Add a variant of Record() that uses the currently active TagMap. (#225)

Author: g-easy

opencensus/stats/BUILD

@@ -118,6 +118,7 @@ cc_library(
     deps = [
         ":core",
         "//opencensus/tags",
+        "//opencensus/tags:context_util",
         "@com_google_absl//absl/strings",
         "@com_google_absl//absl/time",
     ],
@@ -204,6 +205,7 @@ cc_test(
         ":recording",
         ":test_utils",
         "//opencensus/tags",
+        "//opencensus/tags:with_tag_map",
         "@com_google_googletest//:gtest_main",
     ],
 )

opencensus/stats/internal/recording.cc

@@ -14,14 +14,21 @@
 
 #include "opencensus/stats/recording.h"
 
-#include "absl/time/clock.h"
+#include <initializer_list>
+
 #include "opencensus/stats/internal/delta_producer.h"
 #include "opencensus/stats/measure.h"
+#include "opencensus/tags/context_util.h"
 #include "opencensus/tags/tag_map.h"
 
 namespace opencensus {
 namespace stats {
 
+void Record(std::initializer_list<Measurement> measurements) {
+  DeltaProducer::Get()->Record(measurements,
+                               opencensus::tags::GetCurrentTagMap());
+}
+
 void Record(std::initializer_list<Measurement> measurements,
             opencensus::tags::TagMap tags) {
   DeltaProducer::Get()->Record(measurements, std::move(tags));

opencensus/stats/internal/stats_manager_test.cc

@@ -20,6 +20,8 @@
 #include "opencensus/stats/testing/test_utils.h"
 #include "opencensus/stats/view.h"
 #include "opencensus/tags/tag_key.h"
+#include "opencensus/tags/tag_map.h"
+#include "opencensus/tags/with_tag_map.h"
 
 namespace opencensus {
 namespace stats {
@@ -87,6 +89,33 @@ TEST_F(StatsManagerTest, Count) {
           ::testing::Pair(::testing::ElementsAre("value1", "value2"), 1.0)));
 }
 
+TEST_F(StatsManagerTest, CountTagsFromContext) {
+  ViewDescriptor view_descriptor = ViewDescriptor()
+                                       .set_measure(kFirstMeasureId)
+                                       .set_name("count")
+                                       .set_aggregation(Aggregation::Count())
+                                       .add_column(key1_)
+                                       .add_column(key2_);
+  View view(view_descriptor);
+  ASSERT_EQ(ViewData::Type::kInt64, view.GetData().type());
+  EXPECT_TRUE(view.GetData().int_data().empty());
+
+  opencensus::tags::TagMap tags(
+      {{key1_, "value1"}, {key2_, "value2"}, {key3_, "value3"}});
+  Record({{FirstMeasure(), 2.0}, {FirstMeasure(), 3.0}});
+  {
+    opencensus::tags::WithTagMap wt(tags);
+    Record({{FirstMeasure(), 4.0}});
+  }
+  testing::TestUtils::Flush();
+  const opencensus::stats::ViewData data = view.GetData();
+  EXPECT_THAT(
+      data.int_data(),
+      ::testing::UnorderedElementsAre(
+          ::testing::Pair(::testing::ElementsAre("", ""), 2.0),
+          ::testing::Pair(::testing::ElementsAre("value1", "value2"), 1.0)));
+}
+
 TEST_F(StatsManagerTest, SumDouble) {
   ViewDescriptor view_descriptor = ViewDescriptor()
                                        .set_measure(kFirstMeasureId)

opencensus/stats/recording.h

@@ -23,17 +23,23 @@
 namespace opencensus {
 namespace stats {
 
-// Records a list of Measurements under 'tags'. The recommended style is to
-// create Measurements as an initializer list, e.g.
+// Records a list of Measurements under the current Context's tags. The
+// recommended style is to create Measurements as an initializer list, e.g.:
 //
 //   Record({{measure_double, 2.5}, {measure_int, 1ll}});
 //
 // Only floating point values may be recorded against MeasureDoubles and only
 // integral values against MeasureInt64s, to prevent silent loss of precision.
 // If a record call fails to compile, ensure that all types match (using
 // static_cast to double or int64_t if necessary).
+void Record(std::initializer_list<Measurement> measurements);
+
+// Records a list of Measurements under the specified 'tags'. The current
+// Context's tags are ignored. e.g:
+//
+//   Record({{measure_double, 2.5}}, {{key, "value"}});
 void Record(std::initializer_list<Measurement> measurements,
-            opencensus::tags::TagMap tags = {});
+            opencensus::tags::TagMap tags);
 
 }  // namespace stats
 }  // namespace opencensus