606 lines
19 KiB
Python
606 lines
19 KiB
Python
|
# -*- coding: utf-8 -*-
|
||
|
"""Implements file-like objects for reading and writing from/to S3."""
|
||
|
|
||
|
import io
|
||
|
import contextlib
|
||
|
import functools
|
||
|
import itertools
|
||
|
import logging
|
||
|
|
||
|
import boto3
|
||
|
import botocore.client
|
||
|
import six
|
||
|
|
||
|
|
||
|
logger = logging.getLogger(__name__)
|
||
|
logger.addHandler(logging.NullHandler())
|
||
|
|
||
|
# Multiprocessing is unavailable in App Engine (and possibly other sandboxes).
|
||
|
# The only method currently relying on it is s3_iter_bucket, which is instructed
|
||
|
# whether to use it by the MULTIPROCESSING flag.
|
||
|
_MULTIPROCESSING = False
|
||
|
try:
|
||
|
import multiprocessing.pool
|
||
|
_MULTIPROCESSING = True
|
||
|
except ImportError:
|
||
|
logger.warning("multiprocessing could not be imported and won't be used")
|
||
|
|
||
|
START = 0
|
||
|
CURRENT = 1
|
||
|
END = 2
|
||
|
WHENCE_CHOICES = (START, CURRENT, END)
|
||
|
|
||
|
DEFAULT_MIN_PART_SIZE = 50 * 1024**2
|
||
|
"""Default minimum part size for S3 multipart uploads"""
|
||
|
MIN_MIN_PART_SIZE = 5 * 1024 ** 2
|
||
|
"""The absolute minimum permitted by Amazon."""
|
||
|
READ_BINARY = 'rb'
|
||
|
WRITE_BINARY = 'wb'
|
||
|
MODES = (READ_BINARY, WRITE_BINARY)
|
||
|
"""Allowed I/O modes for working with S3."""
|
||
|
|
||
|
BINARY_NEWLINE = b'\n'
|
||
|
DEFAULT_BUFFER_SIZE = 128 * 1024
|
||
|
|
||
|
|
||
|
def _range_string(start, stop=None):
|
||
|
#
|
||
|
# https://www.w3.org/Protocols/rfc2616/rfc2616-sec14.html#sec14.35
|
||
|
#
|
||
|
if stop is None:
|
||
|
return 'bytes=%d-' % start
|
||
|
return 'bytes=%d-%d' % (start, stop)
|
||
|
|
||
|
|
||
|
def _clamp(value, minval, maxval):
|
||
|
return max(min(value, maxval), minval)
|
||
|
|
||
|
|
||
|
def open(bucket_id, key_id, mode, **kwargs):
|
||
|
logger.debug('%r', locals())
|
||
|
if mode not in MODES:
|
||
|
raise NotImplementedError('bad mode: %r expected one of %r' % (mode, MODES))
|
||
|
|
||
|
encoding = kwargs.pop("encoding", "utf-8")
|
||
|
errors = kwargs.pop("errors", None)
|
||
|
newline = kwargs.pop("newline", None)
|
||
|
line_buffering = kwargs.pop("line_buffering", False)
|
||
|
s3_min_part_size = kwargs.pop("s3_min_part_size", DEFAULT_MIN_PART_SIZE)
|
||
|
|
||
|
if mode == READ_BINARY:
|
||
|
fileobj = SeekableBufferedInputBase(bucket_id, key_id, **kwargs)
|
||
|
elif mode == WRITE_BINARY:
|
||
|
fileobj = BufferedOutputBase(bucket_id, key_id, min_part_size=s3_min_part_size, **kwargs)
|
||
|
else:
|
||
|
assert False, 'unexpected mode: %r' % mode
|
||
|
|
||
|
return fileobj
|
||
|
|
||
|
|
||
|
class RawReader(object):
|
||
|
"""Read an S3 object."""
|
||
|
def __init__(self, s3_object):
|
||
|
self.position = 0
|
||
|
self._object = s3_object
|
||
|
self._body = s3_object.get()['Body']
|
||
|
|
||
|
def read(self, size=-1):
|
||
|
if size == -1:
|
||
|
return self._body.read()
|
||
|
return self._body.read(size)
|
||
|
|
||
|
|
||
|
class SeekableRawReader(object):
|
||
|
"""Read an S3 object."""
