(docs) langfuse + proxy - log metadata

docs/my-website/docs/proxy/logging.md

@@ -1,4 +1,7 @@
 import Image from '@theme/IdealImage';
+import Tabs from '@theme/Tabs';
+import TabItem from '@theme/TabItem';
+
 
 # Logging - Custom Callbacks, OpenTelemetry, Langfuse, Sentry
 
@@ -490,6 +493,89 @@ Expected output on Langfuse
 
 <Image img={require('../../img/langfuse_small.png')} />
 
+### Logging Metadata to Langfuse
+
+
+<Tabs>
+
+<TabItem value="Curl" label="Curl Request">
+
+Pass `metadata` as part of the request body
+
+```shell
+curl --location 'http://0.0.0.0:8000/chat/completions' \
+    --header 'Content-Type: application/json' \
+    --data '{
+    "model": "gpt-3.5-turbo",
+    "messages": [
+        {
+        "role": "user",
+        "content": "what llm are you"
+        }
+    ],
+    "metadata": {
+        "generation_name": "ishaan-test-generation",
+        "generation_id": "gen-id22",
+        "trace_id": "trace-id22",
+        "trace_user_id": "user-id2"
+    }
+}'
+```
+</TabItem>
+<TabItem value="openai" label="OpenAI v1.0.0+">
+
+```python
+import openai
+client = openai.OpenAI(
+    api_key="anything",
+    base_url="http://0.0.0.0:8000"
+)
+
+# request sent to model set on litellm proxy, `litellm --model`
+response = client.chat.completions.create(model="gpt-3.5-turbo", messages = [
+    {
+        "role": "user",
+        "content": "this is a test request, write a short poem"
+    }
+])
+
+print(response)
+
+```
+</TabItem>
+<TabItem value="langchain" label="Langchain">
+
+```python
+from langchain.chat_models import ChatOpenAI
+from langchain.prompts.chat import (
+    ChatPromptTemplate,
+    HumanMessagePromptTemplate,
+    SystemMessagePromptTemplate,
+)
+from langchain.schema import HumanMessage, SystemMessage
+
+chat = ChatOpenAI(
+    openai_api_base="http://0.0.0.0:8000", # set openai_api_base to the LiteLLM Proxy
+    model = "gpt-3.5-turbo",
+    temperature=0.1
+)
+
+messages = [
+    SystemMessage(
+        content="You are a helpful assistant that im using to make a test request to."
+    ),
+    HumanMessage(
+        content="test from litellm. tell me why it's amazing in 1 sentence"
+    ),
+]
+response = chat(messages)
+
+print(response)
+```
+
+</TabItem>
+</Tabs>
+
 ## Logging Proxy Input/Output - DynamoDB
 
 We will use the `--config` to set