#!/usr/bin/env python
# Copyright 2014 The Chromium Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.
"""A git command for managing a local cache of git repositories."""
from __future__ import print_function
import errno
import logging
import optparse
import os
import re
import tempfile
import threading
import time
import subprocess
import sys
import urlparse
import zipfile
from download_from_google_storage import Gsutil
import gclient_utils
import subcommand
# Analogous to gc.autopacklimit git config.
GC_AUTOPACKLIMIT = 50
GIT_CACHE_CORRUPT_MESSAGE = 'WARNING: The Git cache is corrupt.'
try:
# pylint: disable=E0602
WinErr = WindowsError
except NameError:
class WinErr(Exception):
pass
class LockError(Exception):
pass
class RefsHeadsFailedToFetch(Exception):
pass
class Lockfile(object):
"""Class to represent a cross-platform process-specific lockfile."""
def __init__(self, path, timeout=0):
self.path = os.path.abspath(path)
self.timeout = timeout
self.lockfile = self.path + ".lock"
self.pid = os.getpid()
def _read_pid(self):
"""Read the pid stored in the lockfile.
Note: This method is potentially racy. By the time it returns the lockfile
may have been unlocked, removed, or stolen by some other process.
"""
try:
with open(self.lockfile, 'r') as f:
pid = int(f.readline().strip())
except (IOError, ValueError):
pid = None
return pid
def _make_lockfile(self):
"""Safely creates a lockfile containing the current pid."""
open_flags = (os.O_CREAT | os.O_EXCL | os.O_WRONLY)
fd = os.open(self.lockfile, open_flags, 0o644)
f = os.fdopen(fd, 'w')
print(self.pid, file=f)
f.close()
def _remove_lockfile(self):
"""Delete the lockfile. Complains (implicitly) if it doesn't exist.
See gclient_utils.py:rmtree docstring for more explanation on the
windows case.
"""
if sys.platform == 'win32':
lockfile = os.path.normcase(self.lockfile)
for _ in xrange(3):
exitcode = subprocess.call(['cmd.exe', '/c',
'del', '/f', '/q', lockfile])
if exitcode == 0:
return
time.sleep(3)
raise LockError('Failed to remove lock: %s' % lockfile)
else:
os.remove(self.lockfile)
def lock(self):
"""Acquire the lock.
This will block with a deadline of self.timeout seconds.
"""
elapsed = 0
while True:
try:
self._make_lockfile()
return
except OSError as e:
if elapsed < self.timeout:
sleep_time = max(10, min(3, self.timeout - elapsed))
logging.info('Could not create git cache lockfile; '
'will retry after sleep(%d).', sleep_time);
elapsed += sleep_time
time.sleep(sleep_time)
continue
if e.errno == errno.EEXIST:
raise LockError("%s is already locked" % self.path)
else:
raise LockError("Failed to create %s (err %s)" % (self.path, e.errno))
def unlock(self):
"""Release the lock."""
try:
if not self.is_locked():
raise LockError("%s is not locked" % self.path)
if not self.i_am_locking():
raise LockError("%s is locked, but not by me" % self.path)
self._remove_lockfile()
except WinErr:
# Windows is unreliable when it comes to file locking. YMMV.
pass
def break_lock(self):
"""Remove the lock, even if it was created by someone else."""
try:
self._remove_lockfile()
return True
except OSError as exc:
if exc.errno == errno.ENOENT:
return False
else:
raise
def is_locked(self):
"""Test if the file is locked by anyone.
Note: This method is potentially racy. By the time it returns the lockfile
may have been unlocked, removed, or stolen by some other process.
"""
return os.path.exists(self.lockfile)
def i_am_locking(self):
"""Test if the file is locked by this process."""
return self.is_locked() and self.pid == self._read_pid()
class Mirror(object):
git_exe = 'git.bat' if sys.platform.startswith('win') else 'git'
gsutil_exe = os.path.join(
os.path.dirname(os.path.abspath(__file__)), 'gsutil.py')
cachepath_lock = threading.Lock()
@staticmethod
def parse_fetch_spec(spec):
"""Parses and canonicalizes a fetch spec.
Returns (fetchspec, value_regex), where value_regex can be used
with 'git config --replace-all'.
