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#!/usr/bin/env python3
'''
clone_fs.py - this file is part of S3QL.
Clone an S3QL file system from one backend into another, without
recompressing or reencrypting.
Copyright © 2008 Nikolaus Rath <Nikolaus@rath.org>
This work can be distributed under the terms of the GNU GPLv3.
'''
import os
import sys
import tempfile
import time
from queue import Queue, Full as QueueFull
# We are running from the S3QL source directory, make sure
# that we use modules from this directory
basedir = os.path.abspath(os.path.join(os.path.dirname(sys.argv[0]), '..'))
if (os.path.exists(os.path.join(basedir, 'setup.py')) and
os.path.exists(os.path.join(basedir, 'src', 's3ql', '__init__.py'))):
sys.path = [os.path.join(basedir, 'src')] + sys.path
from s3ql.logging import logging, setup_logging, QuietError
from s3ql.common import get_backend_factory, AsyncFn, handle_on_return
from s3ql.backends.common import DanglingStorageURLError
from s3ql import BUFSIZE
from s3ql.parse_args import ArgumentParser, storage_url_type
log = logging.getLogger(__name__)
def parse_args(args):
'''Parse command line'''
parser = ArgumentParser(
description='Clone an S3QL file system.')
parser.add_authfile()
parser.add_quiet()
parser.add_debug()
parser.add_backend_options()
parser.add_version()
parser.add_argument("src_storage_url", metavar='<source-storage-url>',
type=storage_url_type,
help='Storage URL of the source backend that contains the file system')
parser.add_argument("dst_storage_url", metavar='<destination-storage-url>',
type=storage_url_type,
help='Storage URL of the destination backend')
parser.add_argument("--threads", type=int, default=3,
help='Number of threads to use')
return parser.parse_args(args)
@handle_on_return
def copy_loop(queue, src_backend_factory, dst_backend_factory, on_return):
'''Copy keys arriving in *queue* from *src_backend* to *dst_backend*
Terminate when None is received.
'''
src_backend = on_return.enter_context(src_backend_factory())
dst_backend = on_return.enter_context(dst_backend_factory())
tmpfh = on_return.enter_context(tempfile.TemporaryFile())
while True:
key = queue.get()
if key is None:
break
log.debug('reading object %s', key)
def do_read(fh):
tmpfh.seek(0)
tmpfh.truncate()
while True:
buf = fh.read(BUFSIZE)
if not buf:
break
tmpfh.write(buf)
return fh.metadata
metadata = src_backend.perform_read(do_read, key)
log.debug('writing object %s', key)
def do_write(fh):
tmpfh.seek(0)
while True:
buf = tmpfh.read(BUFSIZE)
if not buf:
break
fh.write(buf)
dst_backend.perform_write(do_write, key, metadata)
def main(args=None):
options = parse_args(args)
setup_logging(options)
try:
options.storage_url = options.src_storage_url
src_backend_factory = get_backend_factory(options.src_storage_url,
options.backend_options,
options.authfile, raw=True)
options.storage_url = options.dst_storage_url
dst_backend_factory = get_backend_factory(options.dst_storage_url,
options.backend_options,
options.authfile, raw=True)
except DanglingStorageURLError as exc:
raise QuietError(str(exc)) from None
queue = Queue(maxsize=options.threads)
threads = []
for _ in range(options.threads):
t = AsyncFn(copy_loop, queue, src_backend_factory,
dst_backend_factory)
# Don't wait for worker threads, gives deadlock if main thread
# terminates with exception
t.daemon = True
t.start()
threads.append(t)
with src_backend_factory() as backend:
stamp1 = 0
for (i, key) in enumerate(backend):
stamp2 = time.time()
if stamp2 - stamp1 > 1:
stamp1 = stamp2
sys.stdout.write('\rCopied %d objects so far...' % i)
sys.stdout.flush()
# Terminate early if any thread failed with an exception
for t in threads:
if not t.is_alive():
t.join_and_raise()
# Avoid blocking if all threads terminated
while True:
try:
queue.put(key, timeout=1)
except QueueFull:
pass
else:
break
for t in threads:
if not t.is_alive():
t.join_and_raise()
sys.stdout.write('\n')
queue.maxsize += len(threads)
for t in threads:
queue.put(None)
for t in threads:
t.join_and_raise()
if __name__ == '__main__':
main(sys.argv[1:])
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