[cmd/mdatagen] Don't expose empty resource_attributes config section

If no resource_attributes defined in the metadata.yaml file, don't expose the corresponding empty config section

.chloggen/mdatagen-dont-expose-empty-resource-attributes.yaml

@@ -0,0 +1,11 @@
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: breaking
+
+# The name of the component, or a single word describing the area of concern, (e.g. filelogreceiver)
+component: cmd/mdatagen
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Don't expose `resource_attributes` user config section if it's empty.
+
+# One or more tracking issues related to the change
+issues: [21519]

cmd/mdatagen/templates/metrics.go.tmpl

@@ -187,7 +187,9 @@ func newMetric{{ $name.Render }}(settings MetricSettings) metric{{ $name.Render
 // MetricsBuilderConfig is a structural subset of an otherwise 1-1 copy of metadata.yaml
 type MetricsBuilderConfig struct {
     Metrics MetricsSettings `mapstructure:"metrics"`
+    {{- if .ResourceAttributes }}
     ResourceAttributes ResourceAttributesSettings `mapstructure:"resource_attributes"`
+    {{- end }}
 }
 
 // MetricsBuilder provides an interface for scrapers to report metrics while taking care of all the transformations
@@ -217,7 +219,9 @@ func WithStartTime(startTime pcommon.Timestamp) metricBuilderOption {
 func DefaultMetricsBuilderConfig() MetricsBuilderConfig {
    return MetricsBuilderConfig {
         Metrics: DefaultMetricsSettings(),
+        {{- if .ResourceAttributes }}
         ResourceAttributes: DefaultResourceAttributesSettings(),
+        {{- end }}
    }
 }
 
@@ -243,7 +247,9 @@ func NewMetricsBuilder(mbc MetricsBuilderConfig, settings receiver.CreateSetting
 		startTime:                pcommon.NewTimestampFromTime(time.Now()),
 		metricsBuffer:            pmetric.NewMetrics(),
 		buildInfo:                settings.BuildInfo,
+		{{- if .ResourceAttributes }}
 		resourceAttributesSettings: mbc.ResourceAttributes,
+		{{- end }}
 		{{- range $name, $metric := .Metrics }}
 		metric{{ $name.Render }}: newMetric{{ $name.Render }}(mbc.Metrics.{{ $name.Render }}),
 		{{- end }}

cmd/mdatagen/templates/testdata/config.yaml.tmpl

@@ -5,19 +5,23 @@ all_set:
     {{ $name }}:
       enabled: true
     {{- end }}
+  {{- if .ResourceAttributes }}
   resource_attributes:
     {{- range $name, $_ := .ResourceAttributes }}
     {{ $name }}:
       enabled: true
     {{- end }}
+  {{- end }}
 none_set:
   metrics:
     {{- range $name, $_ := .Metrics }}
     {{ $name }}:
       enabled: false
     {{- end }}
+  {{- if .ResourceAttributes }}
   resource_attributes:
     {{- range $name, $_ := .ResourceAttributes }}
     {{ $name }}:
       enabled: false
     {{- end }}
+  {{- end }}

receiver/activedirectorydsreceiver/internal/metadata/testdata/config.yaml

@@ -37,7 +37,6 @@ all_set:
       enabled: true
     active_directory.ds.thread.count:
       enabled: true
-  resource_attributes:
 none_set:
   metrics:
     active_directory.ds.bind.rate:
@@ -76,4 +75,3 @@ none_set:
       enabled: false
     active_directory.ds.thread.count:
       enabled: false
-  resource_attributes:

receiver/chronyreceiver/internal/metadata/testdata/config.yaml

@@ -15,7 +15,6 @@ all_set:
       enabled: true
     ntp.time.root_delay:
       enabled: true
-  resource_attributes:
 none_set:
   metrics:
     ntp.frequency.offset:
@@ -32,4 +31,3 @@ none_set:
       enabled: false
     ntp.time.root_delay:
       enabled: false
-  resource_attributes:

receiver/expvarreceiver/internal/metadata/testdata/config.yaml

@@ -53,7 +53,6 @@ all_set:
       enabled: true
     process.runtime.memstats.total_alloc:
       enabled: true
-  resource_attributes:
 none_set:
   metrics:
     process.runtime.memstats.buck_hash_sys:
@@ -108,4 +107,3 @@ none_set:
       enabled: false
     process.runtime.memstats.total_alloc:
       enabled: false
-  resource_attributes:

receiver/hostmetricsreceiver/internal/scraper/cpuscraper/internal/metadata/testdata/config.yaml

@@ -5,11 +5,9 @@ all_set:
       enabled: true
     system.cpu.utilization:
       enabled: true
-  resource_attributes:
 none_set:
   metrics:
     system.cpu.time:
       enabled: false
     system.cpu.utilization:
       enabled: false
-  resource_attributes:

receiver/hostmetricsreceiver/internal/scraper/diskscraper/internal/metadata/testdata/config.yaml

@@ -15,7 +15,6 @@ all_set:
       enabled: true
     system.disk.weighted_io_time:
       enabled: true
-  resource_attributes:
 none_set:
   metrics:
     system.disk.io:
@@ -32,4 +31,3 @@ none_set:
       enabled: false
     system.disk.weighted_io_time:
       enabled: false
-  resource_attributes:

receiver/hostmetricsreceiver/internal/scraper/filesystemscraper/internal/metadata/testdata/config.yaml

@@ -7,7 +7,6 @@ all_set:
       enabled: true
     system.filesystem.utilization:
       enabled: true
-  resource_attributes:
 none_set:
   metrics:
     system.filesystem.inodes.usage:
@@ -16,4 +15,3 @@ none_set:
       enabled: false
     system.filesystem.utilization:
       enabled: false
-  resource_attributes:

receiver/hostmetricsreceiver/internal/scraper/loadscraper/internal/metadata/testdata/config.yaml

@@ -7,7 +7,6 @@ all_set:
       enabled: true
     system.cpu.load_average.5m:
       enabled: true
-  resource_attributes:
 none_set:
   metrics:
     system.cpu.load_average.15m:
@@ -16,4 +15,3 @@ none_set:
       enabled: false
     system.cpu.load_average.5m:
       enabled: false
-  resource_attributes: