From 3503d72e7f5d404281a192ee801b7d17fdf69111 Mon Sep 17 00:00:00 2001
From: Ryan Burn <ryan.burn@gmail.com>
Date: Mon, 2 Mar 2020 23:25:43 -0800
Subject: [PATCH 01/17] Start Recorder api

---
 sdk/src/{opentelemetry => }/context/TBD       |  0
 .../distributedcontext/TBD                    |  0
 sdk/src/{opentelemetry => }/internal/TBD      |  0
 sdk/src/{opentelemetry => }/logs/TBD          |  0
 sdk/src/{opentelemetry => }/metrics/TBD       |  0
 sdk/src/opentelemetry/trace/tracer_handle.h   | 27 -----------------
 sdk/src/{opentelemetry => }/resource/TBD      |  0
 sdk/src/trace/BUILD                           | 24 +++++++++++++++
 sdk/src/trace/recordable.h                    | 29 +++++++++++++++++++
 sdk/src/trace/recorder.h                      | 22 ++++++++++++++
 sdk/src/trace/span.cc                         | 19 ++++++++++++
 sdk/src/trace/span.h                          | 25 ++++++++++++++++
 sdk/src/trace/tracer.cc                       | 19 ++++++++++++
 sdk/src/trace/tracer.h                        | 28 ++++++++++++++++++
 14 files changed, 166 insertions(+), 27 deletions(-)
 rename sdk/src/{opentelemetry => }/context/TBD (100%)
 rename sdk/src/{opentelemetry => }/distributedcontext/TBD (100%)
 rename sdk/src/{opentelemetry => }/internal/TBD (100%)
 rename sdk/src/{opentelemetry => }/logs/TBD (100%)
 rename sdk/src/{opentelemetry => }/metrics/TBD (100%)
 delete mode 100644 sdk/src/opentelemetry/trace/tracer_handle.h
 rename sdk/src/{opentelemetry => }/resource/TBD (100%)
 create mode 100644 sdk/src/trace/BUILD
 create mode 100644 sdk/src/trace/recordable.h
 create mode 100644 sdk/src/trace/recorder.h
 create mode 100644 sdk/src/trace/span.cc
 create mode 100644 sdk/src/trace/span.h
 create mode 100644 sdk/src/trace/tracer.cc
 create mode 100644 sdk/src/trace/tracer.h

diff --git a/sdk/src/opentelemetry/context/TBD b/sdk/src/context/TBD
similarity index 100%
rename from sdk/src/opentelemetry/context/TBD
rename to sdk/src/context/TBD
diff --git a/sdk/src/opentelemetry/distributedcontext/TBD b/sdk/src/distributedcontext/TBD
similarity index 100%
rename from sdk/src/opentelemetry/distributedcontext/TBD
rename to sdk/src/distributedcontext/TBD
diff --git a/sdk/src/opentelemetry/internal/TBD b/sdk/src/internal/TBD
similarity index 100%
rename from sdk/src/opentelemetry/internal/TBD
rename to sdk/src/internal/TBD
diff --git a/sdk/src/opentelemetry/logs/TBD b/sdk/src/logs/TBD
similarity index 100%
rename from sdk/src/opentelemetry/logs/TBD
rename to sdk/src/logs/TBD
diff --git a/sdk/src/opentelemetry/metrics/TBD b/sdk/src/metrics/TBD
similarity index 100%
rename from sdk/src/opentelemetry/metrics/TBD
rename to sdk/src/metrics/TBD
diff --git a/sdk/src/opentelemetry/trace/tracer_handle.h b/sdk/src/opentelemetry/trace/tracer_handle.h
deleted file mode 100644
index 15d5a29953..0000000000
--- a/sdk/src/opentelemetry/trace/tracer_handle.h
+++ /dev/null
@@ -1,27 +0,0 @@
-#pragma once
-
-#include "opentelemetry/plugin/tracer_handle.h"
-
-namespace opentelemetry
-{
-namespace sdk
-{
-namespace trace
-{
-namespace api = opentelemetry::trace;
-
-class TracerHandle final : public plugin::TracerHandle
-{
-public:
-  explicit TracerHandle(std::shared_ptr<api::Tracer> tracer) noexcept : tracer_{std::move(tracer)}
-  {}
-
-  // opentelemetry::plugin::TracerHandle
-  api::Tracer &tracer() const noexcept override { return tracer_; }
-
-private:
-  std::shared_ptr<api::Tracer> tracer_;
-};
-}  // namespace trace
-}  // namespace sdk
-}  // namespace opentelemetry
diff --git a/sdk/src/opentelemetry/resource/TBD b/sdk/src/resource/TBD
similarity index 100%
rename from sdk/src/opentelemetry/resource/TBD
rename to sdk/src/resource/TBD
diff --git a/sdk/src/trace/BUILD b/sdk/src/trace/BUILD
new file mode 100644
index 0000000000..997958e41e
--- /dev/null
+++ b/sdk/src/trace/BUILD
@@ -0,0 +1,24 @@
+# Copyright 2019, OpenTelemetry Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+package(default_visibility = ["//visibility:public"])
+
+cc_library(
+    name = "trace",
+    hdrs = glob(["**/*.h"]),
+    srcs = glob(["**/*.cc"]),
+    deps = [
+        "//api",
+    ],
+)
diff --git a/sdk/src/trace/recordable.h b/sdk/src/trace/recordable.h
new file mode 100644
index 0000000000..25a1f4ca1c
--- /dev/null
+++ b/sdk/src/trace/recordable.h
@@ -0,0 +1,29 @@
+#pragma once
+
+#include "opentelemetry/core/timestamp.h"
+#include "opentelemetry/nostd/string_view.h"
+#include "opentelemetry/trace/canonical_code.h"
+
+namespace opentelemetry
+{
+namespace sdk {
+namespace trace
+{
+namespace trace_api = opentelemetry::trace;
+
+class Recordable
+{
+public:
+  virtual ~Recordable() = default;
+
+  virtual void AddEvent(nostd::string_view name,
+                        std::chrono::nanoseconds time_since_epoch) noexcept = 0;
+
+  virtual void SetStatus(trace_api::CanonicalCode code,
+                         nostd::string_view description) noexcept = 0;
+
+  virtual void SetName(nostd::string_view name) noexcept = 0;
+};
+}  // namespace trace
+} // namespace sdk
+}  // namespace opentelemetry
diff --git a/sdk/src/trace/recorder.h b/sdk/src/trace/recorder.h
new file mode 100644
index 0000000000..9823257bea
--- /dev/null
+++ b/sdk/src/trace/recorder.h
@@ -0,0 +1,22 @@
+#pragma once
+
+#include "opentelemetry/trace/trace_id.h"
+#include "opentelemetry/trace/span_id.h"
+#include "sdk/src/trace/recordable.h"
+
+namespace opentelemetry
+{
+namespace sdk {
+namespace trace
+{
+class Recorder {
+ public:
+   virtual ~Recorder() = default;
+
+   virtual std::unique_ptr<Recordable> MakeRecordable() noexcept = 0;
+
+   virtual void Record(std::unique_ptr<Recordable>&& recordable) noexcept = 0;
+};
+}  // namespace trace
+} // namespace sdk
+}  // namespace opentelemetry
diff --git a/sdk/src/trace/span.cc b/sdk/src/trace/span.cc
new file mode 100644
index 0000000000..85254ff27e
--- /dev/null
+++ b/sdk/src/trace/span.cc
@@ -0,0 +1,19 @@
+#include "sdk/src/trace/span.h"
+
+namespace opentelemetry
+{
+namespace sdk
+{
+namespace trace
+{
+Span::Span(std::shared_ptr<Tracer> &&tracer,
+           nostd::string_view name,
+           const trace_api::StartSpanOptions &options) noexcept
+    : tracer_{std::move(tracer)}, recordable_{tracer_->recorder().MakeRecordable()}
+{
+  (void)name;
+  (void)options;
+}
+}  // namespace trace
+}  // namespace sdk
+}  // namespace opentelemetry
diff --git a/sdk/src/trace/span.h b/sdk/src/trace/span.h
new file mode 100644
index 0000000000..3ffc97e608
--- /dev/null
+++ b/sdk/src/trace/span.h
@@ -0,0 +1,25 @@
+#pragma once
+
+#include "sdk/src/trace/tracer.h"
+
+#include <mutex>
+
+namespace opentelemetry {
+namespace sdk {
+namespace trace {
+namespace trace_api = opentelemetry::trace;
+
+class Span final : public trace_api::Span {
+ public:
+   explicit Span(std::shared_ptr<Tracer> &&tracer,
+                 nostd::string_view name,
+                 const trace_api::StartSpanOptions &options) noexcept;
+
+ private:
+   std::shared_ptr<Tracer> tracer_;
+   std::mutex mutex_;
+   std::unique_ptr<Recordable> recordable_;
+};
+} // namespace trace
+} // namespace sdk
+} // namespace opentelemetry
diff --git a/sdk/src/trace/tracer.cc b/sdk/src/trace/tracer.cc
new file mode 100644
index 0000000000..18808f19d2
--- /dev/null
+++ b/sdk/src/trace/tracer.cc
@@ -0,0 +1,19 @@
+#include "sdk/src/trace/tracer.h"
+
+namespace opentelemetry
+{
+namespace sdk
+{
+namespace trace
+{
+nostd::unique_ptr<trace_api::Span> Tracer::StartSpan(
+    nostd::string_view name,
+    const trace_api::StartSpanOptions &options) noexcept
+{
+  (void)name;
+  (void)options;
+  return nullptr;
+}
+}  // namespace trace
+}  // namespace sdk
+}  // namespace opentelemetry
diff --git a/sdk/src/trace/tracer.h b/sdk/src/trace/tracer.h
new file mode 100644
index 0000000000..aee93ab45f
--- /dev/null
+++ b/sdk/src/trace/tracer.h
@@ -0,0 +1,28 @@
+#pragma once
+
+#include "opentelemetry/trace/tracer.h"
+#include "sdk/src/trace/recorder.h"
+
+#include <memory>
+
+namespace opentelemetry {
+namespace sdk {
+namespace trace {
+class Tracer final : public trace_api::Tracer, public std::enable_shared_from_this<Tracer>
+{
+public:
+  explicit Tracer(std::unique_ptr<Recorder> &&recorder) noexcept : recorder_{std::move(recorder)} {}
+
+  Recorder &recorder() const noexcept { return *recorder_; }
+
+  // trace_api::Tracer
+  nostd::unique_ptr<trace_api::Span> StartSpan(
+      nostd::string_view name,
+      const trace_api::StartSpanOptions &options = {}) noexcept override;
+
+private:
+  std::unique_ptr<Recorder> recorder_;
+};
+} // namespace trace
+} // namespace sdk
+} // namespace opentelemetry

