[cmd/mdatagen] Add ability to generate configs for resource attributes

.chloggen/mdatagen-allow-resource-attrs-only.yaml

@@ -0,0 +1,11 @@
+# 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. filelogreceiver)
+component: cmd/mdatagen
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Allow setting resource_attributes without introducing the metrics builder.
+
+# One or more tracking issues related to the change
+issues: [21516]

cmd/mdatagen/main.go

@@ -79,7 +79,7 @@ func run(ymlPath string) error {
 			return err
 		}
 	}
-	if len(md.Metrics) == 0 {
+	if len(md.Metrics) == 0 && len(md.ResourceAttributes) == 0 {
 		return nil
 	}
 
@@ -100,6 +100,10 @@ func run(ymlPath string) error {
 		return err
 	}
 
+	if len(md.Metrics) == 0 {
+		return nil
+	}
+
 	if err = generateFile(filepath.Join(tmplDir, "metrics.go.tmpl"),
 		filepath.Join(codeDir, "generated_metrics.go"), md); err != nil {
 		return err

cmd/mdatagen/main_test.go

@@ -28,55 +28,43 @@ import (
 
 func Test_runContents(t *testing.T) {
 	tests := []struct {
-		name                 string
 		yml                  string
 		wantMetricsGenerated bool
+		wantConfigGenerated  bool
 		wantStatusGenerated  bool
 		wantErr              bool
 	}{
 		{
-			name: "valid metadata",
-			yml: `
-type: metricreceiver
-metrics:
-  metric:
-    enabled: true
-    description: Description.
-    unit: s
-    gauge:
-      value_type: double`,
+			yml:     "invalid.yaml",
+			wantErr: true,
+		},
+		{
+			yml:                  "metrics_and_type.yaml",
 			wantMetricsGenerated: true,
+			wantConfigGenerated:  true,
 		},
 		{
-			name:    "invalid yaml",
-			yml:     "invalid",
-			wantErr: true,
+			yml:                 "resource_attributes_only.yaml",
+			wantConfigGenerated: true,
 		},
 		{
-			name: "no metrics but status present",
-			yml: `
-type: metricreceiver
-status:
-  class: exporter
-  stability:
-    beta: [traces, metrics, logs]
-  distributions: [contrib]
-`,
+			yml:                 "status_only.yaml",
 			wantStatusGenerated: true,
 		},
 	}
 	for _, tt := range tests {
-		t.Run(tt.name, func(t *testing.T) {
+		t.Run(tt.yml, func(t *testing.T) {
 			tmpdir := t.TempDir()
-
+			ymlContent, err := os.ReadFile(filepath.Join("testdata", tt.yml))
+			require.NoError(t, err)
 			metadataFile := filepath.Join(tmpdir, "metadata.yaml")
-			require.NoError(t, os.WriteFile(metadataFile, []byte(tt.yml), 0600))
+			require.NoError(t, os.WriteFile(metadataFile, ymlContent, 0600))
 			require.NoError(t, os.WriteFile(filepath.Join(tmpdir, "README.md"), []byte(`
 <!-- status autogenerated section -->
 foo
 <!-- end autogenerated section -->`), 0600))
 
-			err := run(metadataFile)
+			err = run(metadataFile)
 			if tt.wantErr {
 				require.Error(t, err)
 				return
@@ -85,11 +73,22 @@ foo
 
 			if tt.wantMetricsGenerated {
 				require.FileExists(t, filepath.Join(tmpdir, "internal/metadata/generated_metrics.go"))
+				require.FileExists(t, filepath.Join(tmpdir, "internal/metadata/generated_metrics_test.go"))
 				require.FileExists(t, filepath.Join(tmpdir, "documentation.md"))
 			} else {
 				require.NoFileExists(t, filepath.Join(tmpdir, "internal/metadata/generated_metrics.go"))
+				require.NoFileExists(t, filepath.Join(tmpdir, "internal/metadata/generated_metrics_test.go"))
 				require.NoFileExists(t, filepath.Join(tmpdir, "documentation.md"))
 			}
+
+			if tt.wantConfigGenerated {
+				require.FileExists(t, filepath.Join(tmpdir, "internal/metadata/generated_config.go"))
+				require.FileExists(t, filepath.Join(tmpdir, "internal/metadata/generated_config_test.go"))
+			} else {
+				require.NoFileExists(t, filepath.Join(tmpdir, "internal/metadata/generated_config.go"))
+				require.NoFileExists(t, filepath.Join(tmpdir, "internal/metadata/generated_config_test.go"))
+			}
+
 			if tt.wantStatusGenerated {
 				require.FileExists(t, filepath.Join(tmpdir, "internal/metadata/generated_status.go"))
 				contents, err := os.ReadFile(filepath.Join(tmpdir, "README.md"))

cmd/mdatagen/templates/config.go.tmpl

@@ -2,6 +2,7 @@
 
 package {{ .Package }}
 
+{{ if .Metrics -}}
 import "go.opentelemetry.io/collector/confmap"
 
 // MetricConfig provides common config for a particular metric.
@@ -39,6 +40,7 @@ func DefaultMetricsConfig() MetricsConfig {
 		{{- end }}
 	}
 }
+{{- end }}
 
