Added utils.FileLikeIter
A really simple version of this was in container sync already, and I needed a more complete version for work I'm doing, and I noticed https://review.openstack.org/#/c/33405/ was also making use of it. So, here's a more full version. If https://review.openstack.org/#/c/33405/ lands before this, I'll update it accordingly. Change-Id: Iba66b6a97f65e312e04fdba273e8f4ad1d3e1594
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gholt
parent
60c1bc545e
commit
0a77f04893
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@ -199,6 +199,122 @@ def get_trans_id_time(trans_id):
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return None
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class FileLikeIter(object):
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def __init__(self, iterable):
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"""
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Wraps an iterable to behave as a file-like object.
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"""
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self.iterator = iter(iterable)
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self.buf = None
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self.closed = False
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def __iter__(self):
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return self
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def next(self):
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"""
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x.next() -> the next value, or raise StopIteration
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"""
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if self.closed:
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raise ValueError('I/O operation on closed file')
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if self.buf:
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rv = self.buf
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self.buf = None
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return rv
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else:
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return self.iterator.next()
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def read(self, size=-1):
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"""
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read([size]) -> read at most size bytes, returned as a string.
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If the size argument is negative or omitted, read until EOF is reached.
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Notice that when in non-blocking mode, less data than what was
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requested may be returned, even if no size parameter was given.
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"""
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if self.closed:
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raise ValueError('I/O operation on closed file')
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if size < 0:
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return ''.join(self)
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elif not size:
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chunk = ''
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elif self.buf:
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chunk = self.buf
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self.buf = None
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else:
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try:
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chunk = self.iterator.next()
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except StopIteration:
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return ''
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if len(chunk) > size:
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self.buf = chunk[size:]
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chunk = chunk[:size]
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return chunk
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def readline(self, size=-1):
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"""
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readline([size]) -> next line from the file, as a string.
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Retain newline. A non-negative size argument limits the maximum
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number of bytes to return (an incomplete line may be returned then).
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Return an empty string at EOF.
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"""
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if self.closed:
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raise ValueError('I/O operation on closed file')
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data = ''
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while '\n' not in data and (size < 0 or len(data) < size):
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if size < 0:
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chunk = self.read(1024)
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else:
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chunk = self.read(size - len(data))
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if not chunk:
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break
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data += chunk
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if '\n' in data:
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data, sep, rest = data.partition('\n')
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data += sep
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if self.buf:
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self.buf = rest + self.buf
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else:
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self.buf = rest
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return data
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def readlines(self, sizehint=-1):
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"""
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readlines([size]) -> list of strings, each a line from the file.
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Call readline() repeatedly and return a list of the lines so read.
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The optional size argument, if given, is an approximate bound on the
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total number of bytes in the lines returned.
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"""
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if self.closed:
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raise ValueError('I/O operation on closed file')
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lines = []
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while True:
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line = self.readline(sizehint)
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if not line:
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break
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lines.append(line)
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if sizehint >= 0:
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sizehint -= len(line)
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if sizehint <= 0:
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break
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return lines
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def close(self):
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"""
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close() -> None or (perhaps) an integer. Close the file.
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Sets data attribute .closed to True. A closed file cannot be used for
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further I/O operations. close() may be called more than once without
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error. Some kinds of file objects (for example, opened by popen())
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may return an exit status upon closing.
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"""
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self.iterator = None
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self.closed = True
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class FallocateWrapper(object):
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def __init__(self, noop=False):
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@ -27,47 +27,11 @@ from swift.common.direct_client import direct_get_object
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from swift.common.ring import Ring
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from swift.common.db import ContainerBroker
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from swift.common.utils import audit_location_generator, get_logger, \
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hash_path, config_true_value, validate_sync_to, whataremyips
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hash_path, config_true_value, validate_sync_to, whataremyips, FileLikeIter
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from swift.common.daemon import Daemon
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from swift.common.http import HTTP_UNAUTHORIZED, HTTP_NOT_FOUND
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class _Iter2FileLikeObject(object):
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"""
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Returns an iterator's contents via :func:`read`, making it look like a file
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object.
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"""
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def __init__(self, iterator):
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self.iterator = iterator
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self._chunk = ''
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def read(self, size=-1):
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"""
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read([size]) -> read at most size bytes, returned as a string.
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If the size argument is negative or omitted, read until EOF is reached.
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Notice that when in non-blocking mode, less data than what was
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requested may be returned, even if no size parameter was given.
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"""
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if size < 0:
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chunk = self._chunk
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self._chunk = ''
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return chunk + ''.join(self.iterator)
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chunk = self._chunk
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self._chunk = ''
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if chunk and len(chunk) <= size:
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return chunk
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try:
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chunk += self.iterator.next()
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except StopIteration:
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pass
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if len(chunk) <= size:
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return chunk
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self._chunk = chunk[size:]
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return chunk[:size]
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class ContainerSync(Daemon):
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"""
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Daemon to sync syncable containers.
