[chore][cmd/mdatagen] Autogenerate feature gate code when adding it to metadata.yaml #14437

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Merged

Jan 19, 2026

+68 −1

cmd/mdatagen/go.mod

-Original file line number
+Diff line change
@@ Expand Up / @@ -14,6 +14,7 @@ require ( @@
     	go.opentelemetry.io/collector/connector/connectortest v0.143.0
     	go.opentelemetry.io/collector/consumer v1.49.0
     	go.opentelemetry.io/collector/consumer/consumertest v0.143.0
+    	go.opentelemetry.io/collector/featuregate v1.49.0
     	go.opentelemetry.io/collector/filter v0.143.0
     	go.opentelemetry.io/collector/pdata v1.49.0
     	go.opentelemetry.io/collector/pdata/xpdata v0.143.0
@@ Expand Down Expand Up / @@ -60,7 +61,6 @@ require ( @@
     	go.opentelemetry.io/collector/connector/xconnector v0.143.0 // indirect
     	go.opentelemetry.io/collector/consumer/consumererror v0.143.0 // indirect
     	go.opentelemetry.io/collector/consumer/xconsumer v0.143.0 // indirect
-    	go.opentelemetry.io/collector/featuregate v1.49.0 // indirect
     	go.opentelemetry.io/collector/internal/componentalias v0.0.0-00010101000000-000000000000 // indirect
     	go.opentelemetry.io/collector/internal/fanoutconsumer v0.143.0 // indirect
     	go.opentelemetry.io/collector/pdata/pprofile v0.143.0 // indirect
@@ Expand Down @@

cmd/mdatagen/internal/command.go

-Original file line number
+Diff line change
@@ Expand Up / @@ -203,6 +203,10 @@ func run(ymlPath string) error { @@
     		toGenerate[filepath.Join(tmplDir, "logs_test.go.tmpl")] = filepath.Join(codeDir, "generated_logs_test.go")
     	}
+    	if len(md.FeatureGates) > 0 { // only generate feature gates if feature gates are present
+    		toGenerate[filepath.Join(tmplDir, "feature_gates.go.tmpl")] = filepath.Join(codeDir, "generated_feature_gates.go")
+    	}
     	// If at least one file to generate, will need the codeDir
     	if len(toGenerate) > 0 {
     		if err = os.MkdirAll(codeDir, 0o700); err != nil {
@@ Expand Down @@

-Original file line number
+Diff line change
@@ Expand Up / @@ -41,6 +41,7 @@ func TestEnsureTemplatesLoaded(t *testing.T) { @@
     			path.Join(rootDir, "telemetrytest_test.go.tmpl"):   {},
     			path.Join(rootDir, "helper.tmpl"):                  {},
     			path.Join(rootDir, "feature_gates.md.tmpl"):        {},
+    			path.Join(rootDir, "feature_gates.go.tmpl"):        {},
     		}
     		count = 0
     	)
@@ Expand Down @@

cmd/mdatagen/internal/loader_test.go

-Original file line number
+Diff line change
@@ Expand Up / @@ -464,6 +464,15 @@ func TestLoadMetadata(t *testing.T) { @@
     				ScopeName:       "go.opentelemetry.io/collector/internal/receiver/samplereceiver",
     				ShortFolderName: "sample",
     				Tests:           Tests{Host: "newMdatagenNopHost()"},
+    				FeatureGates: []FeatureGate{
+    					{
+    						ID:           "receiver.sample.featuregate.example",
+    						Description:  "This is an example feature gate for testing mdatagen code generation.",
+    						Stage:        "alpha",
+    						FromVersion:  "v0.100.0",
+    						ReferenceURL: "https://github.com/open-telemetry/opentelemetry-collector/issues/12345",
+    					},
+    				},
     			},
     		},
     		{
@@ Expand Down @@

-Original file line number
+Diff line change
@@ Expand Up / @@ -256,3 +256,13 @@ Duration of request [Alpha] @@
     | Unit | Metric Type | Value Type | Stability |
     | ---- | ----------- | ---------- | --------- |
     | s | Histogram | Double | Alpha |
+    ## Feature Gates
+    This component has the following feature gates:
+    | Feature Gate | Stage | Description | From Version | To Version | Reference |
+    | ------------ | ----- | ----------- | ------------ | ---------- | --------- |
+    | `receiver.sample.featuregate.example` | alpha | This is an example feature gate for testing mdatagen code generation. | v0.100.0 | N/A | [Link](https://github.com/open-telemetry/opentelemetry-collector/issues/12345) |
+    For more information about feature gates, see the [Feature Gates](https://github.com/open-telemetry/opentelemetry-collector/blob/main/featuregate/README.md) documentation.

Some generated files are not rendered by default. Learn more about how customized files appear on GitHub.

-Original file line number
+Diff line change
@@ Expand Up / @@ -9,6 +9,13 @@ github_project: open-telemetry/opentelemetry-collector @@
     sem_conv_version: 1.38.0
+    feature_gates:
+      - id: receiver.sample.featuregate.example
+        description: This is an example feature gate for testing mdatagen code generation.
+        stage: alpha
+        from_version: v0.100.0
+        reference_url: https://github.com/open-telemetry/opentelemetry-collector/issues/12345
     status:
       disable_codecov_badge: true
       class: receiver
@@ Expand Down @@

cmd/mdatagen/internal/templates/feature_gates.go.tmpl

-Original file line number
+Diff line change
@@ -0,0 +1,21 @@
+    // Code generated by mdatagen. DO NOT EDIT.
+    package {{ .Package }}
+    import (
+    	"go.opentelemetry.io/collector/featuregate"
+    )
+    {{- range $idx, $gate := .FeatureGates }}
+    var {{ printf "%s" $gate.ID | publicVar }}FeatureGate = featuregate.GlobalRegistry().MustRegister(
+    	"{{ $gate.ID }}",
+    	featuregate.Stage{{ printf "%s" $gate.Stage | casesTitle }},
+    	featuregate.WithRegisterDescription("{{ $gate.Description }}"),
+    	featuregate.WithRegisterReferenceURL("{{ $gate.ReferenceURL }}"),
+    	featuregate.WithRegisterFromVersion("{{ $gate.FromVersion }}"),
+    	{{- if $gate.ToVersion }}
+    	featuregate.WithRegisterToVersion("{{ $gate.ToVersion }}"),
+    	{{- end }}
+    )
+    {{- end }}

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