|
||
|
|
||
|
def __init__(self, s3_object):
|
||
|
self._object = s3_object
|
||
|
self._content_length = self._object.content_length
|
||
|
self.seek(0)
|
||
|
|
||
|
def seek(self, position):
|
||
|
"""Seek to the specified position (byte offset) in the S3 key.
|
||
|
|
||
|
:param int position: The byte offset from the beginning of the key.
|
||
|
"""
|
||
|
self._position = position
|
||
|
range_string = _range_string(self._position)
|
||
|
logger.debug('content_length: %r range_string: %r', self._content_length, range_string)
|
||
|
|
||
|
#
|
||
|
# Close old body explicitly.
|
||
|
# When first seek(), self._body is not exist. Catch the exception and do nothing.
|
||
|
#
|
||
|
try:
|
||
|
self._body.close()
|
||
|
except AttributeError as e:
|
||
|
pass
|
||
|
|
||
|
if position == self._content_length == 0 or position == self._content_length:
|
||
|
#
|
||
|
# When reading, we can't seek to the first byte of an empty file.
|
||
|
# Similarly, we can't seek past the last byte. Do nothing here.
|
||
|
#
|
||
|
self._body = io.BytesIO()
|
||
|
else:
|
||
|
self._body = self._object.get(Range=range_string)['Body']
|
||
|
|
||
|
def read(self, size=-1):
|
||
|
if self._position >= self._content_length:
|
||
|
return b''
|
||
|
if size == -1:
|
||
|
binary = self._body.read()
|
||
|
else:
|
||
|
binary = self._body.read(size)
|
||
|
self._position += len(binary)
|
||
|
return binary
|
||
|
|
||
|
|
||
|
class BufferedInputBase(io.BufferedIOBase):
|
||
|
def __init__(self, bucket, key, buffer_size=DEFAULT_BUFFER_SIZE,
|
||
|
line_terminator=BINARY_NEWLINE, **kwargs):
|
||
|
session = kwargs.pop(
|
||
|
's3_session',
|
||
|
boto3.Session(profile_name=kwargs.pop('profile_name', None))
|
||
|
)
|
||
|
s3 = session.resource('s3', **kwargs)
|
||
|
self._object = s3.Object(bucket, key)
|
||
|
self._raw_reader = RawReader(self._object)
|
||
|
self._content_length = self._object.content_length
|
||
|
self._current_pos = 0
|
||
|
self._buffer = b''
|
||
|
self._eof = False
|
||
|
self._buffer_size = buffer_size
|
||
|
self._line_terminator = line_terminator
|
||
|
|
||
|
#
|
||
|
# This member is part of the io.BufferedIOBase interface.
|
||
|
#
|
||
|
self.raw = None
|
||
|
|
||
|
#
|
||
|
# Override some methods from io.IOBase.
|
||
|
#
|
||
|
def close(self):
|
||
|
"""Flush and close this stream."""
|
||
|
logger.debug("close: called")
|
||
|
self._object = None
|
||
|
|
||
|
def readable(self):
|
||
|
"""Return True if the stream can be read from."""
|
||
|
return True
|
||
|
|
||
|
def seekable(self):
|
||
|
return False
|
||
|
|
||
|
#
|
||
|
# io.BufferedIOBase methods.
|
||
|
#
|
||
|
def detach(self):
|
||
|
"""Unsupported."""
|
||
|
raise io.UnsupportedOperation
|
||
|
|
||
|
def read(self, size=-1):
|
||
|
"""Read up to size bytes from the object and return them."""
|
||
|
if size == 0:
|
||
|
return b''
|
||
|
elif size < 0:
|
||
|
if len(self._buffer):
|
||
|
from_buf = self._read_from_buffer(len(self._buffer))
|
||
|
else:
|
||
|
from_buf = b''
|
||
|
self._current_pos = self._content_length
|
||
|
return from_buf + self._raw_reader.read()
|
||
|
|
||
|
#
|
||
|
# Return unused data first
|
||
|
#
|
||
|
if len(self._buffer) >= size:
|
||
|
return self._read_from_buffer(size)
|
||
|
|
||
|
#
|
||
|
# If the stream is finished, return what we have.
|
||
|
#
|
||
|
if self._eof:
|
||
|
return self._read_from_buffer(len(self._buffer))
|
||
|
|
||
|
#
|
||
|
# Fill our buffer to the required size.
|
||
|
#
|
||
|
# logger.debug('filling %r byte-long buffer up to %r bytes', len(self._buffer), size)
|
||
|
self._fill_buffer(size)
|
||
|
return self._read_from_buffer(size)
|
||
|
|
||
|
def read1(self, size=-1):
|
||
|
"""This is the same as read()."""
