feat: support Space rerank models (#2358)

Co-authored-by: chan <dadachann@users.noreply.github.com>

src/langbot/pkg/api/http/service/provider.py

@@ -232,8 +232,15 @@ class ModelProviderService:
 
         llm_models = await self.ap.llm_model_service.get_llm_models_by_provider(provider_uuid)
         embedding_models = await self.ap.embedding_models_service.get_embedding_models_by_provider(provider_uuid)
+        rerank_service = getattr(self.ap, 'rerank_models_service', None)
+        rerank_models = (
+            await rerank_service.get_rerank_models_by_provider(provider_uuid)
+            if rerank_service is not None
+            else []
+        )
         existing_llm_names = {model['name'] for model in llm_models}
         existing_embedding_names = {model['name'] for model in embedding_models}
+        existing_rerank_names = {model['name'] for model in rerank_models}
 
         filtered_models = []
         for model in scanned_models:
@@ -260,6 +267,8 @@ class ModelProviderService:
                     'already_added': (
                         model_name in existing_embedding_names
                         if scanned_type == 'embedding'
+                        else model_name in existing_rerank_names
+                        if scanned_type == 'rerank'
                         else model_name in existing_llm_names
                     ),
                 }

src/langbot/pkg/provider/modelmgr/modelmgr.py

@@ -193,6 +193,9 @@ class ModelManager:
         existing_embedding_models = {
             m['uuid']: m for m in await self.ap.embedding_models_service.get_embedding_models()
         }
+        existing_rerank_models = {
+            m['uuid']: m for m in await self.ap.rerank_models_service.get_rerank_models()
+        }
 
         created = 0
         updated = 0
@@ -258,6 +261,33 @@ class ModelManager:
                         await self.ap.embedding_models_service.update_embedding_model(space_model.uuid, dict(desired))
                         updated += 1
 
+            elif space_model.category == 'rerank':
+                existing = existing_rerank_models.get(space_model.uuid)
+                if existing is None:
+                    await self.ap.rerank_models_service.create_rerank_model(
+                        {
+                            'uuid': space_model.uuid,
+                            'name': space_model.model_id,
+                            'provider_uuid': space_model_provider.uuid,
+                            'extra_args': {},
+                            'prefered_ranking': space_model.featured_order,
+                        },
+                        preserve_uuid=True,
+                    )
+                    created += 1
+                elif existing.get('provider_uuid') == space_model_provider.uuid:
+                    desired = {
+                        'name': space_model.model_id,
+                        'provider_uuid': space_model_provider.uuid,
+                        'prefered_ranking': space_model.featured_order,
+                    }
+                    if (
+                        existing.get('name') != desired['name']
+                        or existing.get('prefered_ranking') != desired['prefered_ranking']
+                    ):
+                        await self.ap.rerank_models_service.update_rerank_model(space_model.uuid, dict(desired))
+                        updated += 1
+
         if created or updated:
             self.ap.logger.info(f'Synced models from LangBot Space: {created} added, {updated} updated.')
 

src/langbot/pkg/provider/modelmgr/requesters/litellmchat.py

@@ -943,16 +943,21 @@ class LiteLLMRequester(requester.ProviderAPIRequester):
         if api_key:
             headers['Authorization'] = f'Bearer {api_key}'
 
+        request_args = dict(extra_args)
+        rerank_url = request_args.pop('rerank_url', None)
+        rerank_path = request_args.pop('rerank_path', 'rerank')
+
         payload: dict[str, typing.Any] = {
             'model': model_name,
             'query': query,
             'documents': documents,
             'top_n': top_n,
         }
-        if extra_args:
-            payload.update(extra_args)
+        if request_args:
+            payload.update(request_args)
 
-        rerank_url = f'{base_url}/rerank'
+        if not rerank_url:
+            rerank_url = f'{base_url}/{str(rerank_path).strip("/")}'
 
         try:
             async with httpx.AsyncClient(timeout=timeout) as client: