[otelcol] add converters to components command (#12385)

<!--Ex. Fixing a bug - Describe the bug and how this fixes the issue.
Ex. Adding a feature - Explain what this achieves.-->
#### Description
Adds list of Converters to command `components`. Additionally, if this
is accepted, Converters must now implement `Type()` function as part of
interface. Given that there are no public converters in core or contrib
repos, I didn't feel like this would be a controversial change, and it
would be very easy for any private users of this interface to update
their code to support it.
<!-- Issue number if applicable -->
#### Link to tracking issue
Extends #11900

<!--Describe what testing was performed and which tests were added.-->
#### Testing
added test data to tests added in 11900, added test to collector_test.go

<!--Describe the documentation added.-->
#### Documentation
Changelog file
<!--Please delete paragraphs that you did not use before submitting.-->

---------

Co-authored-by: Pablo Baeyens <[email protected]>

.chloggen/jackgopack4-add-converters-component-command.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: otelcol
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Converters are now available in the `components` command. 
+
+# One or more tracking issues or pull requests related to the change
+issues: [11900, 12385]
+
+# (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: [user, api]

cmd/builder/internal/builder/templates/main.go.tmpl

@@ -49,7 +49,12 @@ func main() {
 			{{- range .ConfmapProviders}}
 			{{.Name}}.NewFactory().Create(confmap.ProviderSettings{}).Scheme(): "{{.GoMod}}",
 			{{- end}}
-           },
+    }, ConverterModules: []string{
+		  {{- range .ConfmapConverters}}
+			"{{.GoMod}}",
+			{{- end}}
+		},
+
 	}
 
 	if err := run(set); err != nil {

otelcol/collector.go

@@ -72,6 +72,9 @@ type CollectorSettings struct {
 	// ProviderModules maps provider schemes to their respective go modules.
 	ProviderModules map[string]string
 
+	// ConverterModules maps converter names to their respective go modules.
+	ConverterModules []string
+
 	// LoggingOptions provides a way to change behavior of zap logging.
 	LoggingOptions []zap.Option
 

otelcol/collector_test.go

@@ -595,3 +595,31 @@ func newConfFromFile(tb testing.TB, fileName string) map[string]any {
 
 	return confmap.NewFromStringMap(data).ToStringMap()
 }
+
+func TestProviderAndConverterModules(t *testing.T) {
+	set := CollectorSettings{
+		BuildInfo:              component.NewDefaultBuildInfo(),
+		Factories:              nopFactories,
+		ConfigProviderSettings: newDefaultConfigProviderSettings(t, []string{filepath.Join("testdata", "otelcol-nop.yaml")}),
+		ProviderModules: map[string]string{
+			"nop": "go.opentelemetry.io/collector/confmap/provider/testprovider v1.2.3",
+		},
+		ConverterModules: []string{
+			"go.opentelemetry.io/collector/converter/testconverter v1.2.3",
+		},
+	}
+	col, err := NewCollector(set)
+	require.NoError(t, err)
+	wg := startCollector(context.Background(), t, col)
+	require.NoError(t, err)
+	providerModules := map[string]string{
+		"nop": "go.opentelemetry.io/collector/confmap/provider/testprovider v1.2.3",
+	}
+	converterModules := []string{
+		"go.opentelemetry.io/collector/converter/testconverter v1.2.3",
+	}
+	assert.Equal(t, providerModules, col.set.ProviderModules)
+	assert.Equal(t, converterModules, col.set.ConverterModules)
+	col.Shutdown()
+	wg.Wait()
+}

otelcol/command_components.go

@@ -25,7 +25,7 @@ type componentWithStability struct {
 }
 
 type componentWithoutStability struct {
-	Scheme string
+	Scheme string `yaml:",omitempty"`
 	Module string
 }
 
@@ -37,6 +37,7 @@ type componentsOutput struct {
 	Connectors []componentWithStability
 	Extensions []componentWithStability
 	Providers  []componentWithoutStability
+	Converters []componentWithoutStability `yaml:",omitempty"`
 }
 
 // newComponentsCommand constructs a new components command using the given CollectorSettings.
@@ -123,6 +124,12 @@ func newComponentsCommand(set CollectorSettings) *cobra.Command {
 				})
 			}
 
+			for _, converterModule := range set.ConverterModules {
+				components.Converters = append(components.Converters, componentWithoutStability{
+					Module: converterModule,
+				})
+			}
+
 			yamlData, err := yaml.Marshal(components)
 			if err != nil {
 				return err

otelcol/command_components_test.go

@@ -24,6 +24,9 @@ func TestNewBuildSubCommand(t *testing.T) {
 		ProviderModules: map[string]string{
 			"nop": "go.opentelemetry.io/collector/confmap/provider/testprovider v1.2.3",
 		},
+		ConverterModules: []string{
+			"go.opentelemetry.io/collector/converter/testconverter v1.2.3",
+		},
 	}
 	cmd := NewCommand(set)
 	cmd.SetArgs([]string{"components"})

otelcol/testdata/components-output.yaml

@@ -44,3 +44,5 @@ extensions:
 providers:
     - scheme: nop
       module: go.opentelemetry.io/collector/confmap/provider/testprovider v1.2.3
+converters:
+    - module: go.opentelemetry.io/collector/converter/testconverter v1.2.3