|
||
|
return self.read(size=size)
|
||
|
|
||
|
def readinto(self, b):
|
||
|
"""Read up to len(b) bytes into b, and return the number of bytes
|
||
|
read."""
|
||
|
data = self.read(len(b))
|
||
|
if not data:
|
||
|
return 0
|
||
|
b[:len(data)] = data
|
||
|
return len(data)
|
||
|
|
||
|
def readline(self, limit=-1):
|
||
|
"""Read up to and including the next newline. Returns the bytes read."""
|
||
|
if limit != -1:
|
||
|
raise NotImplementedError('limits other than -1 not implemented yet')
|
||
|
the_line = io.BytesIO()
|
||
|
while not (self._eof and len(self._buffer) == 0):
|
||
|
#
|
||
|
# In the worst case, we're reading self._buffer twice here, once in
|
||
|
# the if condition, and once when calling index.
|
||
|
#
|
||
|
# This is sub-optimal, but better than the alternative: wrapping
|
||
|
# .index in a try..except, because that is slower.
|
||
|
#
|
||
|
if self._line_terminator in self._buffer:
|
||
|
next_newline = self._buffer.index(self._line_terminator)
|
||
|
the_line.write(self._read_from_buffer(next_newline + 1))
|
||
|
break
|
||
|
else:
|
||
|
the_line.write(self._read_from_buffer(len(self._buffer)))
|
||
|
self._fill_buffer(self._buffer_size)
|
||
|
return the_line.getvalue()
|
||
|
|
||
|
def terminate(self):
|
||
|
"""Do nothing."""
|
||
|
pass
|
||
|
|
||
|
#
|
||
|
# Internal methods.
|
||
|
#
|
||
|
def _read_from_buffer(self, size):
|
||
|
"""Remove at most size bytes from our buffer and return them."""
|
||
|
# logger.debug('reading %r bytes from %r byte-long buffer', size, len(self._buffer))
|
||
|
assert size >= 0
|
||
|
part = self._buffer[:size]
|
||
|
self._buffer = self._buffer[size:]
|
||
|
self._current_pos += len(part)
|
||
|
# logger.debug('part: %r', part)
|
||
|
return part
|
||
|
|
||
|
def _fill_buffer(self, size):
|
||
|
while len(self._buffer) < size and not self._eof:
|
||
|
raw = self._raw_reader.read(size=self._buffer_size)
|
||
|
if len(raw):
|
||
|
self._buffer += raw
|
||
|
else:
|
||
|
logger.debug('reached EOF while filling buffer')
|
||
|
self._eof = True
|
||
|
|
||
|
|
||
|
class SeekableBufferedInputBase(BufferedInputBase):
|
||
|
"""Reads bytes from S3.
|
||
|
|
||
|
Implements the io.BufferedIOBase interface of the standard library."""
|
||
|
|
||
|
def __init__(self, bucket, key, buffer_size=DEFAULT_BUFFER_SIZE,
|
||
|
line_terminator=BINARY_NEWLINE, **kwargs):
|
||
|
session = kwargs.pop(
|
||
|
's3_session',
|
||
|
boto3.Session(profile_name=kwargs.pop('profile_name', None))
|
||
|
)
|
||
|
s3 = session.resource('s3', **kwargs)
|
||
|
self._object = s3.Object(bucket, key)
|
||
|
self._raw_reader = SeekableRawReader(self._object)
|
||
|
self._content_length = self._object.content_length
|
||
|
self._current_pos = 0
|
||
|
self._buffer = b''
|
||
|
self._eof = False
|
||
|
self._buffer_size = buffer_size
|
||
|
self._line_terminator = line_terminator
|
||
|
|
||
|
#
|
||
|
# This member is part of the io.BufferedIOBase interface.
|
||
|
#
|
||
|
self.raw = None
|
||
|
|
||
|
def seekable(self):
|
||
|
"""If False, seek(), tell() and truncate() will raise IOError.
|
||
|
|
||
|
We offer only seek support, and no truncate support."""
|
||
|
return True
|
||
|
|
||
|
def seek(self, offset, whence=START):
|
||
|
"""Seek to the specified position.