From 79b4f1d5cf546312090f734835b6a623f0d7759d Mon Sep 17 00:00:00 2001
From: Ryan Burn <ryan.burn@gmail.com>
Date: Mon, 2 Mar 2020 23:43:52 -0800
Subject: [PATCH 02/17] Fill out Span api

---
 sdk/src/trace/span.cc | 35 +++++++++++++++++++++++++++++++
 sdk/src/trace/span.h  | 49 ++++++++++++++++++++++++++++++-------------
 2 files changed, 69 insertions(+), 15 deletions(-)

diff --git a/sdk/src/trace/span.cc b/sdk/src/trace/span.cc
index 85254ff27e..533745e56b 100644
--- a/sdk/src/trace/span.cc
+++ b/sdk/src/trace/span.cc
@@ -14,6 +14,41 @@ Span::Span(std::shared_ptr<Tracer> &&tracer,
   (void)name;
   (void)options;
 }
+
+void Span::AddEvent(nostd::string_view name) noexcept
+{
+  (void)name;
+}
+
+void Span::AddEvent(nostd::string_view name, core::SystemTimestamp timestamp) noexcept
+{
+  (void)name;
+  (void)timestamp;
+}
+
+void Span::AddEvent(nostd::string_view name, core::SteadyTimestamp timestamp) noexcept
+{
+  (void)name;
+  (void)timestamp;
+}
+
+void Span::SetStatus(trace_api::CanonicalCode code, nostd::string_view description) noexcept
+{
+  (void)code;
+  (void)description;
+}
+
+void Span::UpdateName(nostd::string_view name) noexcept
+{
+  (void)name;
+}
+
+void Span::End() noexcept {}
+
+bool Span::IsRecording() const noexcept
+{
+  return true;
+}
 }  // namespace trace
 }  // namespace sdk
 }  // namespace opentelemetry
diff --git a/sdk/src/trace/span.h b/sdk/src/trace/span.h
index 3ffc97e608..5240562c3b 100644
--- a/sdk/src/trace/span.h
+++ b/sdk/src/trace/span.h
@@ -4,22 +4,41 @@
 
 #include <mutex>
 
-namespace opentelemetry {
-namespace sdk {
-namespace trace {
+namespace opentelemetry
+{
+namespace sdk
+{
+namespace trace
+{
 namespace trace_api = opentelemetry::trace;
 
