Add "components" Command

.chloggen/build-info-flag.yaml

@@ -0,0 +1,16 @@
+# 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: build-info flag
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note:  Added build flag to output components in collector distribution in YAML format
+
+# One or more tracking issues or pull requests related to the change
+issues: [#4671]
+
+# (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:

CHANGELOG.md

@@ -64,7 +64,6 @@
 - Add prometheus metric prefix to Collector's own telemetry when using OpenTelemetry for internal telemetry (#6223)
 - `exporter/logging`: Apply consistent rendering of map values (#6244)
 - Add support in the confmap.Resolver to expand embedded config URIs inside configuration. (#6276)
-
 ### 🧰 Bug fixes 🧰
 
 - Fixed bug where `telemetryInitializer` is not cleaned up when `newService` errors (#6239)

service/README.md

@@ -36,6 +36,33 @@ For more technical details about how configuration is resolved you can read the
 
     `./otelcorecol --config=file:examples/local/otel-config.yaml --config="yaml:exporters::logging::loglevel: info"`
 
+
+# How to check components available in a distribution
+
+Use the flag --build-info. Below is an example:
+
+```bash
+   .\otelcol --build-info
+```
+Sample output:
+
+```yaml
+
+version: 0.62.1-dev
+receivers:
+   - otlp
+processors:
+   - memory_limiter
+   - batch
+exporters:
+   - logging
+   - otlp
+   - otlphttp
+extensions:
+   - memory_ballast
+   - zpages
+
+```
 ## How to override config properties?
 
 The `--set` flag allows to set arbitrary config property. The `--set` values are merged into the final configuration
@@ -94,4 +121,5 @@ key:
 
 1. Does not support setting a key that contains a dot `.`.
 2. Does not support setting a key that contains a equal sign `=`.
-3. The configuration key separator inside the value part of the property is "::". For example `--set "name={a::b: c}"` is equivalent with `--set name.a.b=c`.
+3. The configuration key separator inside the value part of the property is "::". For example `--set "name={a::b: c}"` is equivalent with `--set name.a.b=c`.
+

service/command.go

@@ -16,7 +16,6 @@ package service // import "go.opentelemetry.io/collector/service"
 
 import (
 	"errors"
-
 	"github.com/spf13/cobra"
 
 	"go.opentelemetry.io/collector/featuregate"
@@ -33,6 +32,11 @@ func NewCommand(set CollectorSettings) *cobra.Command {
 			if err := featuregate.GetRegistry().Apply(gatesList); err != nil {
 				return err
 			}
+			if BuildFlag {
+				err, _ := getBuildInfo(set)
+				return err
+			}
+
 			if set.ConfigProvider == nil {
 				var err error
 

service/flags.go

@@ -17,25 +17,41 @@ package service // import "go.opentelemetry.io/collector/service"
 import (
 	"errors"
 	"flag"
-	"strings"
-
+	"fmt"
+	"go.opentelemetry.io/collector/config"
 	"go.opentelemetry.io/collector/featuregate"
+	"gopkg.in/yaml.v3"
+	"strings"
 )
 
 const (
-	configFlag = "config"
+	configFlag    = "config"
+	buildInfoFlag = "build-info"
 )
 
 var (
 	// Command-line flag that control the configuration file.
 	gatesList = featuregate.FlagValue{}
+	BuildFlag bool
 )
 
 type configFlagValue struct {
 	values []string
 	sets   []string
 }
 
+type componentsOutput struct {
+	Version string
+
+	Receivers []config.Type
+
+	Processors []config.Type
+
+	Exporters []config.Type
+
+	Extensions []config.Type
+}
+
 func (s *configFlagValue) Set(val string) error {
 	s.values = append(s.values, val)
 	return nil
@@ -70,10 +86,40 @@ func flags() *flag.FlagSet {
 		"feature-gates",
 		"Comma-delimited list of feature gate identifiers. Prefix with '-' to disable the feature. '+' or no prefix will enable the feature.")
 
+	flagSet.BoolVar(&BuildFlag, buildInfoFlag, false,
+		"Displays list of components available in collector distribution in yaml format",
+	)
+
 	return flagSet
 }
 
 func getConfigFlag(flagSet *flag.FlagSet) []string {
 	cfv := flagSet.Lookup(configFlag).Value.(*configFlagValue)
 	return append(cfv.values, cfv.sets...)
 }
+
+func getBuildInfo(set CollectorSettings) (error, []byte) {
+	components := componentsOutput{}
+	for ext, _ := range set.Factories.Extensions {
+		components.Extensions = append(components.Extensions, ext)
+	}
+	for prs, _ := range set.Factories.Processors {
+		components.Processors = append(components.Processors, prs)
+	}
+	for rcv, _ := range set.Factories.Receivers {
+		components.Receivers = append(components.Receivers, rcv)
+	}
+	for exp, _ := range set.Factories.Exporters {
+		components.Exporters = append(components.Exporters, exp)
+	}
+	components.Version = set.BuildInfo.Version
+
+	yamlData, err := yaml.Marshal(components)
+
+	if err != nil {
+		return err, nil
+	}
+
+	fmt.Println(string(yamlData))
+	return nil, yamlData
+}

service/flags_test.go

@@ -15,6 +15,12 @@
 package service
 
 import (
+	"go.opentelemetry.io/collector/component"
+	"go.opentelemetry.io/collector/component/componenttest"
+	"go.opentelemetry.io/collector/config"
+	"go.opentelemetry.io/collector/featuregate"
+	"gopkg.in/yaml.v3"
+	"path/filepath"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -78,3 +84,38 @@ func TestSetFlag(t *testing.T) {
 		})
 	}
 }
+func TestBuildInfoFlag(t *testing.T) {
+	factories, err := componenttest.NopFactories()
+	require.NoError(t, err)
+
+	cfgProvider, err := NewConfigProvider(newDefaultConfigProviderSettings([]string{filepath.Join("testdata", "otelcol-nop.yaml")}))
+	require.NoError(t, err)
+
+	set := CollectorSettings{
+		BuildInfo:      component.NewDefaultBuildInfo(),
+		Factories:      factories,
+		ConfigProvider: cfgProvider,
+		telemetry:      newColTelemetry(featuregate.NewRegistry()),
+	}
+	ExpectedYamlStruct := componentsOutput{
+		Version: "latest",
+
+		Receivers: []config.Type{"nop"},
+
+		Processors: []config.Type{"nop"},
+
+		Exporters: []config.Type{"nop"},
+
+		Extensions: []config.Type{"nop"},
+	}
+	ExpectedOutput, err := yaml.Marshal(ExpectedYamlStruct)
+
+	require.NoError(t, err)
+
+	err, Output := getBuildInfo(set)
+
+	require.NoError(t, err)
+
+	assert.Equal(t, ExpectedOutput, Output)
+
+}