[Logging] Log rotation on all components (#12101)

* In Progress.

* Done.

* Fix the issue.

* Add wait for condition because logs are not written right away now.

* debug string.

* lint.

* Fix flaky test.

* Fix issues.

* Fix test.

* lint.

python/ray/ray_logging.py

@@ -25,6 +25,36 @@ def setup_logger(logging_level, logging_format):
     logger.propagate = False
 
 
+def setup_component_logger(*, logging_level, logging_format, log_dir, filename,
+                           max_bytes, backup_count):
+    """Configure the root logger that is used for Ray's python components.
+
+    For example, it should be used for monitor, dashboard, and log monitor.
+    The only exception is workers. They use the different logging config.
+
+    Args:
+        logging_level(str | int): Logging level in string or logging enum.
+        logging_format(str): Logging format string.
+        log_dir(str): Log directory path.
+        filename(str): Name of the file to write logs.
+        max_bytes(int): Same argument as RotatingFileHandler's maxBytes.
+        backup_count(int): Same argument as RotatingFileHandler's backupCount.
+    """
+    # Get the root logger.
+    logger = logging.getLogger("")
+    if type(logging_level) is str:
+        logging_level = logging.getLevelName(logging_level.upper())
+    assert filename, "filename argument should not be None."
+    assert log_dir, "log_dir should not be None."
+    handler = logging.handlers.RotatingFileHandler(
+        os.path.join(log_dir, filename),
+        maxBytes=max_bytes,
+        backupCount=backup_count)
+    logger.setLevel(logging_level)
+    handler.setFormatter(logging.Formatter(logging_format))
+    logger.addHandler(handler)
+
+
 """
 All components underneath here is used specifically for the default_worker.py.
 """