-class Span final : public trace_api::Span {
- public:
-   explicit Span(std::shared_ptr<Tracer> &&tracer,
-                 nostd::string_view name,
-                 const trace_api::StartSpanOptions &options) noexcept;
+class Span final : public trace_api::Span
+{
+public:
+  explicit Span(std::shared_ptr<Tracer> &&tracer,
+                nostd::string_view name,
+                const trace_api::StartSpanOptions &options) noexcept;
 
- private:
-   std::shared_ptr<Tracer> tracer_;
-   std::mutex mutex_;
-   std::unique_ptr<Recordable> recordable_;
+  void AddEvent(nostd::string_view name) noexcept override;
+
+  void AddEvent(nostd::string_view name, core::SystemTimestamp timestamp) noexcept override;
+  void AddEvent(nostd::string_view name, core::SteadyTimestamp timestamp) noexcept override;
+
+  void SetStatus(trace_api::CanonicalCode code, nostd::string_view description) noexcept override;
+
+  void UpdateName(nostd::string_view name) noexcept override;
+
+  void End() noexcept override;
+
+  bool IsRecording() const noexcept override;
+
+  trace_api::Tracer &tracer() const noexcept override { return *tracer_; }
+
+private:
+  std::shared_ptr<Tracer> tracer_;
+  std::mutex mutex_;
+  std::unique_ptr<Recordable> recordable_;
 };
-} // namespace trace
-} // namespace sdk
-} // namespace opentelemetry
+}  // namespace trace
+}  // namespace sdk
+}  // namespace opentelemetry

From 8bcff6e424025cc910bca24234a174c57cee2040 Mon Sep 17 00:00:00 2001
From: Ryan Burn <ryan.burn@gmail.com>
Date: Tue, 3 Mar 2020 00:06:29 -0800
Subject: [PATCH 03/17] Reformat

---
 sdk/src/trace/span.cc | 23 ++++++++++++++++++++---
 1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/sdk/src/trace/span.cc b/sdk/src/trace/span.cc
index 533745e56b..8fd220e773 100644
--- a/sdk/src/trace/span.cc
+++ b/sdk/src/trace/span.cc
@@ -11,8 +11,11 @@ Span::Span(std::shared_ptr<Tracer> &&tracer,
            const trace_api::StartSpanOptions &options) noexcept
     : tracer_{std::move(tracer)}, recordable_{tracer_->recorder().MakeRecordable()}
 {
-  (void)name;
   (void)options;
+  if (recordable_ == nullptr) {
+    return;
+  }
+  recordable_->SetName(name);
 }
 
 void Span::AddEvent(nostd::string_view name) noexcept
@@ -40,10 +43,24 @@ void Span::SetStatus(trace_api::CanonicalCode code, nostd::string_view descripti
 
 void Span::UpdateName(nostd::string_view name) noexcept
 {
-  (void)name;
+  std::lock_guard<std::mutex> lock_guard{mutex_};
+  if (recordable_ == nullptr)
+  {
+    return;
+  }
+  recordable_->SetName(name);
 }
 
-void Span::End() noexcept {}
+void Span::End() noexcept
+{
+  std::lock_guard<std::mutex> lock_guard{mutex_};
+  if (recordable_ == nullptr)
+  {
+    return;
+  }
+  tracer_->recorder().Record(std::move(recordable_));
+  recordable_.reset();
+}
 
 bool Span::IsRecording() const noexcept
 {

From c5e9a9e53357a0282edf3752a0624a5e5c8129d8 Mon Sep 17 00:00:00 2001
From: Ryan Burn <ryan.burn@gmail.com>
Date: Tue, 3 Mar 2020 13:43:27 -0800
Subject: [PATCH 04/17] Fill out Tracer class

---
 sdk/src/trace/span.cc   | 12 ++++++++++--
 sdk/src/trace/span.h    |  2 ++
 sdk/src/trace/tracer.cc |  7 ++++---
 3 files changed, 16 insertions(+), 5 deletions(-)

diff --git a/sdk/src/trace/span.cc b/sdk/src/trace/span.cc
index 8fd220e773..726d63c7f5 100644
--- a/sdk/src/trace/span.cc
+++ b/sdk/src/trace/span.cc
@@ -18,6 +18,10 @@ Span::Span(std::shared_ptr<Tracer> &&tracer,
   recordable_->SetName(name);
 }
 
+Span::~Span() {
+  End();
+}
+
 void Span::AddEvent(nostd::string_view name) noexcept
 {
   (void)name;
@@ -37,8 +41,12 @@ void Span::AddEvent(nostd::string_view name, core::SteadyTimestamp timestamp) no
 
 void Span::SetStatus(trace_api::CanonicalCode code, nostd::string_view description) noexcept
 {
-  (void)code;
-  (void)description;
+  std::lock_guard<std::mutex> lock_guard{mutex_};
+  if (recordable_ == nullptr)
+  {
+    return;
+  }
+  recordable_->SetStatus(code, description);
 }
 
 void Span::UpdateName(nostd::string_view name) noexcept
diff --git a/sdk/src/trace/span.h b/sdk/src/trace/span.h
index 5240562c3b..8eb6fb178b 100644
--- a/sdk/src/trace/span.h
+++ b/sdk/src/trace/span.h
@@ -19,6 +19,8 @@ class Span final : public trace_api::Span
                 nostd::string_view name,
                 const trace_api::StartSpanOptions &options) noexcept;
 
+  ~Span() override;
+
   void AddEvent(nostd::string_view name) noexcept override;
 
   void AddEvent(nostd::string_view name, core::SystemTimestamp timestamp) noexcept override;
diff --git a/sdk/src/trace/tracer.cc b/sdk/src/trace/tracer.cc
index 18808f19d2..a923f17133 100644
--- a/sdk/src/trace/tracer.cc
+++ b/sdk/src/trace/tracer.cc
@@ -1,5 +1,7 @@
 #include "sdk/src/trace/tracer.h"
 
+#include "sdk/src/trace/span.h"
+
 namespace opentelemetry
 {
 namespace sdk
@@ -10,9 +12,8 @@ nostd::unique_ptr<trace_api::Span> Tracer::StartSpan(
     nostd::string_view name,
     const trace_api::StartSpanOptions &options) noexcept
 {
-  (void)name;
-  (void)options;
-  return nullptr;
+  return nostd::unique_ptr<trace_api::Span>{new (std::nothrow)
+                                                Span{this->shared_from_this(), name, options}};
 }
 }  // namespace trace
 }  // namespace sdk

From a69206f70c1dd33bfc2cc3c71ecb0e901a870729 Mon Sep 17 00:00:00 2001
From: Ryan Burn <ryan.burn@gmail.com>
Date: Tue, 3 Mar 2020 16:58:34 -0800
Subject: [PATCH 05/17] Add cmake build