"""
parts = spec.split(':', 1)
src = parts[0].lstrip('+').rstrip('/')
if not src.startswith('refs/'):
src = 'refs/heads/%s' % src
dest = parts[1].rstrip('/') if len(parts) > 1 else src
regex = r'\+%s:.*' % src.replace('*', r'\*')
return ('+%s:%s' % (src, dest), regex)
def __init__(self, url, refs=None, print_func=None):
self.url = url
self.fetch_specs = set([self.parse_fetch_spec(ref) for ref in (refs or [])])
self.basedir = self.UrlToCacheDir(url)
self.mirror_path = os.path.join(self.GetCachePath(), self.basedir)
if print_func:
self.print = self.print_without_file
self.print_func = print_func
else:
self.print = print
def print_without_file(self, message, **kwargs):
self.print_func(message)
@property
def bootstrap_bucket(self):
if 'chrome-internal' in self.url:
return 'chrome-git-cache'
else:
return 'chromium-git-cache'
@classmethod
def FromPath(cls, path):
return cls(cls.CacheDirToUrl(path))
@staticmethod
def UrlToCacheDir(url):
"""Convert a git url to a normalized form for the cache dir path."""
parsed = urlparse.urlparse(url)
norm_url = parsed.netloc + parsed.path
if norm_url.endswith('.git'):
norm_url = norm_url[:-len('.git')]
return norm_url.replace('-', '--').replace('/', '-').lower()
@staticmethod
def CacheDirToUrl(path):
"""Convert a cache dir path to its corresponding url."""
netpath = re.sub(r'\b-\b', '/', os.path.basename(path)).replace('--', '-')
return 'https://%s' % netpath
@classmethod
def SetCachePath(cls, cachepath):
with cls.cachepath_lock:
setattr(cls, 'cachepath', cachepath)
@classmethod
def GetCachePath(cls):
with cls.cachepath_lock:
if not hasattr(cls, 'cachepath'):
try:
cachepath = subprocess.check_output(
[cls.git_exe, 'config', '--global', 'cache.cachepath']).strip()
except subprocess.CalledProcessError:
cachepath = None
if not cachepath:
raise RuntimeError(
'No global cache.cachepath git configuration found.')
setattr(cls, 'cachepath', cachepath)
return getattr(cls, 'cachepath')
def RunGit(self, cmd, **kwargs):
"""Run git in a subprocess."""
cwd = kwargs.setdefault('cwd', self.mirror_path)
kwargs.setdefault('print_stdout', False)
kwargs.setdefault('filter_fn', self.print)
env = kwargs.get('env') or kwargs.setdefault('env', os.environ.copy())
env.setdefault('GIT_ASKPASS', 'true')
env.setdefault('SSH_ASKPASS', 'true')
self.print('running "git %s" in "%s"' % (' '.join(cmd), cwd))
gclient_utils.CheckCallAndFilter([self.git_exe] + cmd, **kwargs)
def config(self, cwd=None):
if cwd is None:
cwd = self.mirror_path
# Don't run git-gc in a daemon. Bad things can happen if it gets killed.
self.RunGit(['config', 'gc.autodetach', '0'], cwd=cwd)
# Don't combine pack files into one big pack file. It's really slow for
# repositories, and there's no way to track progress and make sure it's
# not stuck.
self.RunGit(['config', 'gc.autopacklimit', '0'], cwd=cwd)
# Allocate more RAM for cache-ing delta chains, for better performance
# of "Resolving deltas".
self.RunGit(['config', 'core.deltaBaseCacheLimit',
gclient_utils.DefaultDeltaBaseCacheLimit()], cwd=cwd)
self.RunGit(['config', 'remote.origin.url', self.url], cwd=cwd)
self.RunGit(['config', '--replace-all', 'remote.origin.fetch',
'+refs/heads/*:refs/heads/*', r'\+refs/heads/\*:.*'], cwd=cwd)
for spec, value_regex in self.fetch_specs:
self.RunGit(
['config', '--replace-all', 'remote.origin.fetch', spec, value_regex],
cwd=cwd)
def bootstrap_repo(self, directory):
"""Bootstrap the repo from Google Stroage if possible.
