internal/telemetry: add process tags to telemetry payloads (#3586)

Co-authored-by: Kemal Akkoyun <[email protected]>

Author: rarguelloF

internal/telemetry/internal/transport/body.go

@@ -18,6 +18,7 @@ type Application struct {
 	TracerVersion   string `json:"tracer_version"`
 	LanguageName    string `json:"language_name"`
 	LanguageVersion string `json:"language_version"`
+	ProcessTags     string `json:"process_tags,omitempty"`
 }
 
 // Host is identifying information about the host on which the app

internal/telemetry/internal/writer.go

@@ -23,6 +23,7 @@ import (
 	"github.com/DataDog/dd-trace-go/v2/internal/hostname"
 	"github.com/DataDog/dd-trace-go/v2/internal/log"
 	"github.com/DataDog/dd-trace-go/v2/internal/osinfo"
+	"github.com/DataDog/dd-trace-go/v2/internal/processtags"
 	"github.com/DataDog/dd-trace-go/v2/internal/telemetry/internal/transport"
 	"github.com/DataDog/dd-trace-go/v2/internal/version"
 )
@@ -67,6 +68,7 @@ func newBody(config TracerConfig, debugMode bool) *transport.Body {
 			TracerVersion:   version.Tag,
 			LanguageName:    "go",
 			LanguageVersion: runtime.Version(),
+			ProcessTags:     processtags.GlobalTags().String(),
 		},
 		Host: transport.Host{
 			Hostname:      osHostname,

internal/telemetry/internal/writer_test.go

@@ -17,6 +17,7 @@ import (
 	"github.com/stretchr/testify/assert"
 	"github.com/stretchr/testify/require"
 
+	"github.com/DataDog/dd-trace-go/v2/internal/processtags"
 	"github.com/DataDog/dd-trace-go/v2/internal/telemetry/internal/transport"
 )
 
@@ -52,6 +53,40 @@ func TestNewWriter_NoEndpoints(t *testing.T) {
 	assert.Nil(t, writer)
 }
 
+func TestNewWriter_ProcessTags(t *testing.T) {
+	cfg := WriterConfig{
+		TracerConfig: TracerConfig{
+			Service: "test-service",
+			Env:     "test-env",
+			Version: "1.0.0",
+		},
+		Endpoints: []*http.Request{
+			{Method: http.MethodPost, URL: &url.URL{Scheme: "http", Host: "localhost", Path: "/telemetry"}},
+		},
+	}
+
+	t.Run("enabled", func(t *testing.T) {
+		t.Setenv("DD_EXPERIMENTAL_PROPAGATE_PROCESS_TAGS_ENABLED", "true")
+		processtags.Reload()
+
+		w, err := NewWriter(cfg)
+		require.NoError(t, err)
+
+		body := w.(*writer).body
+		assert.NotEmpty(t, body.Application.ProcessTags)
+	})
+	t.Run("disabled", func(t *testing.T) {
+		t.Setenv("DD_EXPERIMENTAL_PROPAGATE_PROCESS_TAGS_ENABLED", "false")
+		processtags.Reload()
+
+		w, err := NewWriter(cfg)
+		require.NoError(t, err)
+
+		body := w.(*writer).body
+		assert.Empty(t, body.Application.ProcessTags)
+	})
+}
+
 type testPayload struct {
 	RequestTypeValue transport.RequestType `json:"request_type"`
 	marshalJSON      func() ([]byte, error)