reflector-2020.12.7.tar.xz

3 files changed, 109 insertions, 31 deletions

diff --git a/CHANGELOG b/CHANGELOG
index 7438d43..1535d1c 100644
--- a/CHANGELOG
+++ b/CHANGELOG
@@ -1,3 +1,6 @@
+# 2020-12-07
+* Restored download timeout option.
+
 # 2020-12-03
 * Removed thread support from mirror speed test to avoid skewing results on saturated connections.
 * Changed the speed test target file to the community database for more reliable results.
diff --git a/Reflector.py b/Reflector.py
index bb56b56..95b6798 100644
--- a/Reflector.py
+++ b/Reflector.py
@@ -37,6 +37,7 @@ import re
 import shlex
 import socket
 import subprocess
+import signal
 import sys
 import tempfile
 import time
@@ -59,6 +60,7 @@ MIRROR_URL_FORMAT = '{0}{1}/os/{2}'
 MIRRORLIST_ENTRY_FORMAT = "Server = " + MIRROR_URL_FORMAT + "\n"
 
 DEFAULT_CONNECTION_TIMEOUT = 5
+DEFAULT_DOWNLOAD_TIMEOUT = 5
 DEFAULT_CACHE_TIMEOUT = 300
 
 SORT_TYPES = {
@@ -165,9 +167,55 @@ def count_countries(mirrors):
     return countries
 
 
+# ------------------------ download timeout handling ------------------------- #
+
+class DownloadTimeout(Exception):
+    '''
+    Download timeout exception raised by DownloadContext.
+    '''
+
+
+class DownloadTimer():
+    '''
+    Context manager for timing downloads with timeouts.
+    '''
+    def __init__(self, timeout=DEFAULT_DOWNLOAD_TIMEOUT):
+        '''
+        Args:
+            timeout:
+                The download timeout in seconds. The DownloadTimeout exception
+                will be raised in the context after this many seconds.
+        '''
+        self.time = None
+        self.start_time = None
+        self.timeout = timeout
+        self.previous_handler = None
+        self.previous_timer = None
+
+    def raise_timeout(self, signl, frame):
+        '''
+        Raise the DownloadTimeout exception.
+        '''
+        raise DownloadTimeout(f'Download timed out after {self.timeout} second(s).')
+
+    def __enter__(self):
+        self.start_time = time.time()
+        if self.timeout > 0:
+            self.previous_handler = signal.signal(signal.SIGALRM, self.raise_timeout)
+            self.previous_timer = signal.alarm(self.timeout)
+        return self
+
+    def __exit__(self, typ, value, traceback):
+        self.time = time.time() - self.start_time
+        if self.timeout > 0:
+            signal.signal(signal.SIGALRM, self.previous_handler)
+            signal.alarm(self.previous_timer)
+        self.start_time = None
+
+
 # --------------------------------- Sorting ---------------------------------- #
 
-def sort(mirrors, by=None):  # pylint: disable=invalid-name
+def sort(mirrors, by=None, **kwargs):  # pylint: disable=invalid-name
     '''
     Sort mirrors by different criteria.
     '''
@@ -179,7 +227,7 @@ def sort(mirrors, by=None):  # pylint: disable=invalid-name
         mirrors.sort(key=lambda m: m['last_sync'], reverse=True)
 
     elif by == 'rate':
-        rates = rate(mirrors)
+        rates = rate(mirrors, **kwargs)
         mirrors = sorted(mirrors, key=lambda m: rates[m['url']], reverse=True)
 
     else:
@@ -193,7 +241,11 @@ def sort(mirrors, by=None):  # pylint: disable=invalid-name
 
 # ---------------------------------- Rating ---------------------------------- #
 
-def rate_rsync(db_url, connection_timeout=DEFAULT_CONNECTION_TIMEOUT):
+def rate_rsync(
+    db_url,
+    connection_timeout=DEFAULT_CONNECTION_TIMEOUT,
+    download_timeout=DEFAULT_DOWNLOAD_TIMEOUT
+):
     '''
     Download a database via rsync and return the time and rate of the download.
     '''
@@ -205,43 +257,64 @@ def rate_rsync(db_url, connection_timeout=DEFAULT_CONNECTION_TIMEOUT):
     ]
     try:
         with tempfile.TemporaryDirectory() as tmpdir:
-            time_0 = time.time()
-            subprocess.check_call(
-                rsync_cmd + [tmpdir],
-                stdout=subprocess.DEVNULL,
-                stderr=subprocess.DEVNULL
-            )
-            time_delta = time.time() - time_0
+            with DownloadTimer(timeout=download_timeout) as timer:
+                subprocess.check_call(
+                    rsync_cmd + [tmpdir],
+                    stdout=subprocess.DEVNULL,
+                    stderr=subprocess.DEVNULL
+                )
+            time_delta = timer.time
             size = os.path.getsize(
                 os.path.join(tmpdir, os.path.basename(DB_SUBPATH))
             )
             ratio = size / time_delta
             return time_delta, ratio
-    except (subprocess.CalledProcessError, subprocess.TimeoutExpired, FileNotFoundError):
+    except (
+        subprocess.CalledProcessError,
+        subprocess.TimeoutExpired,
+        FileNotFoundError,
+        DownloadTimeout
+    ) as err:
+        logger = get_logger()
+        logger.info('failed to rate rsync download (%s): %s', db_url, err)
         return 0, 0
 
