give users ability to decide how many models to keep in dry/live

config_examples/config_freqai.example.json

@@ -48,7 +48,7 @@
     ],
     "freqai": {
         "enabled": true,
-        "purge_old_models": true,
+        "purge_old_models": 2,
         "train_period_days": 15,
         "backtest_period_days": 7,
         "live_retrain_hours": 0,

docs/freqai-configuration.md

@@ -9,7 +9,7 @@ FreqAI is configured through the typical [Freqtrade config file](configuration.m
 ```json
     "freqai": {
         "enabled": true,
-        "purge_old_models": true,
+        "purge_old_models": 2,
         "train_period_days": 30,
         "backtest_period_days": 7,
         "identifier" : "unique-id",

docs/freqai-parameter-table.md

@@ -15,7 +15,7 @@ Mandatory parameters are marked as **Required** and have to be set in one of the
 | `identifier` | **Required.** <br> A unique ID for the current model. If models are saved to disk, the `identifier` allows for reloading specific pre-trained models/data. <br> **Datatype:** String.
 | `live_retrain_hours` | Frequency of retraining during dry/live runs. <br> **Datatype:** Float > 0. <br> Default: `0` (models retrain as often as possible).
 | `expiration_hours` | Avoid making predictions if a model is more than `expiration_hours` old. <br> **Datatype:** Positive integer. <br> Default: `0` (models never expire).
-| `purge_old_models` | Delete all unused models during live runs (not relevant to backtesting). If set to false (not default), dry/live runs will accumulate all unused models to disk. If <br> **Datatype:** Boolean. <br> Default: `True`.
+| `purge_old_models` | Number of models to keep on disk (not relevant to backtesting). Default is 2, dry/live runs will keep 2 models on disk. Setting to 0 keeps all models. If <br> **Datatype:** Boolean. <br> Default: `2`.
 | `save_backtest_models` | Save models to disk when running backtesting. Backtesting operates most efficiently by saving the prediction data and reusing them directly for subsequent runs (when you wish to tune entry/exit parameters). Saving backtesting models to disk also allows to use the same model files for starting a dry/live instance with the same model `identifier`. <br> **Datatype:** Boolean. <br> Default: `False` (no models are saved).
 | `fit_live_predictions_candles` | Number of historical candles to use for computing target (label) statistics from prediction data, instead of from the training dataset (more information can be found [here](freqai-configuration.md#creating-a-dynamic-target-threshold)). <br> **Datatype:** Positive integer.
 | `continual_learning` | Use the final state of the most recently trained model as starting point for the new model, allowing for incremental learning (more information can be found [here](freqai-running.md#continual-learning)). <br> **Datatype:** Boolean. <br> Default: `False`.

freqtrade/constants.py

@@ -546,7 +546,7 @@ CONF_SCHEMA = {
                 "enabled": {"type": "boolean", "default": False},
                 "keras": {"type": "boolean", "default": False},
                 "write_metrics_to_disk": {"type": "boolean", "default": False},
-                "purge_old_models": {"type": "boolean", "default": True},
+                "purge_old_models": {"type": ["boolean", "number"], "default": 2},
                 "conv_width": {"type": "integer", "default": 1},
                 "train_period_days": {"type": "integer", "default": 0},
                 "backtest_period_days": {"type": "number", "default": 7},

freqtrade/freqai/data_drawer.py

@@ -366,6 +366,12 @@ class FreqaiDataDrawer:
 
     def purge_old_models(self) -> None:
 
+        num_keep = self.freqai_info["purge_old_models"]
+        if not num_keep:
+            return
+        elif type(num_keep) == bool:
+            num_keep = 2
+
         model_folders = [x for x in self.full_path.iterdir() if x.is_dir()]
 
         pattern = re.compile(r"sub-train-(\w+)_(\d{10})")
@@ -388,11 +394,11 @@ class FreqaiDataDrawer:
                 delete_dict[coin]["timestamps"][int(timestamp)] = dir
 
         for coin in delete_dict:
-            if delete_dict[coin]["num_folders"] > 2:
+            if delete_dict[coin]["num_folders"] > num_keep:
                 sorted_dict = collections.OrderedDict(
                     sorted(delete_dict[coin]["timestamps"].items())
                 )
-                num_delete = len(sorted_dict) - 2
+                num_delete = len(sorted_dict) - num_keep
                 deleted = 0
                 for k, v in sorted_dict.items():
                     if deleted >= num_delete:

freqtrade/freqai/freqai_interface.py

@@ -629,8 +629,7 @@ class IFreqaiModel(ABC):
         if self.plot_features:
             plot_feature_importance(model, pair, dk, self.plot_features)
 
-        if self.freqai_info.get("purge_old_models", False):
-            self.dd.purge_old_models()
+        self.dd.purge_old_models()
 
     def set_initial_historic_predictions(
         self, pred_df: DataFrame, dk: FreqaiDataKitchen, pair: str, strat_df: DataFrame

freqtrade/templates/FreqaiExampleHybridStrategy.py

@@ -27,7 +27,7 @@ class FreqaiExampleHybridStrategy(IStrategy):
 
     "freqai": {
         "enabled": true,
-        "purge_old_models": true,
+        "purge_old_models": 2,
         "train_period_days": 15,
         "identifier": "uniqe-id",
         "feature_parameters": {

tests/freqai/conftest.py

@@ -27,7 +27,7 @@ def freqai_conf(default_conf, tmpdir):
             "timerange": "20180110-20180115",
             "freqai": {
                 "enabled": True,
-                "purge_old_models": True,
+                "purge_old_models": 2,
                 "train_period_days": 2,
                 "backtest_period_days": 10,
                 "live_retrain_hours": 0,