fix: enable chat requests in vertex endpoint (#2481)

* fix: enable chat requests in vertex endpoint

* feat: avoid unwrap and pre allocate future vec

router/src/lib.rs

@@ -55,13 +55,20 @@ impl std::str::FromStr for Attention {
 }
 
 #[derive(Clone, Deserialize, ToSchema)]
-pub(crate) struct VertexInstance {
+pub(crate) struct GenerateVertexInstance {
     #[schema(example = "What is Deep Learning?")]
     pub inputs: String,
     #[schema(nullable = true, default = "null", example = "null")]
     pub parameters: Option<GenerateParameters>,
 }
 
+#[derive(Clone, Deserialize, ToSchema)]
+#[serde(untagged)]
+enum VertexInstance {
+    Generate(GenerateVertexInstance),
+    Chat(ChatRequest),
+}
+
 #[derive(Deserialize, ToSchema)]
 pub(crate) struct VertexRequest {
     #[serde(rename = "instances")]

router/src/server.rs

@@ -8,7 +8,7 @@ use crate::kserve::{
     kserve_model_metadata, kserve_model_metadata_ready,
 };
 use crate::validation::ValidationError;
-use crate::{default_tool_prompt, ChatTokenizeResponse};
+use crate::{default_tool_prompt, ChatTokenizeResponse, VertexInstance};
 use crate::{
     usage_stats, BestOfSequence, Details, ErrorResponse, FinishReason, FunctionName,
     GenerateParameters, GenerateRequest, GenerateResponse, GrammarType, HubModelInfo,
@@ -1406,12 +1406,12 @@ async fn vertex_compatibility(
         ));
     }
 
-    // Process all instances
-    let predictions = req
-        .instances
-        .iter()
-        .map(|instance| {
-            let generate_request = GenerateRequest {
+    // Prepare futures for all instances
+    let mut futures = Vec::with_capacity(req.instances.len());
+
+    for instance in req.instances.iter() {
+        let generate_request = match instance {
+            VertexInstance::Generate(instance) => GenerateRequest {
                 inputs: instance.inputs.clone(),
                 add_special_tokens: true,
                 parameters: GenerateParameters {
@@ -1422,14 +1422,98 @@ async fn vertex_compatibility(
                     decoder_input_details: true,
                     ..Default::default()
                 },
+            },
+            VertexInstance::Chat(instance) => {
+                let ChatRequest {
+                    model,
+                    max_tokens,
+                    messages,
+                    seed,
+                    stop,
+                    stream,
+                    tools,
+                    tool_choice,
+                    tool_prompt,
+                    temperature,
+                    response_format,
+                    guideline,
+                    presence_penalty,
+                    frequency_penalty,
+                    top_p,
+                    top_logprobs,
+                    ..
+                } = instance.clone();
+
+                let repetition_penalty = presence_penalty.map(|x| x + 2.0);
+                let max_new_tokens = max_tokens.or(Some(100));
+                let tool_prompt = tool_prompt
+                    .filter(|s| !s.is_empty())
+                    .unwrap_or_else(default_tool_prompt);
+                let stop = stop.unwrap_or_default();
+                // enable greedy only when temperature is 0
+                let (do_sample, temperature) = match temperature {
+                    Some(temperature) if temperature == 0.0 => (false, None),
+                    other => (true, other),
+                };
+                let (inputs, grammar, _using_tools) = match prepare_chat_input(
+                    &infer,
+                    response_format,
+                    tools,
+                    tool_choice,
+                    &tool_prompt,
+                    guideline,
+                    messages,
+                ) {
+                    Ok(result) => result,
+                    Err(e) => {
+                        return Err((
+                            StatusCode::BAD_REQUEST,
+                            Json(ErrorResponse {
+                                error: format!("Failed to prepare chat input: {}", e),
+                                error_type: "Input preparation error".to_string(),
+                            }),
+                        ));
+                    }
                 };
 
-            async {
+                GenerateRequest {
+                    inputs: inputs.to_string(),
+                    add_special_tokens: false,
+                    parameters: GenerateParameters {
+                        best_of: None,
+                        temperature,
+                        repetition_penalty,
+                        frequency_penalty,
+                        top_k: None,
+                        top_p,
+                        typical_p: None,
+                        do_sample,
+                        max_new_tokens,
+                        return_full_text: None,
+                        stop,
+                        truncate: None,
+                        watermark: false,
+                        details: true,
+                        decoder_input_details: !stream,
+                        seed,
+                        top_n_tokens: top_logprobs,
+                        grammar,
+                        adapter_id: model.filter(|m| *m != "tgi").map(String::from),
+                    },
+                }
+            }
+        };
+
+        let infer_clone = infer.clone();
+        let compute_type_clone = compute_type.clone();
+        let span_clone = span.clone();
+
+        futures.push(async move {
             generate_internal(
-                    Extension(infer.clone()),
-                    compute_type.clone(),
+                Extension(infer_clone),
+                compute_type_clone,
                 Json(generate_request),
-                    span.clone(),
+                span_clone,
             )
             .await
             .map(|(_, Json(generation))| generation.generated_text)
@@ -1442,11 +1526,13 @@ async fn vertex_compatibility(
                     }),
                 )
             })
+        });
     }
-        })
-        .collect::<FuturesUnordered<_>>()
-        .try_collect::<Vec<_>>()
-        .await?;
+
+    // execute all futures in parallel, collect results, returning early if any error occurs
+    let results = futures::future::join_all(futures).await;
+    let predictions: Result<Vec<_>, _> = results.into_iter().collect();
+    let predictions = predictions?;
 
     let response = VertexResponse { predictions };
     Ok((HeaderMap::new(), Json(response)).into_response())