---
 CMakeLists.txt               | 3 +++
 sdk/src/trace/BUILD          | 1 +
 sdk/src/trace/CMakeLists.txt | 3 +++
 sdk/src/trace/recorder.h     | 2 +-
 sdk/src/trace/span.cc        | 2 +-
 sdk/src/trace/span.h         | 2 +-
 sdk/src/trace/tracer.cc      | 4 ++--
 sdk/src/trace/tracer.h       | 2 +-
 8 files changed, 13 insertions(+), 6 deletions(-)
 create mode 100644 sdk/src/trace/CMakeLists.txt

diff --git a/CMakeLists.txt b/CMakeLists.txt
index c34736db49..c10f92d39d 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -20,4 +20,7 @@ endif()
 
 include_directories(api/include)
 add_subdirectory(api)
+include_directories(sdk/include)
+include_directories(sdk)
+add_subdirectory(sdk)
 add_subdirectory(examples)
diff --git a/sdk/src/trace/BUILD b/sdk/src/trace/BUILD
index 997958e41e..540fc8fccb 100644
--- a/sdk/src/trace/BUILD
+++ b/sdk/src/trace/BUILD
@@ -21,4 +21,5 @@ cc_library(
     deps = [
         "//api",
     ],
+    include_prefix = "src/trace",
 )
diff --git a/sdk/src/trace/CMakeLists.txt b/sdk/src/trace/CMakeLists.txt
new file mode 100644
index 0000000000..e2ec1f99cb
--- /dev/null
+++ b/sdk/src/trace/CMakeLists.txt
@@ -0,0 +1,3 @@
+add_library(opentelemetry_trace
+      tracer.cc
+      span.cc)
diff --git a/sdk/src/trace/recorder.h b/sdk/src/trace/recorder.h
index 9823257bea..c22f443c0a 100644
--- a/sdk/src/trace/recorder.h
+++ b/sdk/src/trace/recorder.h
@@ -2,7 +2,7 @@
 
 #include "opentelemetry/trace/trace_id.h"
 #include "opentelemetry/trace/span_id.h"
-#include "sdk/src/trace/recordable.h"
+#include "src/trace/recordable.h"
 
 namespace opentelemetry
 {
diff --git a/sdk/src/trace/span.cc b/sdk/src/trace/span.cc
index 726d63c7f5..3711ef5c90 100644
--- a/sdk/src/trace/span.cc
+++ b/sdk/src/trace/span.cc
@@ -1,4 +1,4 @@
-#include "sdk/src/trace/span.h"
+#include "src/trace/span.h"
 
 namespace opentelemetry
 {
diff --git a/sdk/src/trace/span.h b/sdk/src/trace/span.h
index 8eb6fb178b..8978cd3f83 100644
--- a/sdk/src/trace/span.h
+++ b/sdk/src/trace/span.h
@@ -1,6 +1,6 @@
 #pragma once
 
-#include "sdk/src/trace/tracer.h"
+#include "src/trace/tracer.h"
 
 #include <mutex>
 
diff --git a/sdk/src/trace/tracer.cc b/sdk/src/trace/tracer.cc
index a923f17133..824c560cfe 100644
--- a/sdk/src/trace/tracer.cc
+++ b/sdk/src/trace/tracer.cc
@@ -1,6 +1,6 @@
-#include "sdk/src/trace/tracer.h"
+#include "src/trace/tracer.h"
 
-#include "sdk/src/trace/span.h"
+#include "src/trace/span.h"
 
 namespace opentelemetry
 {
diff --git a/sdk/src/trace/tracer.h b/sdk/src/trace/tracer.h
index aee93ab45f..1f542770d6 100644
--- a/sdk/src/trace/tracer.h
+++ b/sdk/src/trace/tracer.h
@@ -1,7 +1,7 @@
 #pragma once
 
 #include "opentelemetry/trace/tracer.h"
-#include "sdk/src/trace/recorder.h"
+#include "src/trace/recorder.h"
 
 #include <memory>
 

From 87170e32f734bb1dfc62c06048c143f92023de02 Mon Sep 17 00:00:00 2001
From: Ryan Burn <ryan.burn@gmail.com>
Date: Tue, 3 Mar 2020 17:14:54 -0800
Subject: [PATCH 06/17] Add commenting

---
 sdk/CMakeLists.txt         |  1 +
 sdk/src/CMakeLists.txt     |  1 +
 sdk/src/trace/recordable.h | 22 ++++++++++++++++++++--
 sdk/src/trace/recorder.h   | 25 +++++++++++++++++--------
 4 files changed, 39 insertions(+), 10 deletions(-)
 create mode 100644 sdk/CMakeLists.txt
 create mode 100644 sdk/src/CMakeLists.txt

diff --git a/sdk/CMakeLists.txt b/sdk/CMakeLists.txt
new file mode 100644
index 0000000000..febd4f0ab6
--- /dev/null
+++ b/sdk/CMakeLists.txt
@@ -0,0 +1 @@
+add_subdirectory(src)
diff --git a/sdk/src/CMakeLists.txt b/sdk/src/CMakeLists.txt
new file mode 100644
index 0000000000..2cea47fa7b
--- /dev/null
+++ b/sdk/src/CMakeLists.txt
@@ -0,0 +1 @@
+add_subdirectory(trace)
diff --git a/sdk/src/trace/recordable.h b/sdk/src/trace/recordable.h
index 25a1f4ca1c..a1dd5bd7c0 100644
--- a/sdk/src/trace/recordable.h
+++ b/sdk/src/trace/recordable.h
@@ -6,24 +6,42 @@
 
 namespace opentelemetry
 {
-namespace sdk {
+namespace sdk
+{
 namespace trace
 {
 namespace trace_api = opentelemetry::trace;
 
+/**
+ * Maintains a representation of a span in a format that can be processed by a recroder.
+ */
 class Recordable
 {
 public:
   virtual ~Recordable() = default;
 
+  /**
+   * Add an event to a span.
+   * @param name the name of the event
+   * @param time_since_epoch the timestamp of the event
+   */
   virtual void AddEvent(nostd::string_view name,
                         std::chrono::nanoseconds time_since_epoch) noexcept = 0;
 
+  /**
+   * Set the status of the span.
+   * @param code the status code
+   * @param description a description of the status
+   */
   virtual void SetStatus(trace_api::CanonicalCode code,
                          nostd::string_view description) noexcept = 0;
 
+  /**
+   * Set the name of the span.
+   * @param name the name to set
+   */
   virtual void SetName(nostd::string_view name) noexcept = 0;
 };
 }  // namespace trace
-} // namespace sdk
+}  // namespace sdk
 }  // namespace opentelemetry
diff --git a/sdk/src/trace/recorder.h b/sdk/src/trace/recorder.h
index c22f443c0a..c228453769 100644
--- a/sdk/src/trace/recorder.h
+++ b/sdk/src/trace/recorder.h
@@ -1,22 +1,31 @@
 #pragma once
 
