fix(#1023): handle elasticsearch connection problems on server startup (

#1030)

* fix: handle elasticsearch connection problems on server startup

* Apply suggestions from code review

Co-authored-by: Daniel Vila Suero <daniel@recogn.ai>

* Update src/rubrix/server/server.py

Co-authored-by: Daniel Vila Suero <daniel@recogn.ai>

* fix message

Co-authored-by: Daniel Vila Suero <daniel@recogn.ai>

(cherry picked from commit dd8aefc)

src/rubrix/server/server.py

@@ -20,11 +20,11 @@
 import os
 from pathlib import Path
 
+import elasticsearch
+from brotli_asgi import BrotliMiddleware
 from fastapi import FastAPI
 from fastapi.middleware.cors import CORSMiddleware
-from brotli_asgi import BrotliMiddleware
-
-from pydantic import ValidationError
+from pydantic import ConfigError, ValidationError
 
 from rubrix import __version__ as rubrix_version
 from rubrix.server.commons.errors import (
@@ -35,7 +35,9 @@
 from rubrix.server.commons.static_rewrite import RewriteStaticFiles
 from rubrix.server.datasets.dao import DatasetsDAO, create_datasets_dao
 from rubrix.server.security import auth
-from rubrix.server.tasks.commons.dao.dao import DatasetRecordsDAO, dataset_records_dao
+from rubrix.server.tasks.commons.dao.dao import DatasetRecordsDAO
+
+from .commons.settings import settings
 from .commons.settings import settings as api_settings
 from .routes import api_router
 
@@ -86,11 +88,19 @@ def configure_app_statics(app: FastAPI):
 def configure_app_startup(app: FastAPI):
     @app.on_event("startup")
     async def configure_elasticsearch():
-        es_wrapper = create_es_wrapper()
-        datasets: DatasetsDAO = create_datasets_dao(es=es_wrapper)
-        dataset_records: DatasetRecordsDAO = dataset_records_dao(es=es_wrapper)
-        datasets.init()
-        dataset_records.init()
+        try:
+            es_wrapper = create_es_wrapper()
+            dataset_records: DatasetRecordsDAO = DatasetRecordsDAO(es_wrapper)
+            datasets: DatasetsDAO = DatasetsDAO.get_instance(es_wrapper)
+            datasets.init()
+            dataset_records.init()
+        except elasticsearch.exceptions.ConnectionError as error:
+            raise ConfigError(
+                f"Your Elasticsearch endpoint at {settings.elasticsearch} is not available or not responding."
+                "\nPlease make sure your Elasticsearch instance is launched and correctly running and you have the necessary access permissions. "
+                "Once you have verified this, restart the Rubrix server."
+                f"\nError detail: [{error}]"
+            )
 
 
 def configure_app_security(app: FastAPI):