feat: Add Gemini 3.0 streaming support for Vertex AI

rig-integrations/rig-vertexai/Cargo.toml

@@ -17,6 +17,13 @@ serde = { workspace = true, features = ["derive"] }
 serde_json = { workspace = true }
 tokio = { workspace = true, features = ["full"] }
 tracing = { workspace = true }
+anyhow = { workspace = true }
+async-stream = { workspace = true }
+futures = { workspace = true }
+http = "1.3.1"
+reqwest = { version = "0.12", features = ["json"] }
+reqwest-middleware = "0.4"
+async-trait = "0.1"
 
 [dev-dependencies]
 anyhow = { workspace = true }

rig-integrations/rig-vertexai/src/auth.rs

@@ -0,0 +1,23 @@
+//! GCP authentication for Vertex AI API requests
+//!
+//! This module provides authentication helpers for Vertex AI streaming requests.
+
+/// Placeholder for future authentication middleware
+/// 
+/// Note: GCP token fetching is currently handled directly in streaming.rs
+/// using Application Default Credentials (ADC) via google-cloud-auth.
+#[derive(Clone, Debug)]
+pub struct GcpAuthMiddleware;
+
+impl GcpAuthMiddleware {
+    /// Create a new GCP auth middleware
+    pub fn new() -> Self {
+        Self
+    }
+}
+
+impl Default for GcpAuthMiddleware {
+    fn default() -> Self {
+        Self::new()
+    }
+}

rig-integrations/rig-vertexai/src/client.rs

@@ -199,6 +199,11 @@ impl Client {
             })
             .await
     }
+
+    /// Get GCP access token from credentials for manual authentication
+    pub fn credentials(&self) -> &google_cloud_auth::credentials::Credentials {
+        &self.credentials
+    }
 }
 
 impl Default for Client {

rig-integrations/rig-vertexai/src/completion.rs

@@ -27,6 +27,10 @@ pub const GEMINI_2_5_FLASH_LITE: &str = "gemini-2.5-flash-lite";
 pub const GEMINI_2_5_FLASH: &str = "gemini-2.5-flash";
 /// `gemini-2.5-pro`
 pub const GEMINI_2_5_PRO: &str = "gemini-2.5-pro";
+/// `gemini-3-pro-preview`
+pub const GEMINI_3_PRO_PREVIEW: &str = "gemini-3-pro-preview";
+/// `gemini-3-flash-preview`
+pub const GEMINI_3_FLASH_PREVIEW: &str = "gemini-3-flash-preview";
 
 #[derive(Clone)]
 pub struct CompletionModel {

rig-integrations/rig-vertexai/src/lib.rs

@@ -1,5 +1,8 @@
+pub mod auth;
 pub mod client;
 pub mod completion;
+pub mod streaming;
 pub(crate) mod types;
 
 pub use client::{Client, ClientBuilder};
+pub use streaming::StreamingCompletionModel;