(feat) Add support for using @google/generative-ai JS with LiteLLM Proxy (#6899)

* feat - allow using gemini js SDK with LiteLLM

* add auth for gemini_proxy_route

* basic local test for js

* test cost tagging gemini js requests

* add js sdk test for gemini with litellm

* add docs on gemini JS SDK

* run node.js tests

* fix google ai studio tests

* fix vertex js spend test

docs/my-website/docs/pass_through/google_ai_studio.md

@@ -1,12 +1,21 @@
+import Image from '@theme/IdealImage';
+import Tabs from '@theme/Tabs';
+import TabItem from '@theme/TabItem';
+
+
 # Google AI Studio SDK
 
 Pass-through endpoints for Google AI Studio - call provider-specific endpoint, in native format (no translation).
 
-Just replace `https://generativelanguage.googleapis.com` with `LITELLM_PROXY_BASE_URL/gemini` 🚀
+Just replace `https://generativelanguage.googleapis.com` with `LITELLM_PROXY_BASE_URL/gemini`
 
 #### **Example Usage**
+
+<Tabs>
+<TabItem value="curl" label="curl">
+
 ```bash
-http://0.0.0.0:4000/gemini/v1beta/models/gemini-1.5-flash:countTokens?key=sk-anything' \
+curl 'http://0.0.0.0:4000/gemini/v1beta/models/gemini-1.5-flash:countTokens?key=sk-anything' \
 -H 'Content-Type: application/json' \
 -d '{
     "contents": [{
@@ -17,6 +26,53 @@ http://0.0.0.0:4000/gemini/v1beta/models/gemini-1.5-flash:countTokens?key=sk-any
 }'
 ```
 
+</TabItem>
+<TabItem value="js" label="Google AI Node.js SDK">
+
+```javascript
+const { GoogleGenerativeAI } = require("@google/generative-ai");
+
+const modelParams = {
+    model: 'gemini-pro',
+};
+  
+const requestOptions = {
+    baseUrl: 'http://localhost:4000/gemini', // http://<proxy-base-url>/gemini
+};
+  
+const genAI = new GoogleGenerativeAI("sk-1234"); // litellm proxy API key
+const model = genAI.getGenerativeModel(modelParams, requestOptions);
+
+async function main() {
+    try {
+        const result = await model.generateContent("Explain how AI works");
+        console.log(result.response.text());
+    } catch (error) {
+        console.error('Error:', error);
+    }
+}
+
+// For streaming responses
+async function main_streaming() {
+    try {
+        const streamingResult = await model.generateContentStream("Explain how AI works");
+        for await (const chunk of streamingResult.stream) {
+            console.log('Stream chunk:', JSON.stringify(chunk));
+        }
+        const aggregatedResponse = await streamingResult.response;
+        console.log('Aggregated response:', JSON.stringify(aggregatedResponse));
+    } catch (error) {
+        console.error('Error:', error);
+    }
+}
+
+main();
+// main_streaming();
+```
+
+</TabItem>
+</Tabs>
+
 Supports **ALL** Google AI Studio Endpoints (including streaming).
 
 [**See All Google AI Studio Endpoints**](https://ai.google.dev/api)
@@ -166,14 +222,14 @@ curl -X POST "https://generativelanguage.googleapis.com/v1beta/models/gemini-1.5
 ```
 
 
-## Advanced - Use with Virtual Keys 
+## Advanced 
 
 Pre-requisites
 - [Setup proxy with DB](../proxy/virtual_keys.md#setup)
 
 Use this, to avoid giving developers the raw Google AI Studio key, but still letting them use Google AI Studio endpoints.
 
-### Usage
+### Use with Virtual Keys
 
 1. Setup environment
 
@@ -220,4 +276,66 @@ http://0.0.0.0:4000/gemini/v1beta/models/gemini-1.5-flash:countTokens?key=sk-123
           }]
         }]
 }'
-```
+```
+
+
+### Send `tags` in request headers
+
+Use this if you want `tags` to be tracked in the LiteLLM DB and on logging callbacks.
+
+Pass tags in request headers as a comma separated list. In the example below the following tags will be tracked
+
+```
+tags: ["gemini-js-sdk", "pass-through-endpoint"]
+```
+
+<Tabs>
+<TabItem value="curl" label="curl">
+
+```bash
+curl 'http://0.0.0.0:4000/gemini/v1beta/models/gemini-1.5-flash:generateContent?key=sk-anything' \
+-H 'Content-Type: application/json' \
+-H 'tags: gemini-js-sdk,pass-through-endpoint' \
+-d '{
+    "contents": [{
+        "parts":[{
+          "text": "The quick brown fox jumps over the lazy dog."
+          }]
+        }]
+}'
+```
+
+</TabItem>
+<TabItem value="js" label="Google AI Node.js SDK">
+
+```javascript
+const { GoogleGenerativeAI } = require("@google/generative-ai");
+
+const modelParams = {
+    model: 'gemini-pro',
+};
+  
+const requestOptions = {
+    baseUrl: 'http://localhost:4000/gemini', // http://<proxy-base-url>/gemini
+    customHeaders: {
+        "tags": "gemini-js-sdk,pass-through-endpoint"
+    }
+};
+  
+const genAI = new GoogleGenerativeAI("sk-1234");
+const model = genAI.getGenerativeModel(modelParams, requestOptions);
+
+async function main() {
+    try {
+        const result = await model.generateContent("Explain how AI works");
+        console.log(result.response.text());
+    } catch (error) {
+        console.error('Error:', error);
+    }
+}
+
+main();
+```
+
+</TabItem>
+</Tabs>