remove debug, reduce duplicate code -> init_check, add docs example for save_to_file

docs/includes/pairlists.md

@@ -208,7 +208,42 @@ In "append" mode, the retrieved pairlist is added to the original pairlist. All
 
 The `pairlist_url` option specifies the URL of the remote server where the pairlist is located, or the path to a local file (if file:/// is prepended). This allows the user to use either a remote server or a local file as the source for the pairlist.
 
-The `save_to_file` option, when provided with a valid filename, saves the processed pairlist to that file in JSON format. This option is optional, and by default, the pairlist is not saved.
+The `save_to_file` option, when provided with a valid filename, saves the processed pairlist to that file in JSON format. This option is optional, and by default, the pairlist is not saved to a file.
+
+??? Note
+    Example:
+    
+    `save_to_file` can be used to save the pairlist to a file with Bot1:
+
+    ```json
+    "pairlists": [
+        {
+            "method": "RemotePairList",
+            "mode": "whitelist",
+            "pairlist_url": "https://example.com/pairlist",
+            "number_assets": 10,
+            "refresh_period": 1800,
+            "keep_pairlist_on_failure": true,
+            "read_timeout": 60,
+            "save_to_file": "user_data/filename.json" 
+        }
+    ]
+    ```
+
+    This saved pairlist file can be loaded by Bot2, or any additional bot with this configuration:
+
+    ```json
+    "pairlists": [
+        {
+            "method": "RemotePairList",
+            "mode": "whitelist",
+            "pairlist_url": "file:///user_data/filename.json",
+            "number_assets": 10,
+            "refresh_period": 10,
+            "keep_pairlist_on_failure": true,
+        }
+    ]
+    ```    
 
 The user is responsible for providing a server or local file that returns a JSON object with the following structure:
 

freqtrade/plugins/pairlist/RemotePairList.py

@@ -185,31 +185,27 @@ class RemotePairList(IPairList):
                 try:
                     pairlist = self.process_json(jsonparse)
                 except Exception as e:
-
+                    pairlist = self.init_check(f'Failed processing JSON data: {type(e)}')
-                    if self._init_done:
-                        pairlist = self.return_last_pairlist()
-                        logger.warning(f'Error while processing JSON data: {type(e)}')
-                    else:
-                        raise OperationalException(f'Error while processing JSON data: {type(e)}')
-
             else:
-                if self._init_done:
+                pairlist = self.init_check(f'RemotePairList is not of type JSON: '
-                    self.log_once(f'Error: RemotePairList is not of type JSON: '
+                                           f' {self._pairlist_url}')
-                                  f' {self._pairlist_url}', logger.info)
-                    pairlist = self.return_last_pairlist()
-                else:
-                    raise OperationalException('RemotePairList is not of type JSON, abort.')
 
         except requests.exceptions.RequestException:
-            self.log_once(f'Was not able to fetch pairlist from:'
+            pairlist = self.init_check(f'Was not able to fetch pairlist from:'
-                          f' {self._pairlist_url}', logger.info)
+                                       f' {self._pairlist_url}')
-
-            pairlist = self.return_last_pairlist()
 
             time_elapsed = 0
 
         return pairlist, time_elapsed
 
+    def init_check(self, error: str):
+        if self._init_done:
+            self.log_once("Error: " + error, logger.info)
+            pairlist = self.return_last_pairlist()
+        else:
+            raise OperationalException(error)
+        return pairlist
+
     def gen_pairlist(self, tickers: Tickers) -> List[str]:
         """
         Generate the pairlist
@@ -242,15 +238,10 @@ class RemotePairList(IPairList):
                             jsonparse = rapidjson.load(json_file, parse_mode=CONFIG_PARSE_MODE)
                             pairlist = self.process_json(jsonparse)
                         except Exception as e:
-                            if self._init_done:
+                            pairlist = self.init_check(f'processing JSON data: {type(e)}')
-                                pairlist = self.return_last_pairlist()
-                                logger.warning(f'Error while processing JSON data: {type(e)}')
-                                logger.debug(f'Error while processing JSON data: {e}')
-                            else:
-                                raise OperationalException('Error while processing'
-                                                           f'JSON data: {type(e)}')
                 else:
-                    raise ValueError(f"{self._pairlist_url} does not exist.")
+                    pairlist = self.init_check(f"{self._pairlist_url} does not exist.")
+
             else:
                 # Fetch Pairlist from Remote URL
                 pairlist, time_elapsed = self.fetch_pairlist()