Move "slow-log" to it's own mixin

freqtrade/mixins/__init__.py

@@ -0,0 +1,2 @@
+# flake8: noqa: F401
+from freqtrade.mixins.logging_mixin import LoggingMixin

freqtrade/mixins/logging_mixin.py

@@ -0,0 +1,34 @@
+
+
+from cachetools import TTLCache, cached
+
+
+class LoggingMixin():
+    """
+    Logging Mixin
+    Shows similar messages only once every `refresh_period`.
+    """
+    def __init__(self, logger, refresh_period: int = 3600):
+        """
+        :param refresh_period: in seconds - Show identical messages in this intervals
+        """
+        self.logger = logger
+        self.refresh_period = refresh_period
+        self._log_cache: TTLCache = TTLCache(maxsize=1024, ttl=self.refresh_period)
+
+    def log_on_refresh(self, logmethod, message: str) -> None:
+        """
+        Logs message - not more often than "refresh_period" to avoid log spamming
+        Logs the log-message as debug as well to simplify debugging.
+        :param logmethod: Function that'll be called. Most likely `logger.info`.
+        :param message: String containing the message to be sent to the function.
+        :return: None.
+        """
+        @cached(cache=self._log_cache)
+        def _log_on_refresh(message: str):
+            logmethod(message)
+
+        # Log as debug first
+        self.logger.debug(message)
+        # Call hidden function.
+        _log_on_refresh(message)