-#include "opentelemetry/trace/trace_id.h"
 #include "opentelemetry/trace/span_id.h"
+#include "opentelemetry/trace/trace_id.h"
 #include "src/trace/recordable.h"
 
 namespace opentelemetry
 {
-namespace sdk {
+namespace sdk
+{
 namespace trace
 {
-class Recorder {
- public:
-   virtual ~Recorder() = default;
+class Recorder
+{
+public:
+  virtual ~Recorder() = default;
 
-   virtual std::unique_ptr<Recordable> MakeRecordable() noexcept = 0;
+  /**
+   * @return a Recordable object to maintain a data representation of a span.
+   */
+  virtual std::unique_ptr<Recordable> MakeRecordable() noexcept = 0;
 
-   virtual void Record(std::unique_ptr<Recordable>&& recordable) noexcept = 0;
+  /**
+   * Record a span.
+   * @param recordable the data representation of the span.
+   */
+  virtual void Record(std::unique_ptr<Recordable> &&recordable) noexcept = 0;
 };
 }  // namespace trace
-} // namespace sdk
+}  // namespace sdk
 }  // namespace opentelemetry

From 320add049b1d4efef0af833e14b1e10038dfdb95 Mon Sep 17 00:00:00 2001
From: Ryan Burn <ryan.burn@gmail.com>
Date: Tue, 3 Mar 2020 17:55:08 -0800
Subject: [PATCH 07/17] Fix formatting

---
 api/include/opentelemetry/plugin/detail/utility.h |  2 +-
 api/test/nostd/unique_ptr_test.cc                 |  3 +--
 sdk/src/trace/BUILD                               |  4 ++--
 sdk/src/trace/CMakeLists.txt                      |  4 +---
 sdk/src/trace/span.cc                             |  6 ++++--
 sdk/src/trace/tracer.h                            | 15 +++++++++------
 6 files changed, 18 insertions(+), 16 deletions(-)

diff --git a/api/include/opentelemetry/plugin/detail/utility.h b/api/include/opentelemetry/plugin/detail/utility.h
index 5d85f182ec..743ca54f6b 100644
--- a/api/include/opentelemetry/plugin/detail/utility.h
+++ b/api/include/opentelemetry/plugin/detail/utility.h
@@ -13,7 +13,7 @@ namespace detail
 {
 inline void CopyErrorMessage(const char *source, std::string &destination) noexcept
 #if __EXCEPTIONS
-try
+    try
 #endif
 {
   if (source == nullptr)
diff --git a/api/test/nostd/unique_ptr_test.cc b/api/test/nostd/unique_ptr_test.cc
index ee1ae17f4a..521e8e16dc 100644
--- a/api/test/nostd/unique_ptr_test.cc
+++ b/api/test/nostd/unique_ptr_test.cc
@@ -108,8 +108,7 @@ TEST(UniquePtrTest, PointerOperators)
   unique_ptr<int> ptr1{value};
 
   EXPECT_EQ(&*ptr1, value);
-  EXPECT_EQ(
-      unique_ptr<B> {}->f(), 123);
+  EXPECT_EQ(unique_ptr<B> {}->f(), 123);
 }
 
 TEST(UniquePtrTest, Reset)
diff --git a/sdk/src/trace/BUILD b/sdk/src/trace/BUILD
index 540fc8fccb..3db5430e49 100644
--- a/sdk/src/trace/BUILD
+++ b/sdk/src/trace/BUILD
@@ -16,10 +16,10 @@ package(default_visibility = ["//visibility:public"])
 
 cc_library(
     name = "trace",
-    hdrs = glob(["**/*.h"]),
     srcs = glob(["**/*.cc"]),
+    hdrs = glob(["**/*.h"]),
+    include_prefix = "src/trace",
     deps = [
         "//api",
     ],
-    include_prefix = "src/trace",
 )
diff --git a/sdk/src/trace/CMakeLists.txt b/sdk/src/trace/CMakeLists.txt
index e2ec1f99cb..62a2187c46 100644
--- a/sdk/src/trace/CMakeLists.txt
+++ b/sdk/src/trace/CMakeLists.txt
@@ -1,3 +1 @@
-add_library(opentelemetry_trace
-      tracer.cc
-      span.cc)
+add_library(opentelemetry_trace tracer.cc span.cc)
diff --git a/sdk/src/trace/span.cc b/sdk/src/trace/span.cc
index 3711ef5c90..5ba7dc5275 100644
--- a/sdk/src/trace/span.cc
+++ b/sdk/src/trace/span.cc
@@ -12,13 +12,15 @@ Span::Span(std::shared_ptr<Tracer> &&tracer,
     : tracer_{std::move(tracer)}, recordable_{tracer_->recorder().MakeRecordable()}
 {
   (void)options;
-  if (recordable_ == nullptr) {
+  if (recordable_ == nullptr)
+  {
     return;
   }
   recordable_->SetName(name);
 }
 
-Span::~Span() {
+Span::~Span()
+{
   End();
 }
 
diff --git a/sdk/src/trace/tracer.h b/sdk/src/trace/tracer.h
index 1f542770d6..2540c35647 100644
--- a/sdk/src/trace/tracer.h
+++ b/sdk/src/trace/tracer.h
@@ -5,9 +5,12 @@
 
 #include <memory>
 
-namespace opentelemetry {
-namespace sdk {
-namespace trace {
+namespace opentelemetry
+{
+namespace sdk
+{
+namespace trace
+{
 class Tracer final : public trace_api::Tracer, public std::enable_shared_from_this<Tracer>
 {
 public:
@@ -23,6 +26,6 @@ class Tracer final : public trace_api::Tracer, public std::enable_shared_from_th
 private:
   std::unique_ptr<Recorder> recorder_;
 };
-} // namespace trace
-} // namespace sdk
-} // namespace opentelemetry
+}  // namespace trace
+}  // namespace sdk
+}  // namespace opentelemetry

From 1a3761e4187aadcda2679a3d480604deb661edc4 Mon Sep 17 00:00:00 2001
From: Ryan Burn <ryan.burn@gmail.com>
Date: Tue, 3 Mar 2020 17:59:03 -0800
Subject: [PATCH 08/17] Reformat

