improved hanlding of not responding node

scorum/api/request.py

@@ -16,20 +16,21 @@ def get_curl_cli(url, api, method, args):
 
 def call(url, api, method, args, retries=5):
     payload = to_payload(method, api, args)
-
+    r = 0
     while retries:
         try:
             r = requests.post(url, json=payload)
             retries = 0
         except Exception as e:
-            log.error("Error during request: %s", e)
-            log.warning("Remain attempts: %d", retries)
+            log.error("Error during request: %s\n Remain attempts: %d", e, retries)
             time.sleep(0.5)
             retries -= 1
 
+    if not isinstance(r, requests.Response):
+        raise ConnectionError("Failed to retrieve response from: %s", url)
+
     try:
         response = json.loads(r.text)
         return response["result"]
-    except:
+    except KeyError:
         log.error("request failed with code: %d: %s\n%s" % (r.status_code, r.reason, r.text))
-        return None