Zipkin exporter (#471)

Author: lalitb

CHANGELOG.md

@@ -15,6 +15,8 @@ Increment the:
 
 ## [Unreleased]
 
+* [EXPORTER] Added Zipkin Exporter. ([#471](https://github.com/open-telemetry/opentelemetry-cpp/pull/471))
+
 ## [0.2.0] 2021-03-02
 
 * [SDK] Added `ForceFlush` to `TracerProvider`. ([#588](https://github.com/open-telemetry/opentelemetry-cpp/pull/588)).

CMakeLists.txt

@@ -74,6 +74,7 @@ if(WITH_STL)
 endif()
 
 option(WITH_OTLP "Whether to include the OpenTelemetry Protocol in the SDK" OFF)
+option(WITH_ZIPKIN "Whether to include the Zipkin exporter in the SDK" OFF)
 
 option(WITH_PROMETHEUS "Whether to include the Prometheus Client in the SDK"
        OFF)

exporters/CMakeLists.txt

@@ -1,3 +1,17 @@
+# Copyright 2021, 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.
+
 if(WITH_OTLP)
   add_subdirectory(otlp)
 endif()
@@ -9,6 +23,10 @@ if(WITH_PROMETHEUS)
   add_subdirectory(prometheus)
 endif()
 
+if(WITH_ZIPKIN)
+  add_subdirectory(zipkin)
+endif()
+
 if(WITH_ELASTICSEARCH)
   add_subdirectory(elasticsearch)
 endif()

exporters/zipkin/CMakeLists.txt

@@ -0,0 +1,31 @@
+# Copyright 2021, 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.
+
+include_directories(include)
+find_package(CURL)
+if(CURL_FOUND)
+  add_definitions(-DWITH_CURL)
+endif()
+add_library(zipkin_trace_exporter src/zipkin_exporter.cc src/recordable.cc)
+if(BUILD_TESTING)
+  add_executable(zipkin_recordable_test test/zipkin_recordable_test.cc)
+
+  target_link_libraries(zipkin_recordable_test ${GTEST_BOTH_LIBRARIES}
+                        ${CMAKE_THREAD_LIBS_INIT} zipkin_trace_exporter)
+
+  gtest_add_tests(
+    TARGET zipkin_recordable_test
+    TEST_PREFIX exporter.
+    TEST_LIST zipkin_recordable_test)
+endif() # BUILD_TESTING

exporters/zipkin/include/opentelemetry/exporters/zipkin/recordable.h

@@ -0,0 +1,70 @@
+/*
+ * Copyright The 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.
+ */
+
+#pragma once
+
+#include "nlohmann/json.hpp"
+#include "opentelemetry/sdk/trace/recordable.h"
+#include "opentelemetry/version.h"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace exporter
+{
+namespace zipkin
+{
+using ZipkinSpan = nlohmann::json;
+
+enum class TransportFormat
+{
+  kJson,
+  kProtobuf
+};
+
+class Recordable final : public sdk::trace::Recordable
+{
+public:
+  const ZipkinSpan &span() const noexcept { return span_; }
+
+  void SetIds(trace::TraceId trace_id,
+              trace::SpanId span_id,
+              trace::SpanId parent_span_id) noexcept override;
+
+  void SetAttribute(nostd::string_view key,
+                    const opentelemetry::common::AttributeValue &value) noexcept override;
+
+  void AddEvent(nostd::string_view name,
+                core::SystemTimestamp timestamp,
+                const common::KeyValueIterable &attributes) noexcept override;
+
+  void AddLink(const opentelemetry::trace::SpanContext &span_context,
+               const common::KeyValueIterable &attributes) noexcept override;
+
+  void SetStatus(trace::StatusCode code, nostd::string_view description) noexcept override;
+
+  void SetName(nostd::string_view name) noexcept override;
+
+  void SetStartTime(opentelemetry::core::SystemTimestamp start_time) noexcept override;
+
+  virtual void SetSpanKind(opentelemetry::trace::SpanKind span_kind) noexcept override;
+
+  void SetDuration(std::chrono::nanoseconds duration) noexcept override;
+
+private:
+  ZipkinSpan span_;
+};
+}  // namespace zipkin
+}  // namespace exporter
+OPENTELEMETRY_END_NAMESPACE

exporters/zipkin/include/opentelemetry/exporters/zipkin/zipkin_exporter.h

@@ -0,0 +1,103 @@
+/*
+ * Copyright The 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.
+ */
+
+#pragma once
+
+#include "opentelemetry/exporters/zipkin/recordable.h"
+#include "opentelemetry/ext/http/client/http_client_factory.h"
+#include "opentelemetry/ext/http/common/url_parser.h"
+#include "opentelemetry/sdk/trace/exporter.h"
+#include "opentelemetry/sdk/trace/span_data.h"
+
+#include "nlohmann/json.hpp"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace exporter
+{
+namespace zipkin
+{
+
+const std::string kZipkinEndpointDefault = "http://localhost:9411/api/v2/spans";
+
+/**
+ * Struct to hold Zipkin  exporter options.
+ */
+struct ZipkinExporterOptions
+{
+  // The endpoint to export to. By default the OpenTelemetry Collector's default endpoint.
+  std::string endpoint     = kZipkinEndpointDefault;
+  TransportFormat format   = TransportFormat::kJson;
+  std::string service_name = "default-service";
+  std::string ipv4;
+  std::string ipv6;
+};
+
+namespace trace_sdk   = opentelemetry::sdk::trace;
+namespace http_client = opentelemetry::ext::http::client;
+
+/**
+ * The Zipkin exporter exports span data in JSON format as expected by Zipkin
+ */
+class ZipkinExporter final : public trace_sdk::SpanExporter
+{
+public:
+  /**
+   * Create a ZipkinExporter using all default options.
+   */
+  ZipkinExporter();
+
+  /**
+   * Create a ZipkinExporter using the given options.
+   */
+  explicit ZipkinExporter(const ZipkinExporterOptions &options);
+
+  /**
+   * Create a span recordable.
+   * @return a newly initialized Recordable object
+   */
+  std::unique_ptr<trace_sdk::Recordable> MakeRecordable() noexcept override;
+
+  /**
+   * Export a batch of span recordables in JSON format.
+   * @param spans a span of unique pointers to span recordables
+   */
+  trace_sdk::ExportResult Export(
+      const nostd::span<std::unique_ptr<trace_sdk::Recordable>> &spans) noexcept override;
+
+  /**
+   * Shut down the exporter.
+   * @param timeout an optional timeout, default to max.
+   */
+  bool Shutdown(
+      std::chrono::microseconds timeout = std::chrono::microseconds::max()) noexcept override
+  {
+    return true;
+  }
+
+private:
+  void InitializeLocalEndpoint();
+
+private:
+  // The configuration options associated with this exporter.
+  bool isShutdown_ = false;
+  ZipkinExporterOptions options_;
+  std::shared_ptr<http_client::HttpClientSync> http_client_;
+  opentelemetry::ext::http::common::UrlParser url_parser_;
+  nlohmann::json local_end_point_;
+};
+}  // namespace zipkin
+}  // namespace exporter
+OPENTELEMETRY_END_NAMESPACE