---
 api/include/opentelemetry/plugin/detail/utility.h | 2 +-
 api/test/nostd/unique_ptr_test.cc                 | 3 ++-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/api/include/opentelemetry/plugin/detail/utility.h b/api/include/opentelemetry/plugin/detail/utility.h
index 743ca54f6b..5d85f182ec 100644
--- a/api/include/opentelemetry/plugin/detail/utility.h
+++ b/api/include/opentelemetry/plugin/detail/utility.h
@@ -13,7 +13,7 @@ namespace detail
 {
 inline void CopyErrorMessage(const char *source, std::string &destination) noexcept
 #if __EXCEPTIONS
-    try
+try
 #endif
 {
   if (source == nullptr)
diff --git a/api/test/nostd/unique_ptr_test.cc b/api/test/nostd/unique_ptr_test.cc
index 521e8e16dc..ee1ae17f4a 100644
--- a/api/test/nostd/unique_ptr_test.cc
+++ b/api/test/nostd/unique_ptr_test.cc
@@ -108,7 +108,8 @@ TEST(UniquePtrTest, PointerOperators)
   unique_ptr<int> ptr1{value};
 
   EXPECT_EQ(&*ptr1, value);
-  EXPECT_EQ(unique_ptr<B> {}->f(), 123);
+  EXPECT_EQ(
+      unique_ptr<B> {}->f(), 123);
 }
 
 TEST(UniquePtrTest, Reset)

From 597f0f37c1be91d73bcfe4e77949c30ff00c0217 Mon Sep 17 00:00:00 2001
From: Ryan Burn <ryan.burn@gmail.com>
Date: Tue, 3 Mar 2020 18:29:00 -0800
Subject: [PATCH 09/17] Fix date

---
 sdk/src/trace/BUILD | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sdk/src/trace/BUILD b/sdk/src/trace/BUILD
index 3db5430e49..f990c57425 100644
--- a/sdk/src/trace/BUILD
+++ b/sdk/src/trace/BUILD
@@ -1,4 +1,4 @@
-# Copyright 2019, OpenTelemetry Authors
+# Copyright 2020, OpenTelemetry Authors
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.

From 0d8649f74c5a5d89e3e86cd4cd29e603ca1fe592 Mon Sep 17 00:00:00 2001
From: Ryan Burn <ryan.burn@gmail.com>
Date: Tue, 3 Mar 2020 18:29:11 -0800
Subject: [PATCH 10/17] Make mutex mutable

---
 sdk/src/trace/span.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sdk/src/trace/span.h b/sdk/src/trace/span.h
index 8978cd3f83..470406b410 100644
--- a/sdk/src/trace/span.h
+++ b/sdk/src/trace/span.h
@@ -38,7 +38,7 @@ class Span final : public trace_api::Span
 
 private:
   std::shared_ptr<Tracer> tracer_;
-  std::mutex mutex_;
+  mutable std::mutex mutex_;
   std::unique_ptr<Recordable> recordable_;
 };
 }  // namespace trace

From c15286ecc4ded4657c42d9cc08eaea23e7659c5a Mon Sep 17 00:00:00 2001
From: Ryan Burn <ryan.burn@gmail.com>
Date: Tue, 3 Mar 2020 19:01:48 -0800
Subject: [PATCH 11/17] s/mutex_/mu_/

---
 sdk/src/trace/span.cc | 6 +++---
 sdk/src/trace/span.h  | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/sdk/src/trace/span.cc b/sdk/src/trace/span.cc
index 5ba7dc5275..7009a964a8 100644
--- a/sdk/src/trace/span.cc
+++ b/sdk/src/trace/span.cc
@@ -43,7 +43,7 @@ void Span::AddEvent(nostd::string_view name, core::SteadyTimestamp timestamp) no
 
 void Span::SetStatus(trace_api::CanonicalCode code, nostd::string_view description) noexcept
 {
-  std::lock_guard<std::mutex> lock_guard{mutex_};
+  std::lock_guard<std::mutex> lock_guard{mu_};
   if (recordable_ == nullptr)
   {
     return;
@@ -53,7 +53,7 @@ void Span::SetStatus(trace_api::CanonicalCode code, nostd::string_view descripti
 
 void Span::UpdateName(nostd::string_view name) noexcept
 {
-  std::lock_guard<std::mutex> lock_guard{mutex_};
+  std::lock_guard<std::mutex> lock_guard{mu_};
   if (recordable_ == nullptr)
   {
     return;
@@ -63,7 +63,7 @@ void Span::UpdateName(nostd::string_view name) noexcept
 
 void Span::End() noexcept
 {
-  std::lock_guard<std::mutex> lock_guard{mutex_};
+  std::lock_guard<std::mutex> lock_guard{mu_};
   if (recordable_ == nullptr)
   {
     return;
diff --git a/sdk/src/trace/span.h b/sdk/src/trace/span.h
index 470406b410..f70d7d5e98 100644
--- a/sdk/src/trace/span.h
+++ b/sdk/src/trace/span.h
@@ -38,7 +38,7 @@ class Span final : public trace_api::Span
 
 private:
   std::shared_ptr<Tracer> tracer_;
-  mutable std::mutex mutex_;
+  mutable std::mutex mu_;
   std::unique_ptr<Recordable> recordable_;
 };
 }  // namespace trace

From 3c6fbb060a55ae6ac2b074d3bc3d3b9d8ec48b55 Mon Sep 17 00:00:00 2001
From: Ryan Burn <ryan.burn@gmail.com>
Date: Thu, 5 Mar 2020 15:10:10 -0800
Subject: [PATCH 12/17] Remove AddEvent with steady timestamp

---
 api/include/opentelemetry/plugin/tracer.h | 4 ----
 api/include/opentelemetry/trace/noop.h    | 1 -
 api/include/opentelemetry/trace/span.h    | 1 -
 examples/plugin/plugin/tracer.cc          | 2 --
 sdk/src/trace/recordable.h                | 5 ++---
 sdk/src/trace/span.cc                     | 6 ------
 sdk/src/trace/span.h                      | 1 -
 7 files changed, 2 insertions(+), 18 deletions(-)

diff --git a/api/include/opentelemetry/plugin/tracer.h b/api/include/opentelemetry/plugin/tracer.h
index d9a68800df..76cd8249c8 100644
--- a/api/include/opentelemetry/plugin/tracer.h
+++ b/api/include/opentelemetry/plugin/tracer.h
@@ -24,10 +24,6 @@ class Span final : public trace::Span
   {
     span_->AddEvent(name, timestamp);
   }
-  void AddEvent(nostd::string_view name, core::SteadyTimestamp timestamp) noexcept override
-  {
-    span_->AddEvent(name, timestamp);
-  }
 
   void SetStatus(trace::CanonicalCode code, nostd::string_view description) noexcept override
   {
diff --git a/api/include/opentelemetry/trace/noop.h b/api/include/opentelemetry/trace/noop.h
index 60deddbf93..bef4cf8fc8 100644
--- a/api/include/opentelemetry/trace/noop.h
+++ b/api/include/opentelemetry/trace/noop.h
@@ -26,7 +26,6 @@ class NoopSpan final : public Span
   void AddEvent(nostd::string_view name) noexcept override {}
 
   void AddEvent(nostd::string_view name, core::SystemTimestamp timestamp) noexcept override {}
-  void AddEvent(nostd::string_view name, core::SteadyTimestamp timestamp) noexcept override {}
 
   void SetStatus(CanonicalCode code, nostd::string_view description) noexcept override {}
 
diff --git a/api/include/opentelemetry/trace/span.h b/api/include/opentelemetry/trace/span.h
index 300ec0478d..79d31d0cec 100644
--- a/api/include/opentelemetry/trace/span.h
+++ b/api/include/opentelemetry/trace/span.h
@@ -76,7 +76,6 @@ class Span
 