More apt-ly named bootstrap_repo_from_cloud_if_possible_else_do_nothing().
"""
python_fallback = False
if (sys.platform.startswith('win') and
not gclient_utils.FindExecutable('7z')):
python_fallback = True
elif sys.platform.startswith('darwin'):
# The OSX version of unzip doesn't support zip64.
python_fallback = True
elif not gclient_utils.FindExecutable('unzip'):
python_fallback = True
gs_folder = 'gs://%s/%s' % (self.bootstrap_bucket, self.basedir)
gsutil = Gsutil(self.gsutil_exe, boto_path=None)
# Get the most recent version of the zipfile.
_, ls_out, _ = gsutil.check_call('ls', gs_folder)
ls_out_sorted = sorted(ls_out.splitlines())
if not ls_out_sorted:
# This repo is not on Google Storage.
return False
latest_checkout = ls_out_sorted[-1]
# Download zip file to a temporary directory.
try:
tempdir = tempfile.mkdtemp(prefix='_cache_tmp', dir=self.GetCachePath())
self.print('Downloading %s' % latest_checkout)
code = gsutil.call('cp', latest_checkout, tempdir)
if code:
return False
filename = os.path.join(tempdir, latest_checkout.split('/')[-1])
# Unpack the file with 7z on Windows, unzip on linux, or fallback.
if not python_fallback:
if sys.platform.startswith('win'):
cmd = ['7z', 'x', '-o%s' % directory, '-tzip', filename]
else:
cmd = ['unzip', filename, '-d', directory]
retcode = subprocess.call(cmd)
else:
try:
with zipfile.ZipFile(filename, 'r') as f:
f.printdir()
f.extractall(directory)
except Exception as e:
self.print('Encountered error: %s' % str(e), file=sys.stderr)
retcode = 1
else:
retcode = 0
finally:
# Clean up the downloaded zipfile.
gclient_utils.rm_file_or_tree(tempdir)
if retcode:
self.print(
'Extracting bootstrap zipfile %s failed.\n'
'Resuming normal operations.' % filename)
return False
return True
def exists(self):
return os.path.isfile(os.path.join(self.mirror_path, 'config'))
def _preserve_fetchspec(self):
"""Read and preserve remote.origin.fetch from an existing mirror.
This modifies self.fetch_specs.
"""
if not self.exists():
return
try:
config_fetchspecs = subprocess.check_output(
[self.git_exe, 'config', '--get-all', 'remote.origin.fetch'],
cwd=self.mirror_path)
for fetchspec in config_fetchspecs.splitlines():
self.fetch_specs.add(self.parse_fetch_spec(fetchspec))
except subprocess.CalledProcessError:
logging.warn('Tried and failed to preserve remote.origin.fetch from the '
'existing cache directory. You may need to manually edit '
'%s and "git cache fetch" again.'
% os.path.join(self.mirror_path, 'config'))
def _ensure_bootstrapped(self, depth, bootstrap, force=False):
tempdir = None
pack_dir = os.path.join(self.mirror_path, 'objects', 'pack')
pack_files = []
if os.path.isdir(pack_dir):
pack_files = [f for f in os.listdir(pack_dir) if f.endswith('.pack')]
should_bootstrap = (force or
not self.exists() or
len(pack_files) > GC_AUTOPACKLIMIT)
if should_bootstrap:
if self.exists():
# Re-bootstrapping an existing mirror; preserve existing fetch spec.
self._preserve_fetchspec()
tempdir = tempfile.mkdtemp(
prefix='_cache_tmp', suffix=self.basedir, dir=self.GetCachePath())
bootstrapped = not depth and bootstrap and self.bootstrap_repo(tempdir)
if bootstrapped:
# Bootstrap succeeded; delete previous cache, if any.
gclient_utils.rmtree(self.mirror_path)
elif not self.exists():
# Bootstrap failed, no previous cache; start with a bare git dir.
self.RunGit(['init', '--bare'], cwd=tempdir)
else:
# Bootstrap failed, previous cache exists; warn and continue.
logging.warn(
'Git cache has a lot of pack files (%d). Tried to re-bootstrap '
'but failed. Continuing with non-optimized repository.'
