Add custom format for warnings (#477)

[cellxgene] Warning: <message>

server/app/app.py

@@ -1,4 +1,5 @@
 import os
+import warnings
 
 from flask import Flask
 from flask_caching import Cache
@@ -7,11 +8,13 @@ from flask_cors import CORS
 from flask_restful_swagger_2 import get_swagger_blueprint
 
 from .rest_api.rest import get_api_resources
-from .util.utils import Float32JSONEncoder
+from .util.utils import Float32JSONEncoder, custom_format_warning
 from .web import webapp
 
 REACTIVE_LIMIT = 1_000_000
 
+warnings.formatwarning = custom_format_warning
+
 app = Flask(__name__, static_folder="web/static")
 app.json_encoder = Float32JSONEncoder
 cache = Cache(app, config={"CACHE_TYPE": "simple", "CACHE_DEFAULT_TIMEOUT": 860000})

server/app/util/utils.py

@@ -15,6 +15,10 @@ class Float32JSONEncoder(json.JSONEncoder):
         return json.JSONEncoder.default(self, obj)
 
 
+def custom_format_warning(msg, *args, **kwargs):
+    return f"[cellxgene] Warning: {msg} \n"
+
+
 def get_mime_type(default="application/json", acceptable_types=["application/json", "text/csv"], query_param=None,
                   header=None):
     mime_type = default