Add support for Application Default Credentials (ADC)

Author: Prabhjit Singh Dhillon

.changeset/new-adc-support.md

@@ -0,0 +1,12 @@
+---
+"@google/generative-ai": minor
+---
+
+Added support for Application Default Credentials (ADC). This enables more secure authentication when running on Google Cloud environments like GKE or GCE, without the need to manage API keys.
+
+To use ADC:
+1. Install the google-auth-library package 
+2. Initialize the SDK with `new GoogleGenerativeAI(undefined, { useAdc: true })`
+3. Set up ADC through gcloud CLI or service account credentials
+
+See documentation for more details. 

README.md

@@ -28,13 +28,15 @@ seamlessly across text, images, and code.
 See the [Node.js quickstart](https://ai.google.dev/tutorials/node_quickstart)
 for complete code.
 
+### Using API Key Authentication
+
 1.  Install the SDK package
 
 ```js
 npm install @google/generative-ai
 ```
 
-1.  Initialize the model
+2.  Initialize the model
 
 ```js
 const { GoogleGenerativeAI } = require("@google/generative-ai");
@@ -44,7 +46,7 @@ const genAI = new GoogleGenerativeAI(process.env.API_KEY);
 const model = genAI.getGenerativeModel({ model: "gemini-1.5-flash" });
 ```
 
-1.  Run a prompt
+3.  Run a prompt
 
 ```js
 const prompt = "Does this look store-bought or homemade?";
@@ -59,6 +61,30 @@ const result = await model.generateContent([prompt, image]);
 console.log(result.response.text());
 ```
 
+### Using Application Default Credentials (ADC)
+
+For improved security when running on Google Cloud environments (GKE, GCE, etc.) or for local development, you can use Application Default Credentials (ADC) instead of API keys:
+
+
+
+1. Initialize with ADC
+
+```js
+const { GoogleGenerativeAI } = require("@google/generative-ai");
+
+// Initialize with ADC (no API key needed)
+const genAI = new GoogleGenerativeAI(undefined, { useAdc: true });
+
+const model = genAI.getGenerativeModel({ model: "gemini-1.5-flash" });
+```
+
+3. Set up your credentials
+   - For local development: `gcloud auth application-default login`
+   - For GKE/GCE: Use service account credentials
+   - For more details, see [Application Default Credentials](https://cloud.google.com/docs/authentication/application-default-credentials)
+
+A complete sample is available in the [samples/adc_auth.js](./samples/adc_auth.js) file.
+
 ## Try out a sample app
 
 This repository contains sample Node and web apps demonstrating how the SDK can