summaryrefslogtreecommitdiff
path: root/mirrors/utils.py
blob: 9f40bca648f48594365aef9bc4578ab95d6bd5bc (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
from datetime import timedelta

from django.db import connection
from django.db.models import Count, Max, Min
from django.utils.dateparse import parse_datetime
from django.utils.timezone import now
from django_countries.fields import Country

from main.utils import cache_function, database_vendor
from .models import MirrorLog, MirrorUrl


DEFAULT_CUTOFF = timedelta(hours=24)


def dictfetchall(cursor):
    "Returns all rows from a cursor as a dict."
    desc = cursor.description
    return [
        dict(zip([col[0] for col in desc], row))
        for row in cursor.fetchall()
    ]

@cache_function(178)
def status_data(cutoff_time, mirror_id=None):
    if mirror_id is not None:
        params = [cutoff_time, mirror_id]
        mirror_where = 'AND u.mirror_id = %s'
    else:
        params = [cutoff_time]
        mirror_where = ''

    vendor = database_vendor(MirrorUrl)
    if vendor == 'sqlite':
        sql = """
SELECT l.url_id, u.mirror_id,
    COUNT(l.id) AS check_count,
    COUNT(l.last_sync) AS success_count,
    MAX(l.last_sync) AS last_sync,
    MAX(l.check_time) AS last_check,
    AVG(l.duration) AS duration_avg,
    0.0 AS duration_stddev,
    AVG(STRFTIME('%%s', check_time) - STRFTIME('%%s', last_sync)) AS delay
FROM mirrors_mirrorlog l
JOIN mirrors_mirrorurl u ON u.id = l.url_id
WHERE l.check_time >= %s
""" + mirror_where + """
GROUP BY l.url_id, u.mirror_id
"""
    else:
        sql = """
SELECT l.url_id, u.mirror_id,
    COUNT(l.id) AS check_count,
    COUNT(l.last_sync) AS success_count,
    MAX(l.last_sync) AS last_sync,
    MAX(l.check_time) AS last_check,
    AVG(l.duration) AS duration_avg,
    STDDEV(l.duration) AS duration_stddev,
    AVG(check_time - last_sync) AS delay
FROM mirrors_mirrorlog l
JOIN mirrors_mirrorurl u ON u.id = l.url_id
WHERE l.check_time >= %s
""" + mirror_where + """
GROUP BY l.url_id, u.mirror_id
"""

    cursor = connection.cursor()
    cursor.execute(sql, params)
    url_data = dictfetchall(cursor)

    # sqlite loves to return less than ideal types
    if vendor == 'sqlite':
        for item in url_data:
            if item['delay'] is not None:
                item['delay'] = timedelta(seconds=item['delay'])
            if item['last_sync'] is not None:
                item['last_sync'] = parse_datetime(item['last_sync'])
            item['last_check'] = parse_datetime(item['last_check'])

    return {item['url_id']: item for item in url_data}


def annotate_url(url, url_data):
    '''Given a MirrorURL object, add a few more attributes to it regarding
    status, including completion_pct, delay, and score.'''
    known_attrs = (
        ('success_count', 0),
        ('check_count', 0),
        ('completion_pct', None),
        ('last_check', None),
        ('last_sync', None),
        ('delay', None),
        ('score', None),
    )
    for k, v in known_attrs:
        setattr(url, k, v)
    for k, v in url_data.items():
        if k not in ('url_id', 'mirror_id'):
            setattr(url, k, v)

    if url.check_count > 0:
        url.completion_pct = float(url.success_count) / url.check_count

    if url.delay is not None:
        hours = url.delay.days * 24.0 + url.delay.seconds / 3600.0

        if url.completion_pct > 0:
            divisor = url.completion_pct
        else:
            # arbitrary small value
            divisor = 0.005
        stddev = url.duration_stddev or 0.0
        url.score = (hours + url.duration_avg + stddev) / divisor


