[mdatagen] mdatagen support validate metrics in in telemetry section (#…

…10942)

#### Description

I have a use case, I define an attribute and try to use it in
`telemetry.metric` however I encounter an error: `unused attributes:
[xxx]`
So, I push this PR to enhance the `validateMetrics()` func to support
validate metrics in `telemetry.metric`

#### Link to tracking issue fix
Fixes #10925

---------

Co-authored-by: Alex Boten <223565+codeboten@users.noreply.github.com>

.chloggen/fix-metadatagen-validate.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: mdatagen
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: mdatagen `validateMetrics()` support validate metrics in `telemetry.metric`
+
+# One or more tracking issues or pull requests related to the change
+issues: [10925]
+
+# (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: []

cmd/mdatagen/testdata/unused_attribute.yaml

@@ -10,7 +10,10 @@ status:
     stable: [metrics]
 
 attributes:
-  used_attr:
+  used_attr_in_metrics_section:
+    description: Used attribute.
+    type: string
+  used_attr_in_telemetry_section:
     description: Used attribute.
     type: string
 
@@ -26,4 +29,14 @@ metrics:
     unit: "1"
     gauge:
       value_type: double
-    attributes: [used_attr]
+    attributes: [used_attr_in_metrics_section]
+
+telemetry:
+  metrics:
+    metric:
+      enabled: true
+      description: Metric.
+      unit: "1"
+      gauge:
+        value_type: double
+      attributes: [used_attr_in_telemetry_section]

cmd/mdatagen/validate.go

@@ -129,34 +129,9 @@ func (md *metadata) validateResourceAttributes() error {
 func (md *metadata) validateMetrics() error {
 	var errs error
 	usedAttrs := map[attributeName]bool{}
-	for mn, m := range md.Metrics {
-		if m.Sum == nil && m.Gauge == nil {
-			errs = errors.Join(errs, fmt.Errorf("metric %v doesn't have a metric type key, "+
-				"one of the following has to be specified: sum, gauge", mn))
-			continue
-		}
-		if m.Sum != nil && m.Gauge != nil {
-			errs = errors.Join(errs, fmt.Errorf("metric %v has more than one metric type keys, "+
-				"only one of the following has to be specified: sum, gauge", mn))
-			continue
-		}
-		if err := m.validate(); err != nil {
-			errs = errors.Join(errs, fmt.Errorf(`metric "%v": %w`, mn, err))
-			continue
-		}
-		unknownAttrs := make([]attributeName, 0, len(m.Attributes))
-		for _, attr := range m.Attributes {
-			if _, ok := md.Attributes[attr]; ok {
-				usedAttrs[attr] = true
-			} else {
-				unknownAttrs = append(unknownAttrs, attr)
-			}
-		}
-		if len(unknownAttrs) > 0 {
-			errs = errors.Join(errs, fmt.Errorf(`metric "%v" refers to undefined attributes: %v`, mn, unknownAttrs))
-		}
-	}
-	errs = errors.Join(errs, md.validateAttributes(usedAttrs))
+	errs = errors.Join(errs, validateMetrics(md.Metrics, md.Attributes, usedAttrs),
+		validateMetrics(md.Telemetry.Metrics, md.Attributes, usedAttrs),
+		md.validateAttributes(usedAttrs))
 	return errs
 }
 
@@ -204,3 +179,35 @@ func (md *metadata) validateAttributes(usedAttrs map[attributeName]bool) error {
 	}
 	return errs
 }
+
+func validateMetrics(metrics map[metricName]metric, attributes map[attributeName]attribute, usedAttrs map[attributeName]bool) error {
+	var errs error
+	for mn, m := range metrics {
+		if m.Sum == nil && m.Gauge == nil && m.Histogram == nil {
+			errs = errors.Join(errs, fmt.Errorf("metric %v doesn't have a metric type key, "+
+				"one of the following has to be specified: sum, gauge, histogram", mn))
+			continue
+		}
+		if (m.Sum != nil && m.Gauge != nil) || (m.Sum != nil && m.Histogram != nil) || (m.Gauge != nil && m.Histogram != nil) {
+			errs = errors.Join(errs, fmt.Errorf("metric %v has more than one metric type keys, "+
+				"only one of the following has to be specified: sum, gauge, histogram", mn))
+			continue
+		}
+		if err := m.validate(); err != nil {
+			errs = errors.Join(errs, fmt.Errorf(`metric "%v": %w`, mn, err))
+			continue
+		}
+		unknownAttrs := make([]attributeName, 0, len(m.Attributes))
+		for _, attr := range m.Attributes {
+			if _, ok := attributes[attr]; ok {
+				usedAttrs[attr] = true
+			} else {
+				unknownAttrs = append(unknownAttrs, attr)
+			}
+		}
+		if len(unknownAttrs) > 0 {
+			errs = errors.Join(errs, fmt.Errorf(`metric "%v" refers to undefined attributes: %v`, mn, unknownAttrs))
+		}
+	}
+	return errs
+}

cmd/mdatagen/validate_test.go

@@ -69,12 +69,12 @@ func TestValidate(t *testing.T) {
 		{
 			name: "testdata/no_metric_type.yaml",
 			wantErr: "metric system.cpu.time doesn't have a metric type key, " +
-				"one of the following has to be specified: sum, gauge",
+				"one of the following has to be specified: sum, gauge, histogram",
 		},
 		{
 			name: "testdata/two_metric_types.yaml",
 			wantErr: "metric system.cpu.time has more than one metric type keys, " +
-				"only one of the following has to be specified: sum, gauge",
+				"only one of the following has to be specified: sum, gauge, histogram",
 		},
 		{
 			name:    "testdata/invalid_input_type.yaml",