|
||
|
|
||
|
:param int offset: The offset in bytes.
|
||
|
:param int whence: Where the offset is from.
|
||
|
|
||
|
Returns the position after seeking."""
|
||
|
logger.debug('seeking to offset: %r whence: %r', offset, whence)
|
||
|
if whence not in WHENCE_CHOICES:
|
||
|
raise ValueError('invalid whence, expected one of %r' % WHENCE_CHOICES)
|
||
|
|
||
|
if whence == START:
|
||
|
new_position = offset
|
||
|
elif whence == CURRENT:
|
||
|
new_position = self._current_pos + offset
|
||
|
else:
|
||
|
new_position = self._content_length + offset
|
||
|
new_position = _clamp(new_position, 0, self._content_length)
|
||
|
self._current_pos = new_position
|
||
|
self._raw_reader.seek(new_position)
|
||
|
logger.debug('new_position: %r', self._current_pos)
|
||
|
|
||
|
self._buffer = b""
|
||
|
self._eof = self._current_pos == self._content_length
|
||
|
return self._current_pos
|
||
|
|
||
|
def tell(self):
|
||
|
"""Return the current position within the file."""
|
||
|
return self._current_pos
|
||
|
|
||
|
def truncate(self, size=None):
|
||
|
"""Unsupported."""
|
||
|
raise io.UnsupportedOperation
|
||
|
|
||
|
|
||
|
class BufferedOutputBase(io.BufferedIOBase):
|
||
|
"""Writes bytes to S3.
|
||
|
|
||
|
Implements the io.BufferedIOBase interface of the standard library."""
|
||
|
|
||
|
def __init__(self, bucket, key, min_part_size=DEFAULT_MIN_PART_SIZE, s3_upload=None, **kwargs):
|
||
|
if min_part_size < MIN_MIN_PART_SIZE:
|
||
|
logger.warning("S3 requires minimum part size >= 5MB; \
|
||
|
multipart upload may fail")
|
||
|
|
||
|
session = kwargs.pop(
|
||
|
's3_session',
|
||
|
boto3.Session(profile_name=kwargs.pop('profile_name', None))
|
||
|
)
|
||
|
s3 = session.resource('s3', **kwargs)
|
||
|
|
||
|
#
|
||
|
# https://stackoverflow.com/questions/26871884/how-can-i-easily-determine-if-a-boto-3-s3-bucket-resource-exists
|
||
|
#
|
||
|
try:
|
||
|
s3.meta.client.head_bucket(Bucket=bucket)
|
||
|
except botocore.client.ClientError:
|
||
|
raise ValueError('the bucket %r does not exist, or is forbidden for access' % bucket)
|
||
|
self._object = s3.Object(bucket, key)
|
||
|
self._min_part_size = min_part_size
|
||
|
self._mp = self._object.initiate_multipart_upload(**(s3_upload or {}))
|
||
|
|
||
|
self._buf = io.BytesIO()
|
||
|
self._total_bytes = 0
|
||
|
self._total_parts = 0
|
||
|
self._parts = []
|
||
|
|
||
|
#
|
||
|
# This member is part of the io.BufferedIOBase interface.
|
||
|
#
|
||
|
self.raw = None
|
||
|
|
||
|
#
|
||
|
# Override some methods from io.IOBase.
|
||
|
#
|
||
|
def close(self):
|
||
|
logger.debug("closing")
|
||
|
if self._buf.tell():
|
||
|
self._upload_next_part()
|
||
|
|
||
|
if self._total_bytes:
|
||
|
self._mp.complete(MultipartUpload={'Parts': self._parts})
|
||
|
logger.debug("completed multipart upload")
|
||
|
elif self._mp:
|
||
|
#
|
||
|
# AWS complains with "The XML you provided was not well-formed or
|
||
|
# did not validate against our published schema" when the input is
|
||
|
# completely empty => abort the upload, no file created.
|
||
|
#
|
||
|
# We work around this by creating an empty file explicitly.
|
||
|
#
|
||
|
logger.info("empty input, ignoring multipart upload")
|
||
|
assert self._mp, "no multipart upload in progress"
|
||
|
self._mp.abort()
|
||
|
|
||
|
self._object.put(Body=b'')
|
||
|
self._mp = None
|
||
|
logger.debug("successfully closed")
|
||
|
|
||
|
@property
|
||
|
def closed(self):
|
||
|
return self._mp is None
|
||
|
|
||
|
def writable(self):
|
||
|
"""Return True if the stream supports writing."""