   // Adds an event to the Span, with a custom timestamp.
   virtual void AddEvent(nostd::string_view name, core::SystemTimestamp timestamp) noexcept = 0;
-  virtual void AddEvent(nostd::string_view name, core::SteadyTimestamp timestamp) noexcept = 0;
 
   // TODO
   // Adds an event to the Span, with a custom timestamp, and attributes.
diff --git a/examples/plugin/plugin/tracer.cc b/examples/plugin/plugin/tracer.cc
index 02a828e0fa..5a0c861ea6 100644
--- a/examples/plugin/plugin/tracer.cc
+++ b/examples/plugin/plugin/tracer.cc
@@ -26,8 +26,6 @@ class Span final : public trace::Span
 
   void AddEvent(nostd::string_view /*name*/, core::SystemTimestamp /*timestamp*/) noexcept override
   {}
-  void AddEvent(nostd::string_view /*name*/, core::SteadyTimestamp /*timestamp*/) noexcept override
-  {}
 
   void SetStatus(trace::CanonicalCode /*code*/,
                  nostd::string_view /*description*/) noexcept override
diff --git a/sdk/src/trace/recordable.h b/sdk/src/trace/recordable.h
index a1dd5bd7c0..7335315a80 100644
--- a/sdk/src/trace/recordable.h
+++ b/sdk/src/trace/recordable.h
@@ -23,10 +23,9 @@ class Recordable
   /**
    * Add an event to a span.
    * @param name the name of the event
-   * @param time_since_epoch the timestamp of the event
+   * @param timestamp the timestamp of the event
    */
-  virtual void AddEvent(nostd::string_view name,
-                        std::chrono::nanoseconds time_since_epoch) noexcept = 0;
+  virtual void AddEvent(nostd::string_view name, core::SystemTimestamp timestamp) noexcept = 0;
 
   /**
    * Set the status of the span.
diff --git a/sdk/src/trace/span.cc b/sdk/src/trace/span.cc
index 7009a964a8..82be75d51e 100644
--- a/sdk/src/trace/span.cc
+++ b/sdk/src/trace/span.cc
@@ -35,12 +35,6 @@ void Span::AddEvent(nostd::string_view name, core::SystemTimestamp timestamp) no
   (void)timestamp;
 }
 
-void Span::AddEvent(nostd::string_view name, core::SteadyTimestamp timestamp) noexcept
-{
-  (void)name;
-  (void)timestamp;
-}
-
 void Span::SetStatus(trace_api::CanonicalCode code, nostd::string_view description) noexcept
 {
   std::lock_guard<std::mutex> lock_guard{mu_};
diff --git a/sdk/src/trace/span.h b/sdk/src/trace/span.h
index f70d7d5e98..eccfd2a912 100644
--- a/sdk/src/trace/span.h
+++ b/sdk/src/trace/span.h
@@ -24,7 +24,6 @@ class Span final : public trace_api::Span
   void AddEvent(nostd::string_view name) noexcept override;
 
   void AddEvent(nostd::string_view name, core::SystemTimestamp timestamp) noexcept override;
-  void AddEvent(nostd::string_view name, core::SteadyTimestamp timestamp) noexcept override;
 
   void SetStatus(trace_api::CanonicalCode code, nostd::string_view description) noexcept override;
 

From b0d1548688d148b79ae8582e251c845b9b169771 Mon Sep 17 00:00:00 2001
From: Ryan Burn <ryan.burn@gmail.com>
Date: Thu, 5 Mar 2020 21:53:31 -0800
Subject: [PATCH 13/17] Fix typo

---
 sdk/src/trace/recordable.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sdk/src/trace/recordable.h b/sdk/src/trace/recordable.h
index 7335315a80..c342a63e18 100644
--- a/sdk/src/trace/recordable.h
+++ b/sdk/src/trace/recordable.h
@@ -13,7 +13,7 @@ namespace trace
 namespace trace_api = opentelemetry::trace;
 
 /**
- * Maintains a representation of a span in a format that can be processed by a recroder.
+ * Maintains a representation of a span in a format that can be processed by a recorder.
  */
 class Recordable
 {

From 6210da020953b7b542076240baf02de462cc1806 Mon Sep 17 00:00:00 2001
From: Ryan Burn <ryan.burn@gmail.com>
Date: Thu, 5 Mar 2020 21:55:10 -0800
Subject: [PATCH 14/17] Fill in IsRecordable

---
 sdk/src/trace/span.cc | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/sdk/src/trace/span.cc b/sdk/src/trace/span.cc
index 82be75d51e..df869640e0 100644
--- a/sdk/src/trace/span.cc
+++ b/sdk/src/trace/span.cc
@@ -68,7 +68,8 @@ void Span::End() noexcept
 
 bool Span::IsRecording() const noexcept
 {
-  return true;
+  std::lock_guard<std::mutex> lock_guard{mu_};
+  return recordable_ != nullptr;
 }
 }  // namespace trace
 }  // namespace sdk

From 36748e44a06a5b19d1d7956d4292c2c84a050f57 Mon Sep 17 00:00:00 2001
From: Ryan Burn <ryan.burn@gmail.com>
Date: Thu, 12 Mar 2020 15:51:47 -0700
Subject: [PATCH 15/17] Use namespace macros

---
 sdk/src/trace/recordable.h | 6 +++---
 sdk/src/trace/recorder.h   | 6 +++---
 sdk/src/trace/span.cc      | 7 ++++---
 sdk/src/trace/span.h       | 6 +++---
 sdk/src/trace/tracer.cc    | 6 +++---
 sdk/src/trace/tracer.h     | 6 +++---
 6 files changed, 19 insertions(+), 18 deletions(-)

diff --git a/sdk/src/trace/recordable.h b/sdk/src/trace/recordable.h
index c342a63e18..8bca640c91 100644
--- a/sdk/src/trace/recordable.h
+++ b/sdk/src/trace/recordable.h
@@ -3,9 +3,9 @@
 #include "opentelemetry/core/timestamp.h"
 #include "opentelemetry/nostd/string_view.h"
 #include "opentelemetry/trace/canonical_code.h"
+#include "opentelemetry/version.h"
 
