From 37a58a4736c21567e2926e4463043701d4d9de58 Mon Sep 17 00:00:00 2001
From: David Ashpole <dashpole@google.com>
Date: Fri, 19 Apr 2024 18:49:28 +0000
Subject: [PATCH] Support metric.metadata in pdata/pmetric

---
 .chloggen/metric-metadata.yaml                | 25 +++++++++++++++++++
 .../cmd/pdatagen/internal/pmetric_package.go  |  4 +++
 pdata/pmetric/generated_metric.go             |  7 ++++++
 pdata/pmetric/generated_metric_test.go        |  9 +++++++
 4 files changed, 45 insertions(+)
 create mode 100644 .chloggen/metric-metadata.yaml

diff --git a/.chloggen/metric-metadata.yaml b/.chloggen/metric-metadata.yaml
new file mode 100644
index 00000000000..623c54562d5
--- /dev/null
+++ b/.chloggen/metric-metadata.yaml
@@ -0,0 +1,25 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: pmetric
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Support metric.metadata in pdata/pmetric
+
+# One or more tracking issues or pull requests related to the change
+issues: []
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: [api]
diff --git a/pdata/internal/cmd/pdatagen/internal/pmetric_package.go b/pdata/internal/cmd/pdatagen/internal/pmetric_package.go
index 95487c00f8f..68aee5219f9 100644
--- a/pdata/internal/cmd/pdatagen/internal/pmetric_package.go
+++ b/pdata/internal/cmd/pdatagen/internal/pmetric_package.go
@@ -115,6 +115,10 @@ var metric = &messageValueStruct{
 			defaultVal: `""`,
 			testVal:    `"1"`,
 		},
+		&sliceField{
+			fieldName:   "Metadata",
+			returnSlice: mapStruct,
+		},
 		&oneOfField{
 			typeName:                   "MetricType",
 			originFieldName:            "Data",
diff --git a/pdata/pmetric/generated_metric.go b/pdata/pmetric/generated_metric.go
index 839628520df..ecf2dba29ef 100644
--- a/pdata/pmetric/generated_metric.go
+++ b/pdata/pmetric/generated_metric.go
@@ -9,6 +9,7 @@ package pmetric
 import (
 	"go.opentelemetry.io/collector/pdata/internal"
 	otlpmetrics "go.opentelemetry.io/collector/pdata/internal/data/protogen/metrics/v1"
+	"go.opentelemetry.io/collector/pdata/pcommon"
 )
 
 // Metric represents one metric as a collection of datapoints.
@@ -79,6 +80,11 @@ func (ms Metric) SetUnit(v string) {
 	ms.orig.Unit = v
 }
 
+// Metadata returns the Metadata associated with this Metric.
+func (ms Metric) Metadata() pcommon.Map {
+	return pcommon.Map(internal.NewMap(&ms.orig.Metadata, ms.state))
+}
+
 // Type returns the type of the data for this Metric.
 // Calling this function on zero-initialized Metric will cause a panic.
 func (ms Metric) Type() MetricType {
@@ -233,6 +239,7 @@ func (ms Metric) CopyTo(dest Metric) {
 	dest.SetName(ms.Name())
 	dest.SetDescription(ms.Description())
 	dest.SetUnit(ms.Unit())
+	ms.Metadata().CopyTo(dest.Metadata())
 	switch ms.Type() {
 	case MetricTypeGauge:
 		ms.Gauge().CopyTo(dest.SetEmptyGauge())
diff --git a/pdata/pmetric/generated_metric_test.go b/pdata/pmetric/generated_metric_test.go
index 920891b6096..e761f14a321 100644
--- a/pdata/pmetric/generated_metric_test.go
+++ b/pdata/pmetric/generated_metric_test.go
@@ -13,6 +13,7 @@ import (
 
 	"go.opentelemetry.io/collector/pdata/internal"
 	otlpmetrics "go.opentelemetry.io/collector/pdata/internal/data/protogen/metrics/v1"
+	"go.opentelemetry.io/collector/pdata/pcommon"
 )
 
 func TestMetric_MoveTo(t *testing.T) {
@@ -65,6 +66,13 @@ func TestMetric_Unit(t *testing.T) {
 	assert.Panics(t, func() { newMetric(&otlpmetrics.Metric{}, &sharedState).SetUnit("1") })
 }
 
+func TestMetric_Metadata(t *testing.T) {
+	ms := NewMetric()
+	assert.Equal(t, pcommon.NewMap(), ms.Metadata())
+	internal.FillTestMap(internal.Map(ms.Metadata()))
+	assert.Equal(t, pcommon.Map(internal.GenerateTestMap()), ms.Metadata())
+}
+
 func TestMetric_Type(t *testing.T) {
 	tv := NewMetric()
 	assert.Equal(t, MetricTypeEmpty, tv.Type())
@@ -175,6 +183,7 @@ func fillTestMetric(tv Metric) {
 	tv.orig.Name = "test_name"
 	tv.orig.Description = "test_description"
 	tv.orig.Unit = "1"
+	internal.FillTestMap(internal.NewMap(&tv.orig.Metadata, tv.state))
 	tv.orig.Data = &otlpmetrics.Metric_Sum{Sum: &otlpmetrics.Sum{}}
 	fillTestSum(newSum(tv.orig.GetSum(), tv.state))
 }