Add option --retry-sleep (#3059)

Closes #2852

yt_dlp/YoutubeDL.py

@@ -453,6 +453,9 @@ class YoutubeDL:
                        Allowed keys are 'download', 'postprocess',
                        'download-title' (console title) and 'postprocess-title'.
                        The template is mapped on a dictionary with keys 'progress' and 'info'
+    retry_sleep_functions: Dictionary of functions that takes the number of attempts
+                       as argument and returns the time to sleep in seconds.
+                       Allowed keys are 'http', 'fragment', 'file_access'
 
     The following parameters are not used by YoutubeDL itself, they are used by
     the downloader (see yt_dlp/downloader/common.py):

yt_dlp/__init__.py

@@ -247,6 +247,28 @@ def validate_options(opts):
     opts.extractor_retries = parse_retries('extractor', opts.extractor_retries)
     opts.file_access_retries = parse_retries('file access', opts.file_access_retries)
 
+    # Retry sleep function
+    def parse_sleep_func(expr):
+        NUMBER_RE = r'\d+(?:\.\d+)?'
+        op, start, limit, step, *_ = tuple(re.fullmatch(
+            rf'(?:(linear|exp)=)?({NUMBER_RE})(?::({NUMBER_RE}))?(?::({NUMBER_RE}))?',
+            expr.strip()).groups()) + (None, None)
+
+        if op == 'exp':
+            return lambda n: min(float(start) * (float(step or 2) ** n), float(limit or 'inf'))
+        else:
+            default_step = start if op or limit else 0
+            return lambda n: min(float(start) + float(step or default_step) * n, float(limit or 'inf'))
+
+    for key, expr in opts.retry_sleep.items():
+        if not expr:
+            del opts.retry_sleep[key]
+            continue
+        try:
+            opts.retry_sleep[key] = parse_sleep_func(expr)
+        except AttributeError as e:
+            raise ValueError(f'invalid {key} retry sleep expression {expr!r}: {e}')
+
     # Bytes
     def parse_bytes(name, value):
         if value is None:
@@ -694,6 +716,7 @@ def parse_options(argv=None):
         'file_access_retries': opts.file_access_retries,
         'fragment_retries': opts.fragment_retries,
         'extractor_retries': opts.extractor_retries,
+        'retry_sleep_functions': opts.retry_sleep,
         'skip_unavailable_fragments': opts.skip_unavailable_fragments,
         'keep_fragments': opts.keep_fragments,
         'concurrent_fragment_downloads': opts.concurrent_fragment_downloads,

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.

yt_dlp/downloader/external.py

@@ -142,6 +142,7 @@ class ExternalFD(FragmentFD):
                 self.to_screen(
                     '[%s] Got error. Retrying fragments (attempt %d of %s)...'
                     % (self.get_basename(), count, self.format_retries(fragment_retries)))
+                self.sleep_retry('fragment', count)
         if count > fragment_retries:
             if not skip_unavailable_fragments:
                 self.report_error('Giving up after %s fragment retries' % fragment_retries)

yt_dlp/downloader/fragment.py

@@ -25,10 +25,6 @@ class HttpQuietDownloader(HttpFD):
 
     console_title = to_screen
 
-    def report_retry(self, err, count, retries):
-        super().to_screen(
-            f'[download] Got server HTTP error: {err}. Retrying (attempt {count} of {self.format_retries(retries)}) ...')
-
 
 class FragmentFD(FileDownloader):
     """
@@ -70,6 +66,7 @@ class FragmentFD(FileDownloader):
         self.to_screen(
             '\r[download] Got server HTTP error: %s. Retrying fragment %d (attempt %d of %s) ...'
             % (error_to_compat_str(err), frag_index, count, self.format_retries(retries)))
+        self.sleep_retry('fragment', count)
 
     def report_skip_fragment(self, frag_index, err=None):
         err = f' {err};' if err else ''

yt_dlp/options.py

@@ -828,6 +828,18 @@ def create_parser():
         '--fragment-retries',
         dest='fragment_retries', metavar='RETRIES', default=10,
         help='Number of retries for a fragment (default is %default), or "infinite" (DASH, hlsnative and ISM)')
+    downloader.add_option(
+        '--retry-sleep',
+        dest='retry_sleep', metavar='[TYPE:]EXPR', default={}, type='str',
+        action='callback', callback=_dict_from_options_callback,
+        callback_kwargs={
+            'allowed_keys': 'http|fragment|file_access',
+            'default_key': 'http',
+        }, help=(
+            'An expression for the time to sleep between retries in seconds (optionally) prefixed '
+            'by the type of retry (http (default), fragment, file_access) to apply the sleep to. '
+            'EXPR can be a number, or of the forms linear=START[:END[:STEP=1]] or exp=START[:END[:BASE=2]]. '
+            'Eg: --retry-sleep linear=1::2 --retry-sleep fragment:exp=1:20'))
     downloader.add_option(
         '--skip-unavailable-fragments', '--no-abort-on-unavailable-fragment',
         action='store_true', dest='skip_unavailable_fragments', default=True,