def get_mirror_statuses(cutoff=DEFAULT_CUTOFF, mirror_id=None, show_all=False):
    cutoff_time = now() - cutoff

    valid_urls = MirrorUrl.objects.filter(
            logs__check_time__gte=cutoff_time).distinct()

    if mirror_id:
        valid_urls = valid_urls.filter(mirror_id=mirror_id)
    if not show_all:
        valid_urls = valid_urls.filter(active=True, mirror__active=True,
                mirror__public=True)

    url_data = status_data(cutoff_time, mirror_id)
    urls = MirrorUrl.objects.select_related('mirror', 'protocol').filter(
            id__in=valid_urls).order_by('mirror__id', 'url')

    if urls:
        for url in urls:
            annotate_url(url, url_data.get(url.id, {}))
        last_check = max([u.last_check for u in urls if u.last_check])
        num_checks = max([u.check_count for u in urls])
        check_info = MirrorLog.objects.filter(check_time__gte=cutoff_time)
        if mirror_id:
            check_info = check_info.filter(url__mirror_id=mirror_id)
        check_info = check_info.aggregate(
                mn=Min('check_time'), mx=Max('check_time'))
        if num_checks > 1:
            check_frequency = (check_info['mx'] - check_info['mn']) \
                    / (num_checks - 1)
        else:
            check_frequency = None
    else:
        last_check = None
        num_checks = 0
        check_frequency = None

    return {
        'cutoff': cutoff,
        'last_check': last_check,
        'num_checks': num_checks,
        'check_frequency': check_frequency,
        'urls': urls,
    }


def get_mirror_errors(cutoff=DEFAULT_CUTOFF, mirror_id=None, show_all=False):
    cutoff_time = now() - cutoff
    errors = MirrorLog.objects.filter(
            is_success=False, check_time__gte=cutoff_time,
            url__mirror__public=True).values(
            'url__url', 'url__country', 'url__protocol__protocol',
            'url__mirror__tier', 'error').annotate(
            error_count=Count('error'), last_occurred=Max('check_time')
            ).order_by('-last_occurred', '-error_count')

    if mirror_id:
        errors = errors.filter(url__mirror_id=mirror_id)
    if not show_all:
        errors = errors.filter(url__active=True, url__mirror__active=True,
                url__mirror__public=True)

    errors = list(errors)
    for err in errors:
        err['country'] = Country(err['url__country'])
    return errors


@cache_function(295)
def get_mirror_url_for_download(cutoff=DEFAULT_CUTOFF):
    '''Find a good mirror URL to use for package downloads. If we have mirror
    status data available, it is used to determine a good choice by looking at
    the last batch of status rows.'''
    cutoff_time = now() - cutoff
    status_data = MirrorLog.objects.filter(
            check_time__gte=cutoff_time).aggregate(
            Max('check_time'), Max('last_sync'))
    if status_data['check_time__max'] is not None:
        min_check_time = status_data['check_time__max'] - timedelta(minutes=5)
        min_sync_time = status_data['last_sync__max'] - timedelta(minutes=20)
        best_logs = MirrorLog.objects.filter(is_success=True,
                check_time__gte=min_check_time, last_sync__gte=min_sync_time,
                url__active=True,
                url__mirror__public=True, url__mirror__active=True,
                url__protocol__default=True).order_by(
                'duration')[:1]
        if best_logs:
            return MirrorUrl.objects.get(id=best_logs[0].url_id)

    mirror_urls = MirrorUrl.objects.filter(active=True,
            mirror__public=True, mirror__active=True, protocol__default=True)
    # look first for a country-agnostic URL, then fall back to any HTTP URL
    filtered_urls = mirror_urls.filter(country='')[:1]
    if not filtered_urls:
        filtered_urls = mirror_urls[:1]
    if not filtered_urls:
        return None
    return filtered_urls[0]

# vim: set ts=4 sw=4 et: