[downloader/fragment] Document fragment_retries
[youtube-dl] / youtube_dl / downloader / fragment.py
1 from __future__ import division, unicode_literals
2
3 import os
4 import time
5
6 from .common import FileDownloader
7 from .http import HttpFD
8 from ..utils import (
9     encodeFilename,
10     sanitize_open,
11 )
12
13
14 class HttpQuietDownloader(HttpFD):
15     def to_screen(self, *args, **kargs):
16         pass
17
18
19 class FragmentFD(FileDownloader):
20     """
21     A base file downloader class for fragmented media (e.g. f4m/m3u8 manifests).
22
23     Available options:
24
25     fragment_retries:   Number of times to retry a fragment for HTTP error (DASH only)
26     """
27
28     def report_retry_fragment(self, fragment_name, count, retries):
29         self.to_screen(
30             '[download] Got server HTTP error. Retrying fragment %s (attempt %d of %s)...'
31             % (fragment_name, count, self.format_retries(retries)))
32
33     def _prepare_and_start_frag_download(self, ctx):
34         self._prepare_frag_download(ctx)
35         self._start_frag_download(ctx)
36
37     def _prepare_frag_download(self, ctx):
38         if 'live' not in ctx:
39             ctx['live'] = False
40         self.to_screen(
41             '[%s] Total fragments: %s'
42             % (self.FD_NAME, ctx['total_frags'] if not ctx['live'] else 'unknown (live)'))
43         self.report_destination(ctx['filename'])
44         dl = HttpQuietDownloader(
45             self.ydl,
46             {
47                 'continuedl': True,
48                 'quiet': True,
49                 'noprogress': True,
50                 'ratelimit': self.params.get('ratelimit'),
51                 'retries': self.params.get('retries', 0),
52                 'test': self.params.get('test', False),
53             }
54         )
55         tmpfilename = self.temp_name(ctx['filename'])
56         dest_stream, tmpfilename = sanitize_open(tmpfilename, 'wb')
57         ctx.update({
58             'dl': dl,
59             'dest_stream': dest_stream,
60             'tmpfilename': tmpfilename,
61         })
62
63     def _start_frag_download(self, ctx):
64         total_frags = ctx['total_frags']
65         # This dict stores the download progress, it's updated by the progress
66         # hook
67         state = {
68             'status': 'downloading',
69             'downloaded_bytes': 0,
70             'frag_index': 0,
71             'frag_count': total_frags,
72             'filename': ctx['filename'],
73             'tmpfilename': ctx['tmpfilename'],
74         }
75
76         start = time.time()
77         ctx.update({
78             'started': start,
79             # Total complete fragments downloaded so far in bytes
80             'complete_frags_downloaded_bytes': 0,
81             # Amount of fragment's bytes downloaded by the time of the previous
82             # frag progress hook invocation
83             'prev_frag_downloaded_bytes': 0,
84         })
85
86         def frag_progress_hook(s):
87             if s['status'] not in ('downloading', 'finished'):
88                 return
89
90             time_now = time.time()
91             state['elapsed'] = time_now - start
92             frag_total_bytes = s.get('total_bytes') or 0
93             if not ctx['live']:
94                 estimated_size = (
95                     (ctx['complete_frags_downloaded_bytes'] + frag_total_bytes) /
96                     (state['frag_index'] + 1) * total_frags)
97                 state['total_bytes_estimate'] = estimated_size
98
99             if s['status'] == 'finished':
100                 state['frag_index'] += 1
101                 state['downloaded_bytes'] += frag_total_bytes - ctx['prev_frag_downloaded_bytes']
102                 ctx['complete_frags_downloaded_bytes'] = state['downloaded_bytes']
103                 ctx['prev_frag_downloaded_bytes'] = 0
104             else:
105                 frag_downloaded_bytes = s['downloaded_bytes']
106                 state['downloaded_bytes'] += frag_downloaded_bytes - ctx['prev_frag_downloaded_bytes']
107                 if not ctx['live']:
108                     state['eta'] = self.calc_eta(
109                         start, time_now, estimated_size,
110                         state['downloaded_bytes'])
111                 state['speed'] = s.get('speed') or ctx.get('speed')
112                 ctx['speed'] = state['speed']
113                 ctx['prev_frag_downloaded_bytes'] = frag_downloaded_bytes
114             self._hook_progress(state)
115
116         ctx['dl'].add_progress_hook(frag_progress_hook)
117
118         return start
119
120     def _finish_frag_download(self, ctx):
121         ctx['dest_stream'].close()
122         elapsed = time.time() - ctx['started']
123         self.try_rename(ctx['tmpfilename'], ctx['filename'])
124         fsize = os.path.getsize(encodeFilename(ctx['filename']))
125
126         self._hook_progress({
127             'downloaded_bytes': fsize,
128             'total_bytes': fsize,
129             'filename': ctx['filename'],
130             'status': 'finished',
131             'elapsed': elapsed,
132         })