% len(pack_files))
gclient_utils.rmtree(tempdir)
tempdir = None
else:
if depth and os.path.exists(os.path.join(self.mirror_path, 'shallow')):
logging.warn(
'Shallow fetch requested, but repo cache already exists.')
return tempdir
def _fetch(self, rundir, verbose, depth):
self.config(rundir)
v = []
d = []
if verbose:
v = ['-v', '--progress']
if depth:
d = ['--depth', str(depth)]
fetch_cmd = ['fetch'] + v + d + ['origin']
fetch_specs = subprocess.check_output(
[self.git_exe, 'config', '--get-all', 'remote.origin.fetch'],
cwd=rundir).strip().splitlines()
for spec in fetch_specs:
try:
self.print('Fetching %s' % spec)
self.RunGit(fetch_cmd + [spec], cwd=rundir, retry=True)
except subprocess.CalledProcessError:
if spec == '+refs/heads/*:refs/heads/*':
raise RefsHeadsFailedToFetch
logging.warn('Fetch of %s failed' % spec)
def populate(self, depth=None, shallow=False, bootstrap=False,
verbose=False, ignore_lock=False, lock_timeout=0):
assert self.GetCachePath()
if shallow and not depth:
depth = 10000
gclient_utils.safe_makedirs(self.GetCachePath())
lockfile = Lockfile(self.mirror_path, lock_timeout)
if not ignore_lock:
lockfile.lock()
tempdir = None
try:
tempdir = self._ensure_bootstrapped(depth, bootstrap)
rundir = tempdir or self.mirror_path
self._fetch(rundir, verbose, depth)
except RefsHeadsFailedToFetch:
# This is a major failure, we need to clean and force a bootstrap.
gclient_utils.rmtree(rundir)
self.print(GIT_CACHE_CORRUPT_MESSAGE)
tempdir = self._ensure_bootstrapped(depth, bootstrap, force=True)
assert tempdir
self._fetch(tempdir or self.mirror_path, verbose, depth)
finally:
if tempdir:
try:
if os.path.exists(self.mirror_path):
gclient_utils.rmtree(self.mirror_path)
os.rename(tempdir, self.mirror_path)
except OSError as e:
# This is somehow racy on Windows.
# Catching OSError because WindowsError isn't portable and
# pylint complains.
self.print('Error moving %s to %s: %s' % (tempdir, self.mirror_path,
str(e)))
if not ignore_lock:
lockfile.unlock()
def update_bootstrap(self, prune=False):
# The files are named <git number>.zip
gen_number = subprocess.check_output(
[self.git_exe, 'number', 'master'], cwd=self.mirror_path).strip()
# Run Garbage Collect to compress packfile.
self.RunGit(['gc', '--prune=all'])
# Creating a temp file and then deleting it ensures we can use this name.
_, tmp_zipfile = tempfile.mkstemp(suffix='.zip')
os.remove(tmp_zipfile)
subprocess.call(['zip', '-r', tmp_zipfile, '.'], cwd=self.mirror_path)
gsutil = Gsutil(path=self.gsutil_exe, boto_path=None)
gs_folder = 'gs://%s/%s' % (self.bootstrap_bucket, self.basedir)
dest_name = '%s/%s.zip' % (gs_folder, gen_number)
gsutil.call('cp', tmp_zipfile, dest_name)
os.remove(tmp_zipfile)
# Remove all other files in the same directory.
if prune:
_, ls_out, _ = gsutil.check_call('ls', gs_folder)
for filename in ls_out.splitlines():
if filename == dest_name:
continue
gsutil.call('rm', filename)
@staticmethod
def DeleteTmpPackFiles(path):
pack_dir = os.path.join(path, 'objects', 'pack')
if not os.path.isdir(pack_dir):
return
pack_files = [f for f in os.listdir(pack_dir) if
f.startswith('.tmp-') or f.startswith('tmp_pack_')]
for f in pack_files:
f = os.path.join(pack_dir, f)
try:
os.remove(f)
logging.warn('Deleted stale temporary pack file %s' % f)
except OSError:
logging.warn('Unable to delete temporary pack file %s' % f)
@classmethod
def BreakLocks(cls, path):
did_unlock = False
lf = Lockfile(path)
if lf.break_lock():