-namespace opentelemetry
-{
+OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace trace
@@ -43,4 +43,4 @@ class Recordable
 };
 }  // namespace trace
 }  // namespace sdk
-}  // namespace opentelemetry
+OPENTELEMETRY_END_NAMESPACE
diff --git a/sdk/src/trace/recorder.h b/sdk/src/trace/recorder.h
index c228453769..b701c113d6 100644
--- a/sdk/src/trace/recorder.h
+++ b/sdk/src/trace/recorder.h
@@ -2,10 +2,10 @@
 
 #include "opentelemetry/trace/span_id.h"
 #include "opentelemetry/trace/trace_id.h"
+#include "opentelemetry/version.h"
 #include "src/trace/recordable.h"
 
-namespace opentelemetry
-{
+OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace trace
@@ -28,4 +28,4 @@ class Recorder
 };
 }  // namespace trace
 }  // namespace sdk
-}  // namespace opentelemetry
+OPENTELEMETRY_END_NAMESPACE
diff --git a/sdk/src/trace/span.cc b/sdk/src/trace/span.cc
index df869640e0..54fde5d81d 100644
--- a/sdk/src/trace/span.cc
+++ b/sdk/src/trace/span.cc
@@ -1,7 +1,8 @@
 #include "src/trace/span.h"
 
-namespace opentelemetry
-{
+#include "opentelemetry/version.h"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace trace
@@ -73,4 +74,4 @@ bool Span::IsRecording() const noexcept
 }
 }  // namespace trace
 }  // namespace sdk
-}  // namespace opentelemetry
+OPENTELEMETRY_END_NAMESPACE
diff --git a/sdk/src/trace/span.h b/sdk/src/trace/span.h
index eccfd2a912..6d40019882 100644
--- a/sdk/src/trace/span.h
+++ b/sdk/src/trace/span.h
@@ -1,11 +1,11 @@
 #pragma once
 
+#include "opentelemetry/version.h"
 #include "src/trace/tracer.h"
 
 #include <mutex>
 
-namespace opentelemetry
-{
+OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace trace
@@ -42,4 +42,4 @@ class Span final : public trace_api::Span
 };
 }  // namespace trace
 }  // namespace sdk
-}  // namespace opentelemetry
+OPENTELEMETRY_END_NAMESPACE
diff --git a/sdk/src/trace/tracer.cc b/sdk/src/trace/tracer.cc
index 824c560cfe..4a4c484bc9 100644
--- a/sdk/src/trace/tracer.cc
+++ b/sdk/src/trace/tracer.cc
@@ -1,9 +1,9 @@
 #include "src/trace/tracer.h"
 
+#include "opentelemetry/version.h"
 #include "src/trace/span.h"
 
-namespace opentelemetry
-{
+OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace trace
@@ -17,4 +17,4 @@ nostd::unique_ptr<trace_api::Span> Tracer::StartSpan(
 }
 }  // namespace trace
 }  // namespace sdk
-}  // namespace opentelemetry
+OPENTELEMETRY_END_NAMESPACE
diff --git a/sdk/src/trace/tracer.h b/sdk/src/trace/tracer.h
index 2540c35647..feaf32f479 100644
--- a/sdk/src/trace/tracer.h
+++ b/sdk/src/trace/tracer.h
@@ -1,12 +1,12 @@
 #pragma once
 
 #include "opentelemetry/trace/tracer.h"
+#include "opentelemetry/version.h"
 #include "src/trace/recorder.h"
 
 #include <memory>
 
-namespace opentelemetry
-{
+OPENTELEMETRY_BEGIN_NAMESPACE
 namespace sdk
 {
 namespace trace
@@ -28,4 +28,4 @@ class Tracer final : public trace_api::Tracer, public std::enable_shared_from_th
 };
 }  // namespace trace
 }  // namespace sdk
-}  // namespace opentelemetry
+OPENTELEMETRY_END_NAMESPACE

From 6118363675298b1fa1ae7d085861402715034406 Mon Sep 17 00:00:00 2001
From: Ryan Burn <ryan.burn@gmail.com>
Date: Thu, 12 Mar 2020 15:55:09 -0700
Subject: [PATCH 16/17] Add thread-compatible note

---
 sdk/src/trace/recordable.h | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/sdk/src/trace/recordable.h b/sdk/src/trace/recordable.h
index 8bca640c91..a7298200a5 100644
--- a/sdk/src/trace/recordable.h
+++ b/sdk/src/trace/recordable.h
@@ -14,6 +14,8 @@ namespace trace_api = opentelemetry::trace;
 
 /**
  * Maintains a representation of a span in a format that can be processed by a recorder.
+ *
+ * This class is thread-compatible.
  */
 class Recordable
 {

From 94b6089e9ac2b4d89c5936b237e19e73cd175afa Mon Sep 17 00:00:00 2001
From: Ryan Burn <ryan.burn@gmail.com>
Date: Thu, 12 Mar 2020 16:29:25 -0700
Subject: [PATCH 17/17] Add commenting

---
 sdk/src/trace/span.h   | 1 +
 sdk/src/trace/tracer.h | 1 +
 2 files changed, 2 insertions(+)

diff --git a/sdk/src/trace/span.h b/sdk/src/trace/span.h
index 6d40019882..f4f924aa33 100644
--- a/sdk/src/trace/span.h
+++ b/sdk/src/trace/span.h
@@ -21,6 +21,7 @@ class Span final : public trace_api::Span
 
   ~Span() override;
 
+  // trace_api::Span
   void AddEvent(nostd::string_view name) noexcept override;
 
   void AddEvent(nostd::string_view name, core::SystemTimestamp timestamp) noexcept override;
diff --git a/sdk/src/trace/tracer.h b/sdk/src/trace/tracer.h
index feaf32f479..c242b3c3a7 100644
--- a/sdk/src/trace/tracer.h
+++ b/sdk/src/trace/tracer.h
@@ -14,6 +14,7 @@ namespace trace
 class Tracer final : public trace_api::Tracer, public std::enable_shared_from_this<Tracer>
 {
 public:
+  // Note: recorder must be non-null
   explicit Tracer(std::unique_ptr<Recorder> &&recorder) noexcept : recorder_{std::move(recorder)} {}
 
   Recorder &recorder() const noexcept { return *recorder_; }