[OTAGENT-206] Add otel collector configs to Agent's config cmd output (#33766)

Author: songy23

pkg/cli/subcommands/config/command.go

@@ -7,13 +7,17 @@
 package config
 
 import (
+	"encoding/json"
 	"fmt"
+	"net/http"
+	"strings"
 
 	"go.uber.org/fx"
 
 	"github.com/DataDog/datadog-agent/comp/core"
 	"github.com/DataDog/datadog-agent/comp/core/config"
 	log "github.com/DataDog/datadog-agent/comp/core/log/def"
+	ddflareextension "github.com/DataDog/datadog-agent/comp/otelcol/ddflareextension/def"
 	"github.com/DataDog/datadog-agent/pkg/api/util"
 	"github.com/DataDog/datadog-agent/pkg/config/settings"
 	"github.com/DataDog/datadog-agent/pkg/util/fxutil"
@@ -117,11 +121,48 @@ func showRuntimeConfiguration(_ log.Component, config config.Component, cliParam
 		return err
 	}
 
+	if config.GetBool("otelcollector.enabled") && config.GetBool("otelcollector.converter.enabled") {
+		runtimeConfig, err = insertOTelCollectorConfig(config.GetString("otelcollector.extension_url"), runtimeConfig, c.HTTPClient())
+		if err != nil {
+			return err
+		}
+	}
+
 	fmt.Println(runtimeConfig)
 
 	return nil
 }
 
+func insertOTelCollectorConfig(extensionURL string, runtimeConfig string, httpClient *http.Client) (string, error) {
+	resp, err := util.DoGet(httpClient, extensionURL, util.CloseConnection)
+	if err != nil {
+		return runtimeConfig, err
+	}
+	var extensionResp ddflareextension.Response
+	if err = json.Unmarshal(resp, &extensionResp); err != nil {
+		return runtimeConfig, err
+	}
+	otelRuntimeCfg := extensionResp.RuntimeConfig
+	var sb strings.Builder
+	for _, cfg := range strings.Split(runtimeConfig, "\n") {
+		sb.WriteString(cfg)
+		sb.WriteString("\n")
+		if cfg == "otelcollector:" {
+			sb.WriteString("  config:")
+			sb.WriteString("\n")
+			for _, otcfg := range strings.Split(otelRuntimeCfg, "\n") {
+				if otcfg == "" {
+					continue
+				}
+				sb.WriteString("    ")
+				sb.WriteString(otcfg)
+				sb.WriteString("\n")
+			}
+		}
+	}
+	return sb.String(), nil
+}
+
 func listRuntimeConfigurableValue(_ log.Component, config config.Component, cliParams *cliParams) error {
 	err := util.SetAuthToken(config)
 	if err != nil {

pkg/config/settings/api.go

@@ -6,6 +6,8 @@
 package settings
 
 import (
+	"net/http"
+
 	"github.com/DataDog/datadog-agent/comp/core/settings"
 	"github.com/spf13/cobra"
 )
@@ -18,6 +20,7 @@ type Client interface {
 	List() (map[string]settings.RuntimeSettingResponse, error)
 	FullConfig() (string, error)
 	FullConfigBySource() (string, error)
+	HTTPClient() *http.Client
 }
 
 // ClientBuilder represents a function returning a runtime settings API client

pkg/config/settings/http/client.go

@@ -142,3 +142,7 @@ func (rc *runtimeSettingsHTTPClient) Set(key string, value string) (bool, error)
 	}
 	return hidden, nil
 }
+
+func (rc *runtimeSettingsHTTPClient) HTTPClient() *http.Client {
+	return rc.c
+}

test/new-e2e/tests/otel/otel-agent/minimal_test.go

@@ -100,3 +100,53 @@ func (s *minimalTestSuite) TestCoreAgentStatus() {
 func (s *minimalTestSuite) TestOTelAgentStatus() {
 	utils.TestOTelAgentStatusCmd(s)
 }
+
+func (s *minimalTestSuite) TestCoreAgentConfigCmd() {
+	const expectedCfg = `    service:
+      extensions:
+      - pprof/dd-autoconfigured
+      - zpages/dd-autoconfigured
+      - health_check/dd-autoconfigured
+      - ddflare/dd-autoconfigured
+      pipelines:
+        logs:
+          exporters:
+          - datadog
+          processors:
+          - batch
+          - infraattributes/dd-autoconfigured
+          receivers:
+          - otlp
+        metrics:
+          exporters:
+          - datadog
+          processors:
+          - batch
+          - infraattributes/dd-autoconfigured
+          receivers:
+          - otlp
+          - datadog/connector
+        metrics/dd-autoconfigured/datadog:
+          exporters:
+          - datadog
+          processors: []
+          receivers:
+          - prometheus/dd-autoconfigured
+        traces:
+          exporters:
+          - datadog/connector
+          processors:
+          - batch
+          - infraattributes/dd-autoconfigured
+          receivers:
+          - otlp
+        traces/send:
+          exporters:
+          - datadog
+          processors:
+          - batch
+          - infraattributes/dd-autoconfigured
+          receivers:
+          - otlp`
+	utils.TestCoreAgentConfigCmd(s, expectedCfg)
+}

test/new-e2e/tests/otel/utils/config_utils.go

@@ -267,3 +267,18 @@ func validateStatus(t *testing.T, status string) {
 	require.Contains(t, status, "Metric Points Sent:")
 	require.Contains(t, status, "Log Records Sent:")
 }
+
+// TestCoreAgentConfigCmd tests the output of core agent's config command contains the embedded collector's config
+func TestCoreAgentConfigCmd(s OTelTestSuite, expectedCfg string) {
+	err := s.Env().FakeIntake.Client().FlushServerAndResetAggregators()
+	require.NoError(s.T(), err)
+	agent := getAgentPod(s)
+
+	s.T().Log("Calling config command in core agent")
+	stdout, stderr, err := s.Env().KubernetesCluster.KubernetesClient.PodExec("datadog", agent.Name, "agent", []string{"agent", "config"})
+	require.NoError(s.T(), err, "Failed to execute config")
+	require.Empty(s.T(), stderr)
+	require.NotNil(s.T(), stdout)
+	s.T().Log("Full output of config command in core agent\n", stdout)
+	assert.Contains(s.T(), stdout, expectedCfg)
+}