1 files changed, 107 insertions, 0 deletions
diff --git a/src/common/tracer.h b/src/common/tracer.h
new file mode 100644
index 000000000..9d13c78aa
--- /dev/null
+++ b/src/common/tracer.h
@@ -0,0 +1,107 @@
+// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
+// vim: ts=8 sw=2 smarttab
+
+#pragma once
+
+#include "acconfig.h"
+#include "include/buffer.h"
+
+#ifdef HAVE_JAEGER
+#include "opentelemetry/trace/provider.h"
+
+using jspan = opentelemetry::nostd::shared_ptr<opentelemetry::trace::Span>;
+using jspan_context = opentelemetry::trace::SpanContext;
+using jspan_attribute = opentelemetry::common::AttributeValue;
+
+namespace tracing {
+
+class Tracer {
+ private:
+  const static opentelemetry::nostd::shared_ptr<opentelemetry::trace::Tracer> noop_tracer;
+  const static jspan noop_span;
+  opentelemetry::nostd::shared_ptr<opentelemetry::trace::Tracer> tracer;
+
+ public:
+  Tracer() = default;
+  Tracer(opentelemetry::nostd::string_view service_name);
+
+  void init(opentelemetry::nostd::string_view service_name);
+
+  bool is_enabled() const;
+  // creates and returns a new span with `trace_name`
+  // this span represents a trace, since it has no parent.
+  jspan start_trace(opentelemetry::nostd::string_view trace_name);
+
+  // creates and returns a new span with `trace_name`
+  // if false is given to `trace_is_enabled` param, noop span will be returned
+  jspan start_trace(opentelemetry::nostd::string_view trace_name, bool trace_is_enabled);
+
+  // creates and returns a new span with `span_name` which parent span is `parent_span'
+  jspan add_span(opentelemetry::nostd::string_view span_name, const jspan& parent_span);
+  // creates and return a new span with `span_name`
+  // the span is added to the trace which it's context is `parent_ctx`.
+  // parent_ctx contains the required information of the trace.
+  jspan add_span(opentelemetry::nostd::string_view span_name, const jspan_context& parent_ctx);
+
+};
+
+void encode(const jspan_context& span, ceph::buffer::list& bl, uint64_t f = 0);
+void decode(jspan_context& span_ctx, ceph::buffer::list::const_iterator& bl);
+
+} // namespace tracing
+
+
+#else  // !HAVE_JAEGER
+
+#include <string_view>
+
+class Value {
+ public:
+  template <typename T> Value(T val) {}
+};
+
+using jspan_attribute = Value;
+
+struct jspan_context {
+  jspan_context() {}
+  jspan_context(bool sampled_flag, bool is_remote) {}
+};
+
+struct span_stub {
+  jspan_context _ctx;
+  template <typename T>
+  void SetAttribute(std::string_view key, const T& value) const noexcept {}
+  void AddEvent(std::string_view) {}
+  void AddEvent(std::string_view, std::initializer_list<std::pair<std::string_view, jspan_attribute>> fields) {}
+  template <typename T> void AddEvent(std::string_view name, const T& fields = {}) {}
+  const jspan_context& GetContext() { return _ctx; }
+  void UpdateName(std::string_view) {}
+  bool IsRecording() { return false; }
+};
+
+class jspan {
+  span_stub span;
+ public:
+  span_stub& operator*() { return span; }
+  const span_stub& operator*() const { return span; }
+
+  span_stub* operator->() { return &span; }
+  const span_stub* operator->() const { return &span; }
+
+  operator bool() const { return false; }
+};
+
+namespace tracing {
+
+struct Tracer {
+  bool is_enabled() const { return false; }
+  jspan start_trace(std::string_view, bool enabled = true) { return {}; }
+  jspan add_span(std::string_view, const jspan&) { return {}; }
+  jspan add_span(std::string_view span_name, const jspan_context& parent_ctx) { return {}; }
+  void init(std::string_view service_name) {}
+};
+  inline void encode(const jspan_context& span, bufferlist& bl, uint64_t f=0) {}
+  inline void decode(jspan_context& span_ctx, ceph::buffer::list::const_iterator& bl) {}
+}
+
+#endif // !HAVE_JAEGER