did_unlock = True
# Look for lock files that might have been left behind by an interrupted
# git process.
lf = os.path.join(path, 'config.lock')
if os.path.exists(lf):
os.remove(lf)
did_unlock = True
cls.DeleteTmpPackFiles(path)
return did_unlock
def unlock(self):
return self.BreakLocks(self.mirror_path)
@classmethod
def UnlockAll(cls):
cachepath = cls.GetCachePath()
if not cachepath:
return
dirlist = os.listdir(cachepath)
repo_dirs = set([os.path.join(cachepath, path) for path in dirlist
if os.path.isdir(os.path.join(cachepath, path))])
for dirent in dirlist:
if dirent.startswith('_cache_tmp') or dirent.startswith('tmp'):
gclient_utils.rm_file_or_tree(os.path.join(cachepath, dirent))
elif (dirent.endswith('.lock') and
os.path.isfile(os.path.join(cachepath, dirent))):
repo_dirs.add(os.path.join(cachepath, dirent[:-5]))
unlocked_repos = []
for repo_dir in repo_dirs:
if cls.BreakLocks(repo_dir):
unlocked_repos.append(repo_dir)
return unlocked_repos
@subcommand.usage('[url of repo to check for caching]')
def CMDexists(parser, args):
"""Check to see if there already is a cache of the given repo."""
_, args = parser.parse_args(args)
if not len(args) == 1:
parser.error('git cache exists only takes exactly one repo url.')
url = args[0]
mirror = Mirror(url)
if mirror.exists():
print(mirror.mirror_path)
return 0
return 1
@subcommand.usage('[url of repo to create a bootstrap zip file]')
def CMDupdate_bootstrap(parser, args):
"""Create and uploads a bootstrap tarball."""
# Lets just assert we can't do this on Windows.
if sys.platform.startswith('win'):
print('Sorry, update bootstrap will not work on Windows.', file=sys.stderr)
return 1
parser.add_option('--prune', action='store_true',
help='Prune all other cached zipballs of the same repo.')
# First, we need to ensure the cache is populated.
populate_args = args[:]
populate_args.append('--no-bootstrap')
CMDpopulate(parser, populate_args)
# Get the repo directory.
options, args = parser.parse_args(args)
url = args[0]
mirror = Mirror(url)
mirror.update_bootstrap(options.prune)
return 0
@subcommand.usage('[url of repo to add to or update in cache]')
def CMDpopulate(parser, args):
"""Ensure that the cache has all up-to-date objects for the given repo."""
parser.add_option('--depth', type='int',
help='Only cache DEPTH commits of history')
parser.add_option('--shallow', '-s', action='store_true',
help='Only cache 10000 commits of history')
parser.add_option('--ref', action='append',
help='Specify additional refs to be fetched')
parser.add_option('--no_bootstrap', '--no-bootstrap',
action='store_true',
help='Don\'t bootstrap from Google Storage')
parser.add_option('--ignore_locks', '--ignore-locks',
action='store_true',
help='Don\'t try to lock repository')
options, args = parser.parse_args(args)
if not len(args) == 1:
parser.error('git cache populate only takes exactly one repo url.')
url = args[0]
mirror = Mirror(url, refs=options.ref)
kwargs = {
'verbose': options.verbose,
'shallow': options.shallow,
'bootstrap': not options.no_bootstrap,
'ignore_lock': options.ignore_locks,
'lock_timeout': options.timeout,
}
if options.depth:
kwargs['depth'] = options.depth
mirror.populate(**kwargs)
@subcommand.usage('Fetch new commits into cache and current checkout')
def CMDfetch(parser, args):
"""Update mirror, and fetch in cwd."""
