpenTelemetryConstantValues>;
 class Driver : Logger::Loggable<Logger::Id::tracing>, public Tracing::Driver {
 public:
   Driver(const envoy::config::trace::v3::OpenTelemetryConfig& opentelemetry_config,
-         Server::Configuration::TracerFactoryContext& context);
+         Server::Configuration::TracerFactoryContext& context,
+         const ResourceProvider& resource_provider);
 
   // Tracing::Driver
   Tracing::SpanPtr startSpan(const Tracing::Config& config, Tracing::TraceContext& trace_context,

source/extensions/tracers/opentelemetry/resource_detectors/BUILD

@@ -0,0 +1,27 @@
+load(
+    "//bazel:envoy_build_system.bzl",
+    "envoy_cc_library",
+    "envoy_extension_package",
+)
+
+licenses(["notice"])  # Apache 2
+
+envoy_extension_package()
+
+envoy_cc_library(
+    name = "resource_detector_lib",
+    srcs = [
+        "resource_provider.cc",
+    ],
+    hdrs = [
+        "resource_detector.h",
+        "resource_provider.h",
+    ],
+    deps = [
+        "//envoy/config:typed_config_interface",
+        "//envoy/server:tracer_config_interface",
+        "//source/common/common:logger_lib",
+        "//source/common/config:utility_lib",
+        "@envoy_api//envoy/config/trace/v3:pkg_cc_proto",
+    ],
+)

source/extensions/tracers/opentelemetry/resource_detectors/environment/BUILD

@@ -0,0 +1,31 @@
+load(
+    "//bazel:envoy_build_system.bzl",
+    "envoy_cc_extension",
+    "envoy_cc_library",
+    "envoy_extension_package",
+)
+
+licenses(["notice"])  # Apache 2
+
+envoy_extension_package()
+
+envoy_cc_extension(
+    name = "config",
+    srcs = ["config.cc"],
+    hdrs = ["config.h"],
+    deps = [
+        ":resource_detector_environment_lib",
+        "//envoy/registry",
+        "//source/common/config:utility_lib",
+    ],
+)
+
+envoy_cc_library(
+    name = "resource_detector_environment_lib",
+    srcs = ["environment_resource_detector.cc"],
+    hdrs = ["environment_resource_detector.h"],
+    deps = [
+        "//source/common/config:datasource_lib",
+        "//source/extensions/tracers/opentelemetry/resource_detectors:resource_detector_lib",
+    ],
+)

source/extensions/tracers/opentelemetry/resource_detectors/environment/config.cc

@@ -0,0 +1,25 @@
+#include "config.h"
+
+#include "source/common/config/utility.h"
+
+#include "environment_resource_detector.h"
+
+namespace Envoy {
+namespace Extensions {
+namespace Tracers {
+namespace OpenTelemetry {
+
+ResourceDetectorPtr EnvironmentResourceDetectorFactory::createResourceDetector(
+    Server::Configuration::TracerFactoryContext& context) {
+  return std::make_shared<EnvironmentResourceDetector>(context);
+}
+
+/**
+ * Static registration for the Env resource detector factory. @see RegisterFactory.
+ */
+REGISTER_FACTORY(EnvironmentResourceDetectorFactory, ResourceDetectorFactory);
+
+} // namespace OpenTelemetry
+} // namespace Tracers
+} // namespace Extensions
+} // namespace Envoy

source/extensions/tracers/opentelemetry/resource_detectors/environment/config.h

@@ -0,0 +1,37 @@
+#pragma once
+
+#include <string>
+
+#include "source/extensions/tracers/opentelemetry/resource_detectors/resource_detector.h"
+
+namespace Envoy {
+namespace Extensions {
+namespace Tracers {
+namespace OpenTelemetry {
+
+/**
+ * Config registration for the Environment resource detector. @see ResourceDetectorFactory.
+ */
+class EnvironmentResourceDetectorFactory : public ResourceDetectorFactory {
+public:
+  /**
+   * @brief Create a Resource Detector that reads from the OTEL_RESOURCE_ATTRIBUTES
+   * environment variable.
+   *
+   * @param context
+   * @return ResourceDetectorPtr
+   */
+  ResourceDetectorPtr
+  createResourceDetector(Server::Configuration::TracerFactoryContext& context) override;
+
+  std::string name() const override {
+    return "envoy.tracers.opentelemetry.resource_detectors.environment";
+  }
+};
+
+DECLARE_FACTORY(EnvironmentResourceDetectorFactory);
+
+} // namespace OpenTelemetry
+} // namespace Tracers
+} // namespace Extensions
+} // namespace Envoy