 {{ if .ResourceAttributes -}}
 // ResourceAttributeConfig provides common config for a particular resource attribute.
@@ -64,6 +66,7 @@ func DefaultResourceAttributesConfig() ResourceAttributesConfig {
 }
 {{- end }}
 
+{{ if .Metrics -}}
 // MetricsBuilderConfig is a configuration for {{ .Type }} metrics builder.
 type MetricsBuilderConfig struct {
     Metrics MetricsConfig `mapstructure:"metrics"`
@@ -80,3 +83,4 @@ func DefaultMetricsBuilderConfig() MetricsBuilderConfig {
 		{{- end }}
 	}
 }
+{{- end }}

cmd/mdatagen/templates/config_test.go.tmpl

@@ -13,6 +13,7 @@ import (
 	"go.opentelemetry.io/collector/confmap/confmaptest"
 )
 
+{{ if .Metrics }}
 func TestMetricsBuilderConfig(t *testing.T) {
 	tests := []struct {
 		name string
@@ -77,3 +78,50 @@ func loadMetricsBuilderConfig(t *testing.T, name string) MetricsBuilderConfig {
 	require.NoError(t, component.UnmarshalConfig(sub, &cfg))
 	return cfg
 }
+
+{{- else }}
+
+func TestResourceAttributesConfig(t *testing.T) {
+	tests := []struct {
+		name string
+		want ResourceAttributesConfig
+	}{
+		{
+			name: "default",
+			want: DefaultResourceAttributesConfig(),
+		},
+		{
+			name: "all_set",
+			want: ResourceAttributesConfig{
+                {{- range $name, $_ := .ResourceAttributes }}
+                {{ $name.Render }}: ResourceAttributeConfig{Enabled: true},
+                {{- end }}
+			},
+		},
+		{
+			name: "none_set",
+			want: ResourceAttributesConfig{
+                {{- range $name, $_ := .ResourceAttributes }}
+                {{ $name.Render }}: ResourceAttributeConfig{Enabled: false},
+                {{- end }}
+            },
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+            cm, err := confmaptest.LoadConf(filepath.Join("testdata", "config.yaml"))
+            require.NoError(t, err)
+            sub, err := cm.Sub(tt.name)
+            require.NoError(t, err)
+            sub, err = sub.Sub("resource_attributes")
+            require.NoError(t, err)
+            cfg := DefaultResourceAttributesConfig()
+            require.NoError(t, component.UnmarshalConfig(sub, &cfg))
+
+			if diff := cmp.Diff(tt.want, cfg, cmpopts.IgnoreUnexported(ResourceAttributeConfig{})); diff != "" {
+				t.Errorf("Config mismatch (-expected +actual):\n%s", diff)
+			}
+		})
+	}
+}
+{{- end }}

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

@@ -1,10 +1,12 @@
 default:
 all_set:
+  {{- if .Metrics }}
   metrics:
     {{- range $name, $_ := .Metrics }}
     {{ $name }}:
       enabled: true
     {{- end }}
+  {{- end }}
   {{- if .ResourceAttributes }}
   resource_attributes:
     {{- range $name, $_ := .ResourceAttributes }}
@@ -13,11 +15,13 @@ all_set:
     {{- end }}
   {{- end }}
 none_set:
+  {{- if .Metrics }}
   metrics:
     {{- range $name, $_ := .Metrics }}
     {{ $name }}:
       enabled: false
     {{- end }}
+  {{- end }}
   {{- if .ResourceAttributes }}
   resource_attributes:
     {{- range $name, $_ := .ResourceAttributes }}

cmd/mdatagen/testdata/invalid.yaml

@@ -0,0 +1 @@
+invalid

cmd/mdatagen/testdata/metrics_and_type.yaml

@@ -0,0 +1,8 @@
+type: metricreceiver
+metrics:
+  metric:
+    enabled: true
+    description: Description.
+    unit: s
+    gauge:
+      value_type: double

cmd/mdatagen/testdata/resource_attributes_only.yaml

@@ -0,0 +1,5 @@
+resource_attributes:
+  res.attr1:
+    description: Resource attribute 1.
+    type: string
+    enabled: true

cmd/mdatagen/testdata/status_only.yaml

@@ -0,0 +1,6 @@
+type: metricreceiver
+status:
+  class: exporter
+  stability:
+    beta: [traces, metrics, logs]
+  distributions: [contrib]

receiver/azuremonitorreceiver/go.mod

@@ -7,6 +7,7 @@ require (
 	github.com/Azure/azure-sdk-for-go/sdk/azidentity v1.2.1
 	github.com/Azure/azure-sdk-for-go/sdk/resourcemanager/monitor/armmonitor v0.8.0
 	github.com/Azure/azure-sdk-for-go/sdk/resourcemanager/resources/armresources v1.0.0
+	github.com/google/go-cmp v0.5.9
 	github.com/open-telemetry/opentelemetry-collector-contrib/internal/coreinternal v0.77.0
 	github.com/open-telemetry/opentelemetry-collector-contrib/pkg/pdatatest v0.77.0
 	github.com/stretchr/testify v1.8.2