fix(llmobs): do not submit spans without an ml application specified (#5986)

* fix no ml app error

Author: sabrenner

packages/dd-trace/src/llmobs/tagger.js

@@ -61,19 +61,6 @@ class LLMObsTagger {
     if (!this._config.llmobs.enabled) return
     if (!kind) return // do not register it in the map if it doesn't have an llmobs span kind
 
-    this._register(span)
-
-    if (name) this._setTag(span, NAME, name)
-
-    this._setTag(span, SPAN_KIND, kind)
-    if (modelName) this._setTag(span, MODEL_NAME, modelName)
-    if (modelProvider) this._setTag(span, MODEL_PROVIDER, modelProvider)
-
-    sessionId = sessionId || registry.get(parent)?.[SESSION_ID]
-    if (sessionId) this._setTag(span, SESSION_ID, sessionId)
-    if (integration) this._setTag(span, INTEGRATION, integration)
-    if (_decorator) this._setTag(span, DECORATOR, _decorator)
-
     const spanMlApp =
       mlApp ||
       registry.get(parent)?.[ML_APP] ||
@@ -87,8 +74,21 @@ class LLMObsTagger {
       )
     }
 
+    this._register(span)
+
     this._setTag(span, ML_APP, spanMlApp)
 
+    if (name) this._setTag(span, NAME, name)
+
+    this._setTag(span, SPAN_KIND, kind)
+    if (modelName) this._setTag(span, MODEL_NAME, modelName)
+    if (modelProvider) this._setTag(span, MODEL_PROVIDER, modelProvider)
+
+    sessionId = sessionId || registry.get(parent)?.[SESSION_ID]
+    if (sessionId) this._setTag(span, SESSION_ID, sessionId)
+    if (integration) this._setTag(span, INTEGRATION, integration)
+    if (_decorator) this._setTag(span, DECORATOR, _decorator)
+
     const parentId =
       parent?.context().toSpanId() ??
       span.context()._trace.tags[PROPAGATED_PARENT_ID_KEY] ??

packages/dd-trace/test/llmobs/sdk/integration.spec.js

@@ -294,4 +294,33 @@ describe('end to end sdk integration tests', () => {
       expect(getTag(llmobsSpans[2], 'ml_app')).to.equal('test')
     })
   })
+
+  describe('with no global mlApp', () => {
+    let originalMlApp
+
+    before(() => {
+      originalMlApp = tracer._tracer._config.llmobs.mlApp
+      tracer._tracer._config.llmobs.mlApp = null
+    })
+
+    after(() => {
+      tracer._tracer._config.llmobs.mlApp = originalMlApp
+    })
+
+    it('does not submit a span if there is no mlApp', () => {
+      payloadGenerator = function () {
+        let error
+        try {
+          llmobs.trace({ kind: 'workflow', name: 'myWorkflow' }, () => {})
+        } catch (e) {
+          error = e
+        }
+
+        expect(error).to.exist
+      }
+
+      const { llmobsSpans } = run(payloadGenerator)
+      expect(llmobsSpans).to.have.lengthOf(0)
+    })
+  })
 })