virt-manager/virtinst/urlfetcher.py

387 lines
11 KiB
Python

#
# Copyright 2006-2007, 2013 Red Hat, Inc.
# Daniel P. Berrange <berrange@redhat.com>
#
# This work is licensed under the GNU GPLv2 or later.
# See the COPYING file in the top-level directory.
import ftplib
import io
import logging
import os
import subprocess
import tempfile
import urllib
import requests
#########################################################################
# Backends for the various URL types we support (http, ftp, nfs, local) #
#########################################################################
class _URLFetcher(object):
"""
This is a generic base class for fetching/extracting files from
a media source, such as CD ISO, NFS server, or HTTP/FTP server
"""
_block_size = 16384
def __init__(self, location, scratchdir, meter):
self.location = location
self.scratchdir = scratchdir
self.meter = meter
self._srcdir = None
logging.debug("Using scratchdir=%s", scratchdir)
####################
# Internal helpers #
####################
def _make_full_url(self, filename):
"""
Generate a full fetchable URL from the passed filename, which
is relative to the self.location
"""
ret = self._srcdir or self.location
if not filename:
return ret
if not ret.endswith("/"):
ret += "/"
return ret + filename
def _grabURL(self, filename, fileobj):
"""
Download the filename from self.location, and write contents to
fileobj
"""
url = self._make_full_url(filename)
try:
urlobj, size = self._grabber(url)
except Exception as e:
raise ValueError(_("Couldn't acquire file %s: %s") %
(url, str(e)))
logging.debug("Fetching URI: %s", url)
self.meter.start(
text=_("Retrieving file %s...") % os.path.basename(filename),
size=size)
total = self._write(urlobj, fileobj)
self.meter.end(total)
def _write(self, urlobj, fileobj):
"""
Write the contents of urlobj to python file like object fileobj
"""
total = 0
while 1:
buff = urlobj.read(self._block_size)
if not buff:
break
fileobj.write(buff)
total += len(buff)
self.meter.update(total)
return total
def _grabber(self, url):
"""
Returns the urlobj, size for the passed URL. urlobj is whatever
data needs to be passed to self._write
"""
raise NotImplementedError("must be implemented in subclass")
##############
# Public API #
##############
def prepareLocation(self):
"""
Perform any necessary setup
"""
pass
def cleanupLocation(self):
"""
Perform any necessary cleanup
"""
pass
def can_access(self):
"""
Return True if the location URL seems to be valid
"""
return True
def _hasFile(self, url):
raise NotImplementedError("Must be implemented in subclass")
def hasFile(self, filename):
"""
Return True if self.location has the passed filename
"""
url = self._make_full_url(filename)
ret = self._hasFile(url)
logging.debug("hasFile(%s) returning %s", url, ret)
return ret
def acquireFile(self, filename):
"""
Grab the passed filename from self.location and save it to
a temporary file, returning the temp filename
"""
prefix = "virtinst-" + os.path.basename(filename) + "."
# pylint: disable=redefined-variable-type
if "VIRTINST_TEST_SUITE" in os.environ:
fn = os.path.join("/tmp", prefix)
fileobj = open(fn, "wb")
else:
fileobj = tempfile.NamedTemporaryFile(
dir=self.scratchdir, prefix=prefix, delete=False)
fn = fileobj.name
self._grabURL(filename, fileobj)
logging.debug("Saved file to %s", fn)
return fn
def acquireFileContent(self, filename):
"""
Grab the passed filename from self.location and return it as a string
"""
fileobj = io.BytesIO()
self._grabURL(filename, fileobj)
return fileobj.getvalue().decode("utf-8")
class _HTTPURLFetcher(_URLFetcher):
_session = None
def prepareLocation(self):
self._session = requests.Session()
def cleanupLocation(self):
if self._session:
try:
self._session.close()
except Exception:
logging.debug("Error closing requests.session", exc_info=True)
self._session = None
def can_access(self):
return self.hasFile("")
def _hasFile(self, url):
"""
We just do a HEAD request to see if the file exists
"""
try:
response = self._session.head(url, allow_redirects=True)
response.raise_for_status()
except Exception as e:
logging.debug("HTTP hasFile request failed: %s", str(e))
return False
return True
def _grabber(self, url):
"""
Use requests for this
"""