 
-def rate_http(db_url, connection_timeout=DEFAULT_CONNECTION_TIMEOUT):
+def rate_http(
+    db_url,
+    connection_timeout=DEFAULT_CONNECTION_TIMEOUT,
+    download_timeout=DEFAULT_DOWNLOAD_TIMEOUT
+):
     '''
     Download a database via any protocol supported by urlopen and return the time
     and rate of the download.
     '''
     req = urllib.request.Request(url=db_url)
     try:
-        with urllib.request.urlopen(req, None, connection_timeout) as handle:
-            time_0 = time.time()
+        with urllib.request.urlopen(req, None, connection_timeout) as handle, \
+                DownloadTimer(timeout=download_timeout) as timer:
             size = len(handle.read())
-            time_delta = time.time() - time_0
+        time_delta = timer.time
         ratio = size / time_delta
         return time_delta, ratio
-    except (OSError, urllib.error.HTTPError, http.client.HTTPException):
+    except (
+        OSError,
+        urllib.error.HTTPError,
+        http.client.HTTPException,
+        DownloadTimeout
+    ) as err:
+        logger = get_logger()
+        logger.info('failed to rate http(s) download (%s): %s', db_url, err)
         return 0, 0
 
 
-def rate(mirrors, connection_timeout=DEFAULT_CONNECTION_TIMEOUT):
+def rate(
+    mirrors,
+    **kwargs
+):
     '''
     Rate mirrors by timing the download of the community repo's database from
-    each one.
+    each one. Keyword arguments are passed through to rate_rsync and rate_http.
     '''
     # Ensure that mirrors is not a generator so that its length can be determined.
     if not isinstance(mirrors, tuple):
@@ -265,9 +338,9 @@ def rate(mirrors, connection_timeout=DEFAULT_CONNECTION_TIMEOUT):
         scheme = urllib.parse.urlparse(url).scheme
 
         if scheme == 'rsync':
-            time_delta, ratio = rate_rsync(db_url, connection_timeout)
+            time_delta, ratio = rate_rsync(db_url, **kwargs)
         else:
-            time_delta, ratio = rate_http(db_url, connection_timeout)
+            time_delta, ratio = rate_http(db_url, **kwargs)
 
         kibps = ratio / 1024.0
         logger.info(fmt.format(url, kibps, time_delta))
@@ -276,7 +349,7 @@ def rate(mirrors, connection_timeout=DEFAULT_CONNECTION_TIMEOUT):
     return rates
 
 
-# ---------------------------- MirrorStatusError ----------------------------- #
+# -------------------------------- Exceptions -------------------------------- #
 
 class MirrorStatusError(Exception):
     '''
@@ -468,11 +541,13 @@ class MirrorStatus():
     def __init__(
         self,
         connection_timeout=DEFAULT_CONNECTION_TIMEOUT,
+        download_timeout=DEFAULT_DOWNLOAD_TIMEOUT,
         cache_timeout=DEFAULT_CACHE_TIMEOUT,
         min_completion_pct=1.0,
         url=URL
     ):
         self.connection_timeout = connection_timeout
+        self.download_timeout = download_timeout
         self.cache_timeout = cache_timeout
         self.min_completion_pct = min_completion_pct
         self.url = url
@@ -518,21 +593,21 @@ class MirrorStatus():
         msf = MirrorStatusFilter(min_completion_pct=self.min_completion_pct, **kwargs)
         yield from msf.filter_mirrors(mirrors)
 
-    def sort(self, mirrors=None, **kwargs):
+    def sort(self, mirrors, **kwargs):
         '''
         Sort mirrors by various criteria.
         '''
         if mirrors is None:
             mirrors = self.get_mirrors()
+        kwargs.setdefault('connection_timeout', self.connection_timeout)
+        kwargs.setdefault('download_timeout', self.download_timeout)
         yield from sort(mirrors, **kwargs)
 
     def rate(self, mirrors=None, **kwargs):
         '''
         Sort mirrors by download speed.
         '''
-        if mirrors is None:
-            mirrors = self.get_mirrors()
-        yield from sort(mirrors, by='rate', **kwargs)
+        yield from self.sort(mirrors, by='rate', **kwargs)
 
     def get_mirrorlist(self, mirrors=None, include_country=False, cmd=None):
         '''
@@ -601,10 +676,10 @@ def add_arguments(parser):
         help='The number of seconds to wait before a connection times out. Default: %(default)s'
     )
 
-#   parser.add_argument(
-#     '--download-timeout', type=int, metavar='n',
-#     help='The number of seconds to wait before a download times out. The threshold is checked after each chunk is read, so the actual timeout may take longer.'
-#   )
+    parser.add_argument(
+        '--download-timeout', type=int, metavar='n', default=DEFAULT_DOWNLOAD_TIMEOUT,
+        help='The number of seconds to wait before a download times out. Default: %(default)s'
+    )
 
     parser.add_argument(
         '--list-countries', action=ListCountries, nargs=0,
@@ -763,7 +838,7 @@ def process_options(options, mirrorstatus=None, mirrors=None):
     if not mirrorstatus:
         mirrorstatus = MirrorStatus(
             connection_timeout=options.connection_timeout,
-            #       download_timeout=options.download_timeout,
+            download_timeout=options.download_timeout,
             cache_timeout=options.cache_timeout,
             min_completion_pct=(options.completion_percent / 100.),
             url=options.url
diff --git a/setup.py b/setup.py
index 3d5e34a..81f2875 100644
--- a/setup.py
+++ b/setup.py
@@ -5,7 +5,7 @@ import time
 
 setup(
   name='''Reflector''',
-  version=time.strftime('%Y.%m.%d.%H.%M.%S', time.gmtime(1607017235)),
+  version=time.strftime('%Y.%m.%d.%H.%M.%S', time.gmtime(1607320056)),
   description='''A Python 3 module and script to retrieve and filter the latest Pacman mirror list.''',
   author='''Xyne''',
   author_email='''ac xunilhcra enyx, backwards''',