Add Ostream log exporter and tests

exporters/ostream/BUILD

@@ -1,5 +1,29 @@
 package(default_visibility = ["//visibility:public"])
 
+cc_library(
+    name = "ostream_log_exporter",
+    srcs = [
+        "src/log_exporter.cc",
+    ],
+    hdrs = [
+        "include/opentelemetry/exporters/ostream/log_exporter.h",
+    ],
+    strip_include_prefix = "include",
+    deps = [
+        "//sdk/src/logs",
+        "//sdk/src/trace",
+    ],
+)
+
+cc_test(
+    name = "ostream_log_test",
+    srcs = ["test/ostream_log_test.cc"],
+    deps = [
+        ":ostream_log_exporter",
+        "@com_google_googletest//:gtest_main",
+    ],
+)
+
 cc_library(
     name = "ostream_metrics_exporter",
     srcs = [

exporters/ostream/CMakeLists.txt

@@ -1,11 +1,13 @@
 include_directories(include)
 
+add_library(opentelemetry_exporter_ostream_logs src/log_exporter.cc)
 add_library(opentelemetry_exporter_ostream_metrics src/metrics_exporter.cc)
 add_library(opentelemetry_exporter_ostream_span src/span_exporter.cc)
 
 if(BUILD_TESTING)
   add_executable(ostream_metrics_test test/ostream_metrics_test.cc)
   add_executable(ostream_span_test test/ostream_span_test.cc)
+  add_executable(ostream_log_test test/ostream_log_test.cc)
 
   target_link_libraries(
     ostream_span_test ${GTEST_BOTH_LIBRARIES} ${CMAKE_THREAD_LIBS_INIT}
@@ -15,12 +17,14 @@ if(BUILD_TESTING)
     ostream_metrics_test ${GTEST_BOTH_LIBRARIES} ${CMAKE_THREAD_LIBS_INIT}
     opentelemetry_exporter_ostream_metrics)
 
-  gtest_add_tests(
-    TARGET ostream_metrics_test
-    TEST_PREFIX exporter.
-    TEST_LIST ostream_metrics_test)
-  gtest_add_tests(
-    TARGET ostream_span_test
-    TEST_PREFIX exporter.
-    TEST_LIST ostream_span_test)
+   target_link_libraries(
+    ostream_log_test ${GTEST_BOTH_LIBRARIES} ${CMAKE_THREAD_LIBS_INIT}
+    opentelemetry_exporter_ostream_logs opentelemetry_logs)
+
+  gtest_add_tests(TARGET ostream_log_test TEST_PREFIX exporter. TEST_LIST
+                  ostream_log_test)
+  gtest_add_tests(TARGET ostream_metrics_test TEST_PREFIX exporter. TEST_LIST
+                  ostream_metrics_test)
+  gtest_add_tests(TARGET ostream_span_test TEST_PREFIX exporter. TEST_LIST
+                  ostream_span_test)
 endif() # BUILD_TESTING

exporters/ostream/include/opentelemetry/exporters/ostream/log_exporter.h

@@ -0,0 +1,45 @@
+#pragma once
+
+// #include "nlohmann/json.hpp"
+#include "opentelemetry/logs/log_record.h"
+#include "opentelemetry/nostd/type_traits.h"
+#include "opentelemetry/sdk/logs/exporter.h"
+#include "opentelemetry/version.h"  // needed?
+
+#include <iostream>
+#include <map>
+#include <sstream>
+
+namespace nostd   = opentelemetry::nostd;
+namespace sdklogs = opentelemetry::sdk::logs;
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace exporter
+{
+namespace logs
+{
+/**
+ * The OStreamLogExporter exports logs through an ostream (default set to std::cout)
+ */
+class OStreamLogExporter final : public sdklogs::LogExporter
+{
+public:
+  /**
+   * Create an OStreamLogExporter. This constructor takes in a reference to an ostream that the
+   * export() function will send log data into.
+   * The default ostream is set to stdout
+   */
+  explicit OStreamLogExporter(std::ostream &sout = std::cout) noexcept;
+  sdklogs::ExportResult Export(const nostd::span<std::shared_ptr<opentelemetry::logs::LogRecord>> &
+                                   records) noexcept override;
+
+  bool Shutdown(std::chrono::microseconds timeout = std::chrono::microseconds::max()) noexcept override;
+
+private:
+  std::ostream &sout_;
+  bool isShutdown_ = false;
+  bool firstLog    = true;
+};
+}  // namespace logs
+}  // namespace exporter
+OPENTELEMETRY_END_NAMESPACE

exporters/ostream/src/log_exporter.cc

@@ -0,0 +1,62 @@
+#include "opentelemetry/exporters/ostream/log_exporter.h"
+
+#include <iostream>
+
+namespace nostd   = opentelemetry::nostd;
+namespace sdklogs = opentelemetry::sdk::logs;
+
+OPENTELEMETRY_BEGIN_NAMESPACE
+namespace exporter
+{
+namespace logs
+{
+OStreamLogExporter::OStreamLogExporter(std::ostream &sout) noexcept : sout_(sout) {}
+
+sdklogs::ExportResult OStreamLogExporter::Export(
+    const nostd::span<std::shared_ptr<opentelemetry::logs::LogRecord>> & records) noexcept
+{
+  if (isShutdown_)
+  {
+    return sdklogs::ExportResult::kFailure;
+  }
+
+  for (auto &record : records)
+  {
+    // Convert trace, spanid, traceflags into string convertable representation
+    char trace_id[32] = {0};
+    record->trace_id.ToLowerBase16(trace_id);
+
+    char span_id[16] = {0};
+    record->span_id.ToLowerBase16(span_id);
+
+    char trace_flags[2] = {0};
+    record->trace_flags.ToLowerBase16(trace_flags);
+
+    // Print out each field of the log record
+
+    sout_ << "{\n"
+          << "    timestamp   : " << record->timestamp.time_since_epoch().count() << "\n"
+          << "    severity    : " << static_cast<int>(record->severity) << "\n"
+          << "    name        : " << record->name << "\n"
+          << "    body        : " << record->body
+          << "\n"
+          //       << "    resource     : " <<   record->resource << "\n"
+          //       << "    attributes     : " <<   record->attributes << "\n"
+          << "    trace_id    : " << std::string(trace_id, 32) << "\n"
+          << "    span_id     : " << std::string(span_id, 16) << "\n"
+          << "    trace_flags : " << std::string(trace_flags, 2) << "\n"
+          << "}\n";
+  }
+
+  return sdklogs::ExportResult::kSuccess;
+}
+
+bool OStreamLogExporter::Shutdown(std::chrono::microseconds timeout) noexcept
+{
+  isShutdown_ = true;
+  return true;
+}
+
+}  // namespace logs
+}  // namespace exporter
+OPENTELEMETRY_END_NAMESPACE