response = self._session.get(url, stream=True)
response.raise_for_status()
try:
size = int(response.headers.get('content-length'))
except Exception:
size = None
return response, size
def _write(self, urlobj, fileobj):
"""
The requests object doesn't have a file-like read() option, so
we need to implemente it ourselves
"""
total = 0
for data in urlobj.iter_content(chunk_size=self._block_size):
fileobj.write(data)
total += len(data)
self.meter.update(total)
return total
class _FTPURLFetcher(_URLFetcher):
_ftp = None
def prepareLocation(self):
if self._ftp:
return
try:
parsed = urllib.parse.urlparse(self.location)
self._ftp = ftplib.FTP()
username = urllib.parse.unquote(parsed.username or '')
password = urllib.parse.unquote(parsed.password or '')
self._ftp.connect(parsed.hostname, parsed.port or 0)
self._ftp.login(username, password)
# Force binary mode
self._ftp.voidcmd("TYPE I")
except Exception as e:
raise ValueError(_("Opening URL %s failed: %s.") %
(self.location, str(e)))
def _grabber(self, url):
"""
Use urllib and ftplib to grab the file
"""
request = urllib.request.Request(url)
urlobj = urllib.request.urlopen(request)
size = self._ftp.size(urllib.parse.urlparse(url)[2])
return urlobj, size
def cleanupLocation(self):
if not self._ftp:
return
try:
self._ftp.quit()
except Exception:
logging.debug("Error quitting ftp connection", exc_info=True)
self._ftp = None
def _hasFile(self, url):
path = urllib.parse.urlparse(url)[2]
try:
try:
# If it's a file
self._ftp.size(path)
except ftplib.all_errors:
# If it's a dir
self._ftp.cwd(path)
except ftplib.all_errors as e:
logging.debug("FTP hasFile: couldn't access %s: %s",
url, str(e))
return False
return True
class _LocalURLFetcher(_URLFetcher):
"""
For grabbing files from a local directory
"""
def _hasFile(self, url):
return os.path.exists(url)
def _grabber(self, url):
urlobj = open(url, "rb")
size = os.path.getsize(url)
return urlobj, size
class _MountedURLFetcher(_LocalURLFetcher):
"""
Fetcher capable of extracting files from a NFS server
or loopback mounted file, or local CDROM device
"""
_in_test_suite = bool("VIRTINST_TEST_SUITE" in os.environ)
_mounted = False
def prepareLocation(self):
if self._mounted:
return
if self._in_test_suite:
self._srcdir = os.environ["VIRTINST_TEST_URL_DIR"]
else:
self._srcdir = tempfile.mkdtemp(prefix="virtinstmnt.",
dir=self.scratchdir)
mountcmd = "/bin/mount"
logging.debug("Preparing mount at %s", self._srcdir)
cmd = [mountcmd, "-o", "ro", self.location[4:], self._srcdir]
logging.debug("mount cmd: %s", cmd)
if not self._in_test_suite:
ret = subprocess.call(cmd)
if ret != 0:
self.cleanupLocation()
raise ValueError(_("Mounting location '%s' failed") %
(self.location))
self._mounted = True
def cleanupLocation(self):
if not self._mounted:
return
logging.debug("Cleaning up mount at %s", self._srcdir)
try:
if not self._in_test_suite:
cmd = ["/bin/umount", self._srcdir]
subprocess.call(cmd)
try:
os.rmdir(self._srcdir)
except Exception:
pass
finally:
self._mounted = False
class _ISOURLFetcher(_URLFetcher):
_cache_file_list = None
def _make_full_url(self, filename):
return "/" + filename
def _grabber(self, url):
"""
Use isoinfo to grab the file
"""
if not self._hasFile(url):
raise RuntimeError("isoinfo didn't find file=%s" % url)
cmd = ["isoinfo", "-J", "-i", self.location, "-x", url]
logging.debug("Running isoinfo: %s", cmd)
output = subprocess.check_output(cmd)
return io.BytesIO(output), len(output)
def _hasFile(self, url):
"""
Use isoinfo to list and search for the file
"""
if not self._cache_file_list:
cmd = ["isoinfo", "-J", "-i", self.location, "-f"]
logging.debug("Running isoinfo: %s", cmd)
output = subprocess.check_output(cmd)
self._cache_file_list = output.splitlines(False)
return url.encode("ascii") in self._cache_file_list
def fetcherForURI(uri, *args, **kwargs):
if uri.startswith("http://") or uri.startswith("https://"):
fclass = _HTTPURLFetcher
elif uri.startswith("ftp://"):
fclass = _FTPURLFetcher
elif uri.startswith("nfs:"):
fclass = _MountedURLFetcher
elif os.path.isdir(uri):
# Pointing to a local tree
fclass = _LocalURLFetcher
else:
# Pointing to a path (e.g. iso), or a block device (e.g. /dev/cdrom)
fclass = _ISOURLFetcher
return fclass(uri, *args, **kwargs)