source/extensions/tracers/opentelemetry/resource_detectors/environment/environment_resource_detector.cc

@@ -0,0 +1,56 @@
+#include "environment_resource_detector.h"
+
+#include <sstream>
+#include <string>
+
+#include "source/common/config/datasource.h"
+#include "source/extensions/tracers/opentelemetry/resource_detectors/resource_detector.h"
+
+namespace Envoy {
+namespace Extensions {
+namespace Tracers {
+namespace OpenTelemetry {
+
+constexpr absl::string_view kOtelResourceAttributesEnv = "OTEL_RESOURCE_ATTRIBUTES";
+
+/**
+ * @brief Detects a resource from the OTEL_RESOURCE_ATTRIBUTES environment variable
+ * Based on the OTel C++ SDK:
+ * https://github.com/open-telemetry/opentelemetry-cpp/blob/v1.11.0/sdk/src/resource/resource_detector.cc
+ *
+ * @return Resource A resource with the attributes from the OTEL_RESOURCE_ATTRIBUTES environment
+ * variable.
+ */
+Resource EnvironmentResourceDetector::detect() {
+  envoy::config::core::v3::DataSource ds;
+  ds.set_environment_variable(kOtelResourceAttributesEnv);
+
+  Resource resource;
+  resource.schemaUrl = "";
+
+  TRY_NEEDS_AUDIT {
+    auto attributes_str = Config::DataSource::read(ds, true, context_.serverFactoryContext().api());
+    if (attributes_str.empty()) {
+      return resource;
+    }
+
+    std::istringstream iss(attributes_str);
+    std::string token;
+    while (std::getline(iss, token, ',')) {
+      size_t pos = token.find('=');
+      std::string key = token.substr(0, pos);
+      std::string value = token.substr(pos + 1);
+      resource.attributes[key] = value;
+    }
+  }
+  END_TRY catch (const EnvoyException& e) {
+    ENVOY_LOG(error, "Failed to read resource attributes: {}.", e.what());
+  }
+
+  return resource;
+}
+
+} // namespace OpenTelemetry
+} // namespace Tracers
+} // namespace Extensions
+} // namespace Envoy

source/extensions/tracers/opentelemetry/resource_detectors/environment/environment_resource_detector.h

@@ -0,0 +1,34 @@
+#pragma once
+
+#include "envoy/server/factory_context.h"
+
+#include "source/common/common/logger.h"
+#include "source/extensions/tracers/opentelemetry/resource_detectors/resource_detector.h"
+
+namespace Envoy {
+namespace Extensions {
+namespace Tracers {
+namespace OpenTelemetry {
+
+/**
+ * @brief A resource detector that extracts attributes from the OTEL_RESOURCE_ATTRIBUTES environment
+ * variable.
+ * @see
+ * https://github.com/open-telemetry/opentelemetry-specification/blob/v1.24.0/specification/resource/sdk.md#detecting-resource-information-from-the-environment
+ *
+ */
+class EnvironmentResourceDetector : public ResourceDetector, Logger::Loggable<Logger::Id::tracing> {
+public:
+  EnvironmentResourceDetector(Server::Configuration::TracerFactoryContext& context)
+      : context_(context) {}
+  Resource detect() override;
+
+private:
+  Server::Configuration::TracerFactoryContext&
+      context_; // TODO, is keeping a reference ok (ownership)?
+};
+
+} // namespace OpenTelemetry
+} // namespace Tracers
+} // namespace Extensions
+} // namespace Envoy