[CONFIGURATION] File configuration - zipkin exporter builder (open-telemetry#3565)

Author: marcalff

exporters/zipkin/include/opentelemetry/exporters/zipkin/zipkin_builder.h

@@ -0,0 +1,33 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#pragma once
+
+#include <memory>
+
+#include "opentelemetry/sdk/configuration/registry.h"
+#include "opentelemetry/sdk/configuration/zipkin_span_exporter_builder.h"
+#include "opentelemetry/sdk/configuration/zipkin_span_exporter_configuration.h"
+#include "opentelemetry/sdk/trace/exporter.h"
+#include "opentelemetry/version.h"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace exporter
+{
+namespace zipkin
+{
+
+class OPENTELEMETRY_EXPORT ZipkinBuilder
+    : public opentelemetry::sdk::configuration::ZipkinSpanExporterBuilder
+{
+public:
+  static void Register(opentelemetry::sdk::configuration::Registry *registry);
+
+  std::unique_ptr<opentelemetry::sdk::trace::SpanExporter> Build(
+      const opentelemetry::sdk::configuration::ZipkinSpanExporterConfiguration *model)
+      const override;
+};
+
+}  // namespace zipkin
+}  // namespace exporter
+OPENTELEMETRY_END_NAMESPACE

exporters/zipkin/include/opentelemetry/exporters/zipkin/zipkin_exporter_options.h

@@ -13,6 +13,7 @@ namespace exporter
 namespace zipkin
 {
 
+// The endpoint to export to. By default the OpenTelemetry Collector's default endpoint.
 inline const std::string GetDefaultZipkinEndpoint()
 {
   const char *otel_exporter_zipkin_endpoint_env = "OTEL_EXPORTER_ZIPKIN_ENDPOINT";
@@ -36,8 +37,13 @@ enum class TransportFormat
  */
 struct ZipkinExporterOptions
 {
-  // The endpoint to export to. By default the OpenTelemetry Collector's default endpoint.
-  std::string endpoint     = GetDefaultZipkinEndpoint();
+  // Lookup environment variables
+  ZipkinExporterOptions() : endpoint(GetDefaultZipkinEndpoint()) {}
+
+  // No defaults
+  ZipkinExporterOptions(void *) : endpoint("") {}
+
+  std::string endpoint;
   TransportFormat format   = TransportFormat::kJson;
   std::string service_name = "default-service";
   std::string ipv4;

exporters/zipkin/src/zipkin_builder.cc

@@ -0,0 +1,41 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+#include <memory>
+#include <string>
+#include <utility>
+
+#include "opentelemetry/exporters/zipkin/zipkin_builder.h"
+#include "opentelemetry/exporters/zipkin/zipkin_exporter_factory.h"
+#include "opentelemetry/exporters/zipkin/zipkin_exporter_options.h"
+#include "opentelemetry/sdk/configuration/registry.h"
+#include "opentelemetry/sdk/configuration/zipkin_span_exporter_builder.h"
+#include "opentelemetry/sdk/configuration/zipkin_span_exporter_configuration.h"
+#include "opentelemetry/sdk/trace/exporter.h"
+#include "opentelemetry/version.h"
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace exporter
+{
+namespace zipkin
+{
+
+void ZipkinBuilder::Register(opentelemetry::sdk::configuration::Registry *registry)
+{
+  auto builder = std::make_unique<ZipkinBuilder>();
+  registry->SetZipkinSpanBuilder(std::move(builder));
+}
+
+std::unique_ptr<opentelemetry::sdk::trace::SpanExporter> ZipkinBuilder::Build(
+    const opentelemetry::sdk::configuration::ZipkinSpanExporterConfiguration *model) const
+{
+  ZipkinExporterOptions options(nullptr);
+
+  options.endpoint = model->endpoint;
+
+  return ZipkinExporterFactory::Create(options);
+}
+
+}  // namespace zipkin
+}  // namespace exporter
+OPENTELEMETRY_END_NAMESPACE