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@ -409,7 +373,7 @@ class ContainerSync(Daemon):
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headers['x-timestamp'] = row['created_at']
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headers['x-container-sync-key'] = sync_key
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put_object(sync_to, name=row['name'], headers=headers,
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contents=_Iter2FileLikeObject(body),
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contents=FileLikeIter(body),
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proxy=self.proxy)
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self.container_puts += 1
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self.logger.increment('puts')
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@ -1325,6 +1325,124 @@ log_name = %(yarr)s'''
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MagicMock(side_effect=BaseException('test3')))
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class TestFileLikeIter(unittest.TestCase):
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def test_iter_file_iter(self):
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in_iter = ['abc', 'de', 'fghijk', 'l']
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chunks = []
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for chunk in utils.FileLikeIter(in_iter):
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chunks.append(chunk)
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self.assertEquals(chunks, in_iter)
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def test_next(self):
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in_iter = ['abc', 'de', 'fghijk', 'l']
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chunks = []
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iter_file = utils.FileLikeIter(in_iter)
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while True:
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try:
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chunk = iter_file.next()
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except StopIteration:
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break
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chunks.append(chunk)
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self.assertEquals(chunks, in_iter)
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def test_read(self):
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in_iter = ['abc', 'de', 'fghijk', 'l']
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chunks = []
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iter_file = utils.FileLikeIter(in_iter)
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self.assertEquals(iter_file.read(), ''.join(in_iter))
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def test_read_with_size(self):
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in_iter = ['abc', 'de', 'fghijk', 'l']
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chunks = []
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iter_file = utils.FileLikeIter(in_iter)
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while True:
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chunk = iter_file.read(2)
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if not chunk:
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break
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self.assertTrue(len(chunk) <= 2)
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chunks.append(chunk)
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self.assertEquals(''.join(chunks), ''.join(in_iter))
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def test_read_with_size_zero(self):
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# makes little sense, but file supports it, so...
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self.assertEquals(utils.FileLikeIter('abc').read(0), '')
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def test_readline(self):
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in_iter = ['abc\n', 'd', '\nef', 'g\nh', '\nij\n\nk\n', 'trailing.']
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lines = []
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iter_file = utils.FileLikeIter(in_iter)
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while True:
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line = iter_file.readline()
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if not line:
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break
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lines.append(line)
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self.assertEquals(
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lines,
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[v if v == 'trailing.' else v + '\n'
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for v in ''.join(in_iter).split('\n')])
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def test_readline2(self):
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self.assertEquals(
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utils.FileLikeIter(['abc', 'def\n']).readline(4),
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'abcd')
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def test_readline3(self):
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self.assertEquals(
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utils.FileLikeIter(['a' * 1111, 'bc\ndef']).readline(),
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('a' * 1111) + 'bc\n')
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def test_readline_with_size(self):
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in_iter = ['abc\n', 'd', '\nef', 'g\nh', '\nij\n\nk\n', 'trailing.']
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lines = []
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iter_file = utils.FileLikeIter(in_iter)
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while True:
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line = iter_file.readline(2)
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if not line:
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break
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lines.append(line)
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self.assertEquals(
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lines,
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['ab', 'c\n', 'd\n', 'ef', 'g\n', 'h\n', 'ij', '\n', '\n', 'k\n',
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'tr', 'ai', 'li', 'ng', '.'])
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def test_readlines(self):
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in_iter = ['abc\n', 'd', '\nef', 'g\nh', '\nij\n\nk\n', 'trailing.']
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lines = utils.FileLikeIter(in_iter).readlines()
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self.assertEquals(
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lines,
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[v if v == 'trailing.' else v + '\n'
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for v in ''.join(in_iter).split('\n')])
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def test_readlines_with_size(self):
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in_iter = ['abc\n', 'd', '\nef', 'g\nh', '\nij\n\nk\n', 'trailing.']
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iter_file = utils.FileLikeIter(in_iter)
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lists_of_lines = []
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while True:
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lines = iter_file.readlines(2)
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if not lines:
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break
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lists_of_lines.append(lines)
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self.assertEquals(
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lists_of_lines,
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[['ab'], ['c\n'], ['d\n'], ['ef'], ['g\n'], ['h\n'], ['ij'],
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['\n', '\n'], ['k\n'], ['tr'], ['ai'], ['li'], ['ng'], ['.']])
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def test_close(self):
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iter_file = utils.FileLikeIter('abcdef')
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self.assertEquals(iter_file.next(), 'a')
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iter_file.close()
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self.assertTrue(iter_file.closed, True)
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self.assertRaises(ValueError, iter_file.next)
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self.assertRaises(ValueError, iter_file.read)
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self.assertRaises(ValueError, iter_file.readline)
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self.assertRaises(ValueError, iter_file.readlines)
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# Just make sure repeated close calls don't raise an Exception
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iter_file.close()
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self.assertTrue(iter_file.closed, True)
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class TestStatsdLogging(unittest.TestCase):
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def test_get_logger_statsd_client_not_specified(self):
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logger = utils.get_logger({}, 'some-name', log_route='some-route')
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@ -66,8 +66,10 @@ class FakeContainerBroker(object):
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class TestContainerSync(unittest.TestCase):
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def test_Iter2FileLikeObject(self):
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flo = sync._Iter2FileLikeObject(iter(['123', '4567', '89', '0']))
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def test_FileLikeIter(self):
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# Retained test to show new FileLikeIter acts just like the removed
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# _Iter2FileLikeObject did.
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flo = sync.FileLikeIter(iter(['123', '4567', '89', '0']))
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expect = '1234567890'
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got = flo.read(2)
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@ -84,7 +86,7 @@ class TestContainerSync(unittest.TestCase):
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self.assertEquals(flo.read(), '')
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self.assertEquals(flo.read(2), '')
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flo = sync._Iter2FileLikeObject(iter(['123', '4567', '89', '0']))
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flo = sync.FileLikeIter(iter(['123', '4567', '89', '0']))
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self.assertEquals(flo.read(), '1234567890')
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self.assertEquals(flo.read(), '')
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self.assertEquals(flo.read(2), '')
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