[mdatagen] move telemetry into its own file (#10037)

This is in preparation for using mdatagen for component telemetry.

---------

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

cmd/mdatagen/embeded_templates_test.go

@@ -31,6 +31,8 @@ func TestEnsureTemplatesLoaded(t *testing.T) {
 			path.Join(rootDir, "package_test.go.tmpl"):         {},
 			path.Join(rootDir, "readme.md.tmpl"):               {},
 			path.Join(rootDir, "status.go.tmpl"):               {},
+			path.Join(rootDir, "telemetry.go.tmpl"):            {},
+			path.Join(rootDir, "telemetry_test.go.tmpl"):       {},
 			path.Join(rootDir, "testdata", "config.yaml.tmpl"): {},
 		}
 		count = 0

cmd/mdatagen/main.go

@@ -62,6 +62,14 @@ func run(ymlPath string) error {
 				filepath.Join(codeDir, "generated_status.go"), md, "metadata"); err != nil {
 				return err
 			}
+			if err = generateFile(filepath.Join(tmplDir, "telemetry.go.tmpl"),
+				filepath.Join(codeDir, "generated_telemetry.go"), md, "metadata"); err != nil {
+				return err
+			}
+			if err = generateFile(filepath.Join(tmplDir, "telemetry_test.go.tmpl"),
+				filepath.Join(codeDir, "generated_telemetry_test.go"), md, "metadata"); err != nil {
+				return err
+			}
 			if err = generateFile(filepath.Join(tmplDir, "component_test.go.tmpl"),
 				filepath.Join(ymlDir, "generated_component_test.go"), md, packageName); err != nil {
 				return err

cmd/mdatagen/main_test.go

@@ -437,8 +437,6 @@ package metadata
 
 import (
 	"go.opentelemetry.io/collector/component"
-	"go.opentelemetry.io/otel/metric"
-	"go.opentelemetry.io/otel/trace"
 )
 
 var (
@@ -448,6 +446,80 @@ var (
 const (
 	MetricsStability = component.StabilityLevelBeta
 )
+`,
+		},
+		{
+			name: "foo component with alpha status",
+			md: metadata{
+				Type: "foo",
+				Status: &Status{
+					Stability: map[component.StabilityLevel][]string{
+						component.StabilityLevelAlpha: {"metrics"},
+					},
+					Distributions: []string{"contrib"},
+					Class:         "receiver",
+				},
+			},
+			expected: `// Code generated by mdatagen. DO NOT EDIT.
+
+package metadata
+
+import (
+	"go.opentelemetry.io/collector/component"
+)
+
+var (
+	Type = component.MustNewType("foo")
+)
+
+const (
+	MetricsStability = component.StabilityLevelAlpha
+)
+`,
+		},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			tmpdir := t.TempDir()
+			err := generateFile("templates/status.go.tmpl",
+				filepath.Join(tmpdir, "generated_status.go"), tt.md, "metadata")
+			require.NoError(t, err)
+			actual, err := os.ReadFile(filepath.Join(tmpdir, "generated_status.go")) // nolint: gosec
+			require.NoError(t, err)
+			require.Equal(t, tt.expected, string(actual))
+		})
+	}
+}
+
+func TestGenerateTelemetryMetadata(t *testing.T) {
+	tests := []struct {
+		name     string
+		output   string
+		md       metadata
+		expected string
+	}{
+		{
+			name: "foo component with beta status",
+			md: metadata{
+				Type: "foo",
+				Status: &Status{
+					Stability: map[component.StabilityLevel][]string{
+						component.StabilityLevelBeta: {"metrics"},
+					},
+					Distributions: []string{"contrib"},
+					Class:         "receiver",
+				},
+			},
+			expected: `// Code generated by mdatagen. DO NOT EDIT.
+
+package metadata
+
+import (
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/trace"
+)
 
 func Meter(settings component.TelemetrySettings) metric.Meter {
 	return settings.MeterProvider.Meter("")
@@ -480,14 +552,6 @@ import (
 	"go.opentelemetry.io/otel/trace"
 )
 
