server : clarify /slots endpoint, add is_processing (#10162)

* server : clarify /slots endpoint, add is_processing

* fix tests

examples/server/README.md

@@ -692,7 +692,10 @@ Given a ChatML-formatted json description in `messages`, it returns the predicte
 
 ### GET `/slots`: Returns the current slots processing state
 
-This endpoint can be disabled with `--no-slots`
+> [!WARNING]
+> This endpoint is intended for debugging and may be modified in future versions. For security reasons, we strongly advise against enabling it in production environments.
+
+This endpoint is disabled by default and can be enabled with `--slots`
 
 If query param `?fail_on_no_slot=1` is set, this endpoint will respond with status code 503 if there is no available slots.
 
@@ -709,6 +712,7 @@ Example:
         "grammar": "",
         "id": 0,
         "ignore_eos": false,
+        "is_processing": false,
         "logit_bias": [],
         "min_p": 0.05000000074505806,
         "mirostat": 0,
@@ -741,7 +745,6 @@ Example:
             "temperature"
         ],
         "seed": 42,
-        "state": 1,
         "stop": [
             "\n"
         ],
@@ -755,10 +758,6 @@ Example:
 ]
 ```
 
-Possible values for `slot[i].state` are:
-- `0`: SLOT_STATE_IDLE
-- `1`: SLOT_STATE_PROCESSING
-
 ### GET `/metrics`: Prometheus compatible metrics exporter
 
 This endpoint is only accessible if `--metrics` is set.

examples/server/server.cpp

@@ -1568,7 +1568,7 @@ struct server_context {
                         json slot_data = get_formated_generation(slot);
                         slot_data["id"]            = slot.id;
                         slot_data["id_task"]       = slot.id_task;
-                        slot_data["state"]      = slot.state;
+                        slot_data["is_processing"] = slot.is_processing();
                         slot_data["prompt"]        = common_detokenize(ctx, slot.prompt_tokens);
                         slot_data["next_token"]    = {
                             {"has_next_token", slot.has_next_token},
@@ -1581,10 +1581,10 @@ struct server_context {
                             {"stopping_word",  slot.stopping_word},
                         };
 
-                        if (slot_data["state"] == SLOT_STATE_IDLE) {
+                        if (slot.is_processing()) {
-                            n_idle_slots++;
-                        } else {
                             n_processing_slots++;
+                        } else {
+                            n_idle_slots++;
                         }
 
                         slots_data.push_back(slot_data);

examples/server/tests/features/steps/steps.py

@@ -260,13 +260,13 @@ async def step_wait_for_server_status(context, expecting_status: Literal['health
 async def step_all_slots_status(context, expected_slot_status_string: Literal['idle', 'busy'] | str):
     match expected_slot_status_string:
         case 'idle':
-            expected_slot_status = 0
+            expected_slot_status = False
         case 'busy':
-            expected_slot_status = 1
+            expected_slot_status = True
         case _:
             assert False, "unknown status"
 
-    expected_slots = [{'id': slot_id, 'state': expected_slot_status}
+    expected_slots = [{'id': slot_id, 'is_processing': expected_slot_status}
                       for slot_id in range(context.n_slots)]
     await request_slots_status(context, expected_slots)
 
@@ -1354,8 +1354,8 @@ async def wait_for_slots_status(context,
                 if status_code == 503 and status_code == expected_http_status_code:
                     return
                 if status_code == 200 and status_code == expected_http_status_code:
-                    n_slots_idle = sum(1 if slot["state"] == 0 else 0 for slot in slots)
+                    n_slots_idle = sum(1 if not slot["is_processing"] else 0 for slot in slots)
-                    n_slots_processing = sum(1 if slot["state"] != 0 else 0 for slot in slots)
+                    n_slots_processing = sum(1 if slot["is_processing"] else 0 for slot in slots)
                     if ((slots_idle is None or slots_idle == n_slots_idle)
                         and (slots_processing is None or slots_processing == n_slots_processing)):
                         return