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# Copyright (C) 2012-2015 Codethink Limited
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; version 2 of the License.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License along
# with this program; if not, write to the Free Software Foundation, Inc.,
# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
import cliapp
import logging
import shutil
import urllib
import urllib2
import urlparse
class HeadRequest(urllib2.Request): # pragma: no cover
def get_method(self):
return 'HEAD'
class GetError(cliapp.AppException):
def __init__(self, cache, filename, error):
cliapp.AppException.__init__(
self, 'Failed to get the file %s from the artifact cache %s: %s' %
(filename, cache, error))
class RemoteArtifactCache(object):
def __init__(self, server_url):
self.server_url = server_url
def has(self, artifact):
return self._has_file(artifact.basename())
def has_artifact_metadata(self, artifact, name):
return self._has_file(artifact.metadata_basename(name))
def has_source_metadata(self, source, cachekey, name):
filename = '%s.%s' % (cachekey, name)
return self._has_file(filename)
def _has_file(self, filename): # pragma: no cover
url = self._request_url(filename)
logging.debug('RemoteArtifactCache._has_file: url=%s' % url)
request = HeadRequest(url)
try:
urllib2.urlopen(request)
return True
except (urllib2.HTTPError, urllib2.URLError):
return False
def _request_url(self, filename): # pragma: no cover
server_url = self.server_url
if not server_url.endswith('/'):
server_url += '/'
return urlparse.urljoin(
server_url, '/1.0/artifacts?filename=%s' %
urllib.quote(filename))
def __str__(self): # pragma: no cover
return self.server_url
def _fetch_file(self, remote_filename, local_file):
remote_url = self._request_url(remote_filename)
logging.debug('RemoteArtifactCache._fetch_file: url=%s' % remote_url)
try:
remote_file = urllib2.urlopen(remote_url)
shutil.copyfileobj(remote_file, local_file)
except (urllib.HTTPError, urllib.URLError) as e:
logging.debug(str(e))
raise GetError(self, remote_filename, e)
def _fetch_files(self, to_fetch):
'''Fetch a set of files atomically.
If an error occurs during the transfer of any files, all downloaded
data is deleted, to reduce the chances of having artifacts in the local
cache that are missing their metadata, and so on.
This assumes that the morphlib.savefile module is used so the file
handles passed in to_fetch have a .abort() method.
'''
try:
for remote_filename, local_file in to_fetch:
self._fetch_file(remote_filename, local_file)
except BaseException:
for _, local_file in to_fetch:
local_file.abort()
raise
else:
for _, local_file in to_fetch:
local_file.close()
def get_artifact(self, artifact, lac, status_cb=None):
'''Ensure an artifact is available in the local artifact cache.'''
to_fetch = []
if not lac.has(artifact):
to_fetch.append(
(artifact.basename(), lac.put(artifact)))
if artifact.source.morphology.needs_artifact_metadata_cached:
if not lac.has_artifact_metadata(artifact, 'meta'):
to_fetch.append((
artifact.metadata_basename(artifact, 'meta'),
lac.put_artifact_metadata(artifact, 'meta')))
if len(to_fetch) > 0:
if status_cb:
status_cb(
msg='Fetching to local cache: artifact %(name)s',
name=artifact.name)
self._fetch_files(to_fetch)
def get_artifacts(self, artifacts, lac, status_cb=None):
'''Ensure multiple artifacts are available in the local cache.'''
# FIXME: Running the downloads in parallel may give a speed boost, as
# many of these are small files.
for artifact in artifacts:
self.get_artifact(artifact, lac, status_cb=status_cb)
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