add baggage to span tags (#5767)

* add baggage to span tags

* update config option naming

* update test

Author: ida613

packages/dd-trace/src/config.js

@@ -477,6 +477,7 @@ class Config {
     this._setValue(defaults, 'appsec.wafTimeout', 5e3) // µs
     this._setValue(defaults, 'baggageMaxBytes', 8192)
     this._setValue(defaults, 'baggageMaxItems', 64)
+    this._setValue(defaults, 'baggageTagKeys', 'user.id,session.id,account.id')
     this._setValue(defaults, 'ciVisibilityTestSessionName', '')
     this._setValue(defaults, 'clientIpEnabled', false)
     this._setValue(defaults, 'clientIpHeader', null)
@@ -731,6 +732,7 @@ class Config {
       DD_TRACE_AWS_ADD_SPAN_POINTERS,
       DD_TRACE_BAGGAGE_MAX_BYTES,
       DD_TRACE_BAGGAGE_MAX_ITEMS,
+      DD_TRACE_BAGGAGE_TAG_KEYS,
       DD_TRACE_CLIENT_IP_ENABLED,
       DD_TRACE_CLIENT_IP_HEADER,
       DD_TRACE_DYNAMODB_TABLE_PRIMARY_KEYS,
@@ -833,6 +835,7 @@ class Config {
     this._envUnprocessed['appsec.wafTimeout'] = DD_APPSEC_WAF_TIMEOUT
     this._setValue(env, 'baggageMaxBytes', DD_TRACE_BAGGAGE_MAX_BYTES)
     this._setValue(env, 'baggageMaxItems', DD_TRACE_BAGGAGE_MAX_ITEMS)
+    this._setValue(env, 'baggageTagKeys', DD_TRACE_BAGGAGE_TAG_KEYS)
     this._setBoolean(env, 'clientIpEnabled', DD_TRACE_CLIENT_IP_ENABLED)
     this._setString(env, 'clientIpHeader', DD_TRACE_CLIENT_IP_HEADER?.toLowerCase())
     this._setBoolean(env, 'crashtracking.enabled', coalesce(
@@ -1063,6 +1066,7 @@ class Config {
     this._setString(opts, 'clientIpHeader', options.clientIpHeader?.toLowerCase())
     this._setValue(opts, 'baggageMaxBytes', options.baggageMaxBytes)
     this._setValue(opts, 'baggageMaxItems', options.baggageMaxItems)
+    this._setValue(opts, 'baggageTagKeys', options.baggageTagKeys)
     this._setBoolean(opts, 'codeOriginForSpans.enabled', options.codeOriginForSpans?.enabled)
     this._setBoolean(
       opts,

packages/dd-trace/src/opentracing/propagation/text_map.js

@@ -633,6 +633,9 @@ class TextMapPropagator {
     if (!carrier || !carrier.baggage) return
     if (!spanContext) removeAllBaggageItems()
     const baggages = carrier.baggage.split(',')
+    const keysToSpanTag = this._config.baggageTagKeys !== '*'
+      ? new Set(this._config.baggageTagKeys.split(','))
+      : undefined
     for (const keyValue of baggages) {
       if (!keyValue.includes('=')) {
         if (spanContext) spanContext._baggageItems = {}
@@ -647,8 +650,11 @@ class TextMapPropagator {
       }
       // the current code assumes precedence of ot-baggage- (legacy opentracing baggage) over baggage
       if (spanContext) {
-        if (key in spanContext._baggageItems) return
+        if (Object.hasOwn(spanContext._baggageItems, key)) continue
         spanContext._baggageItems[key] = value
+        if (this._config.baggageTagKeys === '*' || keysToSpanTag.has(key)) {
+          spanContext._trace.tags['baggage.' + key] = value
+        }
       } else {
         setBaggageItem(key, value)
       }

packages/dd-trace/test/opentracing/propagation/text_map.spec.js

@@ -468,6 +468,72 @@ describe('TextMapPropagator', () => {
       expect(spanContextD._baggageItems).to.deep.equal({})
     })
 
+    it('should add baggage items to span tags', () => {
+      // should add baggage with default keys
+      let carrier = {
+        'x-datadog-trace-id': '123',
+        'x-datadog-parent-id': '456',
+        baggage: 'user.id=capybara,session.id=987,account.id=789,nonDefaultKey=shouldBeIgnored'
+      }
+      const spanContextA = propagator.extract(carrier)
+      expect(spanContextA._trace.tags).to.deep.equal({
+        'baggage.user.id': 'capybara',
+        'baggage.session.id': '987',
+        'baggage.account.id': '789'
+      })
+
+      // should add baggage with case sensitive keys
+      carrier = {
+        'x-datadog-trace-id': '123',
+        'x-datadog-parent-id': '456',
+        baggage: 'user.id=capybara,sesSion.id=987,account.id=789'
+      }
+      const spanContextB = propagator.extract(carrier)
+      expect(spanContextB._trace.tags).to.deep.equal({
+        'baggage.user.id': 'capybara',
+        'baggage.account.id': '789'
+      })
+
+      // should not add baggage when key list is empty
+      config = new Config({
+        baggageTagKeys: ''
+      })
+      propagator = new TextMapPropagator(config)
+      const spanContextC = propagator.extract(carrier)
+      expect(spanContextC._trace.tags).to.deep.equal({})
+
+      // should not add baggage when key list is empty
+      config = new Config({
+        baggageTagKeys: 'customKey'
+      })
+      propagator = new TextMapPropagator(config)
+      carrier = {
+        'x-datadog-trace-id': '123',
+        'x-datadog-parent-id': '456',
+        baggage: 'customKey=beluga,randomKey=shouldBeIgnored'
+      }
+      const spanContextD = propagator.extract(carrier)
+      expect(spanContextD._trace.tags).to.deep.equal({
+        'baggage.customKey': 'beluga'
+      })
+
+      // should add all baggage to span tags
+      config = new Config({
+        baggageTagKeys: '*'
+      })
+      propagator = new TextMapPropagator(config)
+      carrier = {
+        'x-datadog-trace-id': '123',
+        'x-datadog-parent-id': '456',
+        baggage: 'customKey=beluga,randomKey=nothingIsIgnored'
+      }
+      const spanContextE = propagator.extract(carrier)
+      expect(spanContextE._trace.tags).to.deep.equal({
+        'baggage.customKey': 'beluga',
+        'baggage.randomKey': 'nothingIsIgnored'
+      })
+    })
+
     it('should discard malformed tids', () => {
       // tid with malformed characters
       let carrier = {