parser.add_option('--all', action='store_true', help='Fetch all remotes')
parser.add_option('--no_bootstrap', '--no-bootstrap',
action='store_true',
help='Don\'t (re)bootstrap from Google Storage')
options, args = parser.parse_args(args)
# Figure out which remotes to fetch. This mimics the behavior of regular
# 'git fetch'. Note that in the case of "stacked" or "pipelined" branches,
# this will NOT try to traverse up the branching structure to find the
# ultimate remote to update.
remotes = []
if options.all:
assert not args, 'fatal: fetch --all does not take a repository argument'
remotes = subprocess.check_output([Mirror.git_exe, 'remote']).splitlines()
elif args:
remotes = args
else:
current_branch = subprocess.check_output(
[Mirror.git_exe, 'rev-parse', '--abbrev-ref', 'HEAD']).strip()
if current_branch != 'HEAD':
upstream = subprocess.check_output(
[Mirror.git_exe, 'config', 'branch.%s.remote' % current_branch]
).strip()
if upstream and upstream != '.':
remotes = [upstream]
if not remotes:
remotes = ['origin']
cachepath = Mirror.GetCachePath()
git_dir = os.path.abspath(subprocess.check_output(
[Mirror.git_exe, 'rev-parse', '--git-dir']))
git_dir = os.path.abspath(git_dir)
if git_dir.startswith(cachepath):
mirror = Mirror.FromPath(git_dir)
mirror.populate(
bootstrap=not options.no_bootstrap, lock_timeout=options.timeout)
return 0
for remote in remotes:
remote_url = subprocess.check_output(
[Mirror.git_exe, 'config', 'remote.%s.url' % remote]).strip()
if remote_url.startswith(cachepath):
mirror = Mirror.FromPath(remote_url)
mirror.print = lambda *args: None
print('Updating git cache...')
mirror.populate(
bootstrap=not options.no_bootstrap, lock_timeout=options.timeout)
subprocess.check_call([Mirror.git_exe, 'fetch', remote])
return 0
@subcommand.usage('[url of repo to unlock, or -a|--all]')
def CMDunlock(parser, args):
"""Unlock one or all repos if their lock files are still around."""
parser.add_option('--force', '-f', action='store_true',
help='Actually perform the action')
parser.add_option('--all', '-a', action='store_true',
help='Unlock all repository caches')
options, args = parser.parse_args(args)
if len(args) > 1 or (len(args) == 0 and not options.all):
parser.error('git cache unlock takes exactly one repo url, or --all')
if not options.force:
cachepath = Mirror.GetCachePath()
lockfiles = [os.path.join(cachepath, path)
for path in os.listdir(cachepath)
if path.endswith('.lock') and os.path.isfile(path)]
parser.error('git cache unlock requires -f|--force to do anything. '
'Refusing to unlock the following repo caches: '
', '.join(lockfiles))
unlocked_repos = []
if options.all:
unlocked_repos.extend(Mirror.UnlockAll())
else:
m = Mirror(args[0])
if m.unlock():
unlocked_repos.append(m.mirror_path)
if unlocked_repos:
logging.info('Broke locks on these caches:\n %s' % '\n '.join(
unlocked_repos))
class OptionParser(optparse.OptionParser):
"""Wrapper class for OptionParser to handle global options."""
def __init__(self, *args, **kwargs):
optparse.OptionParser.__init__(self, *args, prog='git cache', **kwargs)
self.add_option('-c', '--cache-dir',
help='Path to the directory containing the cache')
self.add_option('-v', '--verbose', action='count', default=1,
help='Increase verbosity (can be passed multiple times)')
self.add_option('-q', '--quiet', action='store_true',
help='Suppress all extraneous output')
self.add_option('--timeout', type='int', default=0,
help='Timeout for acquiring cache lock, in seconds')
def parse_args(self, args=None, values=None):
options, args = optparse.OptionParser.parse_args(self, args, values)
if options.quiet:
options.verbose = 0
levels = [logging.ERROR, logging.WARNING, logging.INFO, logging.DEBUG]
logging.basicConfig(level=levels[min(options.verbose, len(levels) - 1)])
try:
global_cache_dir = Mirror.GetCachePath()
except RuntimeError:
global_cache_dir = None
if options.cache_dir:
if global_cache_dir and (
os.path.abspath(options.cache_dir) !=
os.path.abspath(global_cache_dir)):
logging.warn('Overriding globally-configured cache directory.')
Mirror.SetCachePath(options.cache_dir)
return options, args
def main(argv):
dispatcher = subcommand.CommandDispatcher(__name__)
return dispatcher.execute(OptionParser(), argv)
if __name__ == '__main__':
try:
sys.exit(main(sys.argv[1:]))
except KeyboardInterrupt:
sys.stderr.write('interrupted\n')
sys.exit(1)