fix: gemini embeddings does not work for multiple documents (#386)

* fix: gemini embeddings does not work for multiple documents

* refactor: remove unnecessary printlns

rig-core/src/providers/gemini/embedding.rs

@@ -41,26 +41,37 @@ impl embeddings::EmbeddingModel for EmbeddingModel {
         }
     }
 
+    /// <https://ai.google.dev/api/embeddings#batch_embed_contents-SHELL>
     #[cfg_attr(feature = "worker", worker::send)]
     async fn embed_texts(
         &self,
         documents: impl IntoIterator<Item = String> + Send,
     ) -> Result<Vec<embeddings::Embedding>, EmbeddingError> {
-        let documents: Vec<_> = documents.into_iter().collect();
-        let mut request_body = json!({
-            "model": format!("models/{}", self.model),
-            "content": {
-                "parts": documents.iter().map(|doc| json!({ "text": doc })).collect::<Vec<_>>(),
-            },
-        });
+        let documents: Vec<String> = documents.into_iter().collect();
 
-        if let Some(ndims) = self.ndims {
-            request_body["output_dimensionality"] = json!(ndims);
-        }
+        // Google batch embed requests. See docstrings for API ref link.
+        let requests: Vec<_> = documents
+            .iter()
+            .map(|doc| {
+                json!({
+                    "model": format!("models/{}", self.model),
+                    "content": json!({
+                        "parts": [json!({
+                            "text": doc.to_string()
+                        })]
+                    }),
+                    "output_dimensionality": self.ndims,
+                })
+            })
+            .collect();
+
+        let request_body = json!({ "requests": requests  });
+
+        println!("{}", serde_json::to_string_pretty(&request_body).unwrap());
 
         let response = self
             .client
-            .post(&format!("/v1beta/models/{}:embedContent", self.model))
+            .post(&format!("/v1beta/models/{}:batchEmbedContents", self.model))
             .json(&request_body)
             .send()
             .await?
@@ -70,15 +81,16 @@ impl embeddings::EmbeddingModel for EmbeddingModel {
 
         match response {
             ApiResponse::Ok(response) => {
-                let chunk_size = self.ndims.unwrap_or_else(|| self.ndims());
-                Ok(documents
+                let docs = documents
                     .into_iter()
-                    .zip(response.embedding.values.chunks(chunk_size))
+                    .zip(response.embeddings)
                     .map(|(document, embedding)| embeddings::Embedding {
                         document,
-                        vec: embedding.to_vec(),
+                        vec: embedding.values,
                     })
-                    .collect())
+                    .collect();
+
+                Ok(docs)
             }
             ApiResponse::Err(err) => Err(EmbeddingError::ProviderError(err.message)),
         }
@@ -196,7 +208,7 @@ mod gemini_api_types {
 
     #[derive(Debug, Deserialize)]
     pub struct EmbeddingResponse {
-        pub embedding: EmbeddingValues,
+        pub embeddings: Vec<EmbeddingValues>,
     }
 
     #[derive(Debug, Deserialize)]