Line data    Source code

       1             : #pragma once
       2             : 
       3             : #include <map>
       4             : #include <memory>
       5             : #include <string>
       6             : #include <vector>
       7             : 
       8             : #include "envoy/common/optref.h"
       9             : #include "envoy/config/typed_config.h"
      10             : #include "envoy/server/tracer_config.h"
      11             : #include "envoy/tracing/trace_context.h"
      12             : 
      13             : #include "absl/types/optional.h"
      14             : #include "opentelemetry/proto/trace/v1/trace.pb.h"
      15             : 
      16             : namespace Envoy {
      17             : namespace Extensions {
      18             : namespace Tracers {
      19             : namespace OpenTelemetry {
      20             : 
      21             : class SpanContext;
      22             : 
      23             : enum class Decision {
      24             :   // IsRecording will be false, the Span will not be recorded and all events and attributes will be
      25             :   // dropped.
      26             :   DROP,
      27             :   // IsRecording will be true, but the Sampled flag MUST NOT be set.
      28             :   RECORD_ONLY,
      29             :   // IsRecording will be true and the Sampled flag MUST be set.
      30             :   RECORD_AND_SAMPLE
      31             : };
      32             : 
      33             : /**
      34             :  * @brief The type of the span.
      35             :  * see
      36             :  * https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/trace/api.md#spankind
      37             :  */
      38             : using OTelSpanKind = ::opentelemetry::proto::trace::v1::Span::SpanKind;
      39             : 
      40             : struct SamplingResult {
      41             :   /// @see Decision
      42             :   Decision decision;
      43             :   // A set of span Attributes that will also be added to the Span. Can be nullptr.
      44             :   std::unique_ptr<const std::map<std::string, std::string>> attributes;
      45             :   // A Tracestate that will be associated with the Span. If the sampler
      46             :   // returns an empty Tracestate here, the Tracestate will be cleared, so samplers SHOULD normally
      47             :   // return the passed-in Tracestate if they do not intend to change it
      48             :   std::string tracestate;
      49             : 
      50           0 :   inline bool isRecording() const {
      51           0 :     return decision == Decision::RECORD_ONLY || decision == Decision::RECORD_AND_SAMPLE;
      52           0 :   }
      53             : 
      54           0 :   inline bool isSampled() const { return decision == Decision::RECORD_AND_SAMPLE; }
      55             : };
      56             : 
      57             : /**
      58             :  * @brief The base type for all samplers
      59             :  * see https://opentelemetry.io/docs/specs/otel/trace/sdk/#sampler
      60             :  *
      61             :  */
      62             : class Sampler {
      63             : public:
      64           0 :   virtual ~Sampler() = default;
      65             : 
      66             :   /**
      67             :    * @brief Decides if a trace should be sampled.
      68             :    *
      69             :    * @param parent_context Span context describing the parent span. The Span's SpanContext may be
      70             :    * invalid to indicate a root span.
      71             :    * @param trace_id Trace id of the Span to be created. If the parent SpanContext contains a valid
      72             :    * TraceId, they MUST always match.
      73             :    * @param name Name of the Span to be created.
      74             :    * @param spankind Span kind of the Span to be created.
      75             :    * @param trace_context TraceContext containing potential initial span attributes
      76             :    * @param links Collection of links that will be associated with the Span to be created.
      77             :    * @return SamplingResult @see SamplingResult
      78             :    */
      79             :   virtual SamplingResult shouldSample(const absl::optional<SpanContext> parent_context,
      80             :                                       const std::string& trace_id, const std::string& name,
      81             :                                       OTelSpanKind spankind,
      82             :                                       OptRef<const Tracing::TraceContext> trace_context,
      83             :                                       const std::vector<SpanContext>& links) PURE;
      84             : 
      85             :   /**
      86             :    * @brief Returns a sampler description or name.
      87             :    *
      88             :    * @return The sampler name or short description with the configuration.
      89             :    */
      90             :   virtual std::string getDescription() const PURE;
      91             : };
      92             : 
      93             : using SamplerSharedPtr = std::shared_ptr<Sampler>;
      94             : 
      95             : /*
      96             :  * A factory for creating a sampler
      97             :  */
      98             : class SamplerFactory : public Envoy::Config::TypedFactory {
      99             : public:
     100           0 :   ~SamplerFactory() override = default;
     101             : 
     102             :   /**
     103             :    * @brief Creates a sampler
     104             :    * @param config The sampler protobuf config.
     105             :    * @param context The TracerFactoryContext.
     106             :    * @return SamplerSharedPtr A sampler.
     107             :    */
     108             :   virtual SamplerSharedPtr createSampler(const Protobuf::Message& config,
     109             :                                          Server::Configuration::TracerFactoryContext& context) PURE;
     110             : 
     111           4 :   std::string category() const override { return "envoy.tracers.opentelemetry.samplers"; }
     112             : };
     113             : 
     114             : using SamplerFactoryPtr = std::unique_ptr<SamplerFactory>;
     115             : 
     116             : } // namespace OpenTelemetry
     117             : } // namespace Tracers
     118             : } // namespace Extensions
     119             : } // namespace Envoy