Add stop parameter to completions route

docs/openapi.json

@@ -1121,6 +1121,15 @@
             "description": "An alternative to sampling with temperature, called nucleus sampling, where the model considers the results of the\ntokens with top_p probability mass. So 0.1 means only the tokens comprising the top 10% probability mass are considered.",
             "example": 0.95,
             "nullable": true
+          },
+          "stop": {
+            "type": "array",
+            "items": {
+              "type": "string"
+            },
+            "description": "Up to 4 sequences where the API will stop generating further tokens.",
+            "example": "null",
+            "nullable": true
           }
         }
       },

router/src/lib.rs

@@ -401,6 +401,11 @@ pub struct CompletionRequest {
     #[serde(default)]
     #[schema(example = "1.0")]
     pub frequency_penalty: Option<f32>,
+
+    /// Up to 4 sequences where the API will stop generating further tokens.
+    #[serde(default)]
+    #[schema(nullable = true, example = "null")]
+    pub stop: Option<Vec<String>>,
 }
 
 #[derive(Clone, Deserialize, Serialize, ToSchema, Default)]

router/src/server.rs

@@ -597,9 +597,22 @@ async fn completions(
     let span = tracing::Span::current();
     metrics::increment_counter!("tgi_request_count");
 
-    let stream = req.stream;
-    let max_new_tokens = req.max_tokens.or(Some(100));
-    let seed = req.seed;
+	let CompletionRequest {
+        max_tokens,
+        seed,
+        stop,
+        stream,
+        temperature,
+        ..
+    } = req;
+
+    let max_new_tokens = max_tokens.or(Some(100));
+    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),
+    };
 
     // if suffix is present throw an error
     if req.suffix.is_some() {
@@ -629,22 +642,22 @@ async fn completions(
     }
 
     let generate_requests: Vec<GenerateRequest> = req
-        .prompt
+    	.prompt
         .iter()
         .map(|prompt| GenerateRequest {
             inputs: prompt.to_string(),
             parameters: GenerateParameters {
                 best_of: None,
-                temperature: req.temperature,
+                temperature: temperature,
                 repetition_penalty: req.repetition_penalty,
                 frequency_penalty: req.frequency_penalty,
                 top_k: None,
                 top_p: req.top_p,
                 typical_p: None,
-                do_sample: true,
+                do_sample,
                 max_new_tokens,
                 return_full_text: None,
-                stop: Vec::new(),
+                stop: stop.clone(),
                 truncate: None,
                 watermark: false,
                 details: true,