Add integration test, update example

integrations/langfuse/example/chat.py

@@ -31,3 +31,4 @@
         data={"prompt_builder": {"template_variables": {"location": "Berlin"}, "prompt_source": messages}}
     )
     print(response["llm"]["replies"][0])
+    print(response["tracer"]["trace_url"])

integrations/langfuse/tests/test_tracing.py

@@ -0,0 +1,54 @@
+import os
+from urllib.parse import urlparse
+
+import pytest
+import requests
+
+from haystack import Pipeline
+from haystack.components.builders import DynamicChatPromptBuilder
+from haystack.components.generators.chat import OpenAIChatGenerator
+from haystack.dataclasses import ChatMessage
+from requests.auth import HTTPBasicAuth
+
+from haystack_integrations.components.others.langfuse import LangfuseComponent
+
+
+@pytest.mark.integration
+@pytest.mark.skipif(
+        not os.environ.get("LANGFUSE_SECRET_KEY", None) and not os.environ.get("LANGFUSE_PUBLIC_KEY", None),
+        reason="Export an env var called LANGFUSE_SECRET_KEY and LANGFUSE_PUBLIC_KEY containing Langfuse credentials.",
+    )
+def test_tracing_integration():
+
+    pipe = Pipeline()
+    pipe.add_component("tracer", LangfuseComponent("Chat example"))
+    pipe.add_component("prompt_builder", DynamicChatPromptBuilder())
+    pipe.add_component("llm", OpenAIChatGenerator(model="gpt-3.5-turbo"))
+
+    pipe.connect("prompt_builder.prompt", "llm.messages")
+
+    messages = [
+        ChatMessage.from_system("Always respond in German even if some input data is in other languages."),
+        ChatMessage.from_user("Tell me about {{location}}"),
+    ]
+
+    response = pipe.run(
+        data={"prompt_builder": {"template_variables": {"location": "Berlin"}, "prompt_source": messages}}
+    )
+    assert "Berlin" in response["llm"]["replies"][0].content
+    assert response["tracer"]["trace_url"]
+
+    url = "https://cloud.langfuse.com/api/public/traces/"
+    trace_url = response["tracer"]["trace_url"]
+    parsed_url = urlparse(trace_url)
+    # trace id is the last part of the path (after the last '/')
+    uuid = os.path.basename(parsed_url.path)
+
+    try:
+        # GET request with Basic Authentication on the Langfuse API
+        response = requests.get(url+uuid, auth=HTTPBasicAuth(os.environ.get("LANGFUSE_PUBLIC_KEY"),
+                                                              os.environ.get("LANGFUSE_SECRET_KEY")))
+
+        assert response.status_code == 200, f"Failed to retrieve data from Langfuse API: {response.status_code}"
+    except requests.exceptions.RequestException as e:
+        assert False, f"Failed to retrieve data from Langfuse API: {e}"