-var (
-	Type = component.MustNewType("foo")
-)
-
-const (
-	MetricsStability = component.StabilityLevelAlpha
-)
-
 func Meter(settings component.TelemetrySettings) metric.Meter {
 	return settings.MeterProvider.Meter("")
 }
@@ -502,10 +566,10 @@ func Tracer(settings component.TelemetrySettings) trace.Tracer {
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {
 			tmpdir := t.TempDir()
-			err := generateFile("templates/status.go.tmpl",
-				filepath.Join(tmpdir, "generated_status.go"), tt.md, "metadata")
+			err := generateFile("templates/telemetry.go.tmpl",
+				filepath.Join(tmpdir, "generated_telemetry.go"), tt.md, "metadata")
 			require.NoError(t, err)
-			actual, err := os.ReadFile(filepath.Join(tmpdir, "generated_status.go")) // nolint: gosec
+			actual, err := os.ReadFile(filepath.Join(tmpdir, "generated_telemetry.go")) // nolint: gosec
 			require.NoError(t, err)
 			require.Equal(t, tt.expected, string(actual))
 		})

cmd/mdatagen/templates/status.go.tmpl

@@ -4,8 +4,6 @@ package {{ .Package }}
 
 import (
 	"go.opentelemetry.io/collector/component"
-	"go.opentelemetry.io/otel/metric"
-	"go.opentelemetry.io/otel/trace"
 )
 
 var (
@@ -19,11 +17,3 @@ const (
 	{{- end }}
 	{{- end }}
 )
-
-func Meter(settings component.TelemetrySettings) metric.Meter {
-	return settings.MeterProvider.Meter("{{ .ScopeName }}")
-}
-
-func Tracer(settings component.TelemetrySettings) trace.Tracer {
-	return settings.TracerProvider.Tracer("{{ .ScopeName }}")
-}

cmd/mdatagen/templates/telemetry.go.tmpl

@@ -0,0 +1,17 @@
+// Code generated by mdatagen. DO NOT EDIT.
+
+package {{ .Package }}
+
+import (
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/otel/metric"
+	"go.opentelemetry.io/otel/trace"
+)
+
+func Meter(settings component.TelemetrySettings) metric.Meter {
+	return settings.MeterProvider.Meter("{{ .ScopeName }}")
+}
+
+func Tracer(settings component.TelemetrySettings) trace.Tracer {
+	return settings.TracerProvider.Tracer("{{ .ScopeName }}")
+}

cmd/mdatagen/templates/telemetry_test.go.tmpl

@@ -0,0 +1,63 @@
+// Code generated by mdatagen. DO NOT EDIT.
+
+package {{ .Package }}
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/require"
+	"go.opentelemetry.io/otel/metric"
+	embeddedmetric "go.opentelemetry.io/otel/metric/embedded"
+	noopmetric "go.opentelemetry.io/otel/metric/noop"
+	"go.opentelemetry.io/otel/trace"
+	embeddedtrace "go.opentelemetry.io/otel/trace/embedded"
+	nooptrace "go.opentelemetry.io/otel/trace/noop"
+
+	"go.opentelemetry.io/collector/component"
+)
+
+type mockMeter struct {
+	noopmetric.Meter
+	name string
+}
+type mockMeterProvider struct {
+	embeddedmetric.MeterProvider
+}
+
+func (m mockMeterProvider) Meter(name string, opts ...metric.MeterOption) metric.Meter {
+	return mockMeter{name: name}
+}
+
+type mockTracer struct {
+	nooptrace.Tracer
+	name string
+}
+
+type mockTracerProvider struct {
+	embeddedtrace.TracerProvider
+}
+
+func (m mockTracerProvider) Tracer(name string, opts ...trace.TracerOption) trace.Tracer {
+	return mockTracer{name: name}
+}
+
+func TestProviders(t *testing.T) {
+	set := component.TelemetrySettings{
+		MeterProvider: mockMeterProvider{},
+		TracerProvider: mockTracerProvider{},
+	}
+
+	meter := Meter(set)
+	if m, ok := meter.(mockMeter); ok {
+		require.Equal(t, "{{ .ScopeName }}", m.name)
+	} else {
+		require.Fail(t, "returned Meter not mockMeter")
+	}
+
+	tracer := Tracer(set)
+	if m, ok := tracer.(mockTracer); ok {
+		require.Equal(t, "{{ .ScopeName }}", m.name)
+	} else {
+		require.Fail(t, "returned Meter not mockTracer")
+	}
+}