Add option --retry-sleep (#3059)

Closes #2852

yt_dlp/downloader/common.py

@@ -19,6 +19,7 @@ from ..utils import (
     encodeFilename,
     error_to_compat_str,
     format_bytes,
+    int_or_none,
     sanitize_open,
     shell_quote,
     timeconvert,
@@ -64,6 +65,7 @@ class FileDownloader:
                         useful for bypassing bandwidth throttling imposed by
                         a webserver (experimental)
     progress_template:  See YoutubeDL.py
+    retry_sleep_functions: See YoutubeDL.py
 
     Subclasses of this one must re-define the real_download method.
     """
@@ -98,6 +100,8 @@ class FileDownloader:
     def to_screen(self, *args, **kargs):
         self.ydl.to_screen(*args, quiet=self.params.get('quiet'), **kargs)
 
+    __to_screen = to_screen
+
     @property
     def FD_NAME(self):
         return re.sub(r'(?<!^)(?=[A-Z])', '_', type(self).__name__[:-2]).lower()
@@ -232,7 +236,8 @@ class FileDownloader:
                         self.to_screen(
                             f'[download] Unable to {action} file due to file access error. '
                             f'Retrying (attempt {retry} of {self.format_retries(file_access_retries)}) ...')
-                        time.sleep(0.01)
+                        if not self.sleep_retry('file_access', retry):
+                            time.sleep(0.01)
             return inner
         return outer
 
@@ -390,14 +395,23 @@ class FileDownloader:
 
     def report_retry(self, err, count, retries):
         """Report retry in case of HTTP error 5xx"""
-        self.to_screen(
+        self.__to_screen(
             '[download] Got server HTTP error: %s. Retrying (attempt %d of %s) ...'
             % (error_to_compat_str(err), count, self.format_retries(retries)))
+        self.sleep_retry('http', count)
 
     def report_unable_to_resume(self):
         """Report it was impossible to resume download."""
         self.to_screen('[download] Unable to resume')
 
+    def sleep_retry(self, retry_type, count):
+        sleep_func = self.params.get('retry_sleep_functions', {}).get(retry_type)
+        delay = int_or_none(sleep_func(n=count - 1)) if sleep_func else None
+        if delay:
+            self.__to_screen(f'Sleeping {delay} seconds ...')
+            time.sleep(delay)
+        return sleep_func is not None
+
     @staticmethod
     def supports_manifest(manifest):
         """ Whether the downloader can download the fragments from the manifest.