|
||
|
return True
|
||
|
|
||
|
def tell(self):
|
||
|
"""Return the current stream position."""
|
||
|
return self._total_bytes
|
||
|
|
||
|
#
|
||
|
# io.BufferedIOBase methods.
|
||
|
#
|
||
|
def detach(self):
|
||
|
raise io.UnsupportedOperation("detach() not supported")
|
||
|
|
||
|
def write(self, b):
|
||
|
"""Write the given bytes (binary string) to the S3 file.
|
||
|
|
||
|
There's buffering happening under the covers, so this may not actually
|
||
|
do any HTTP transfer right away."""
|
||
|
if not isinstance(b, six.binary_type):
|
||
|
raise TypeError("input must be a binary string, got: %r", b)
|
||
|
|
||
|
# logger.debug("writing %r bytes to %r", len(b), self._buf)
|
||
|
|
||
|
self._buf.write(b)
|
||
|
self._total_bytes += len(b)
|
||
|
|
||
|
if self._buf.tell() >= self._min_part_size:
|
||
|
self._upload_next_part()
|
||
|
|
||
|
return len(b)
|
||
|
|
||
|
def terminate(self):
|
||
|
"""Cancel the underlying multipart upload."""
|
||
|
assert self._mp, "no multipart upload in progress"
|
||
|
self._mp.abort()
|
||
|
self._mp = None
|
||
|
|
||
|
#
|
||
|
# Internal methods.
|
||
|
#
|
||
|
def _upload_next_part(self):
|
||
|
part_num = self._total_parts + 1
|
||
|
logger.info("uploading part #%i, %i bytes (total %.3fGB)",
|
||
|
part_num, self._buf.tell(), self._total_bytes / 1024.0 ** 3)
|
||
|
self._buf.seek(0)
|
||
|
part = self._mp.Part(part_num)
|
||
|
upload = part.upload(Body=self._buf)
|
||
|
self._parts.append({'ETag': upload['ETag'], 'PartNumber': part_num})
|
||
|
logger.debug("upload of part #%i finished" % part_num)
|
||
|
|
||
|
self._total_parts += 1
|
||
|
self._buf = io.BytesIO()
|
||
|
|
||
|
def __enter__(self):
|
||
|
return self
|
||
|
|
||
|
def __exit__(self, exc_type, exc_val, exc_tb):
|
||
|
if exc_type is not None:
|
||
|
self.terminate()
|
||
|
else:
|
||
|
self.close()
|
||
|
|
||
|
|
||
|
def iter_bucket(bucket_name, prefix='', accept_key=lambda key: True,
|
||
|
key_limit=None, workers=16, retries=3):
|
||
|
"""
|
||
|
Iterate and download all S3 files under `bucket/prefix`, yielding out
|
||
|
`(key, key content)` 2-tuples (generator).
|
||
|
|
||
|
`accept_key` is a function that accepts a key name (unicode string) and
|
||
|
returns True/False, signalling whether the given key should be downloaded out or
|
||
|
not (default: accept all keys).
|
||
|
|
||
|
If `key_limit` is given, stop after yielding out that many results.
|
||
|
|
||
|
The keys are processed in parallel, using `workers` processes (default: 16),
|
||
|
to speed up downloads greatly. If multiprocessing is not available, thus
|
||
|
_MULTIPROCESSING is False, this parameter will be ignored.
|
||
|
|
||
|
Example::
|
||
|
|
||
|
>>> # get all JSON files under "mybucket/foo/"
|
||
|
>>> for key, content in iter_bucket(bucket_name, prefix='foo/', accept_key=lambda key: key.endswith('.json')):
|
||
|
... print key, len(content)
|
||
|
|
||
|
>>> # limit to 10k files, using 32 parallel workers (default is 16)
|
||
|
>>> for key, content in iter_bucket(bucket_name, key_limit=10000, workers=32):
|
||
|
... print key, len(content)
|
||
|
"""
|
||
|
#
|
||
|
# If people insist on giving us bucket instances, silently extract the name
|
||
|
# before moving on. Works for boto3 as well as boto.
|
||
|
#
|
||
|
try:
|
||
|
bucket_name = bucket_name.name
|
||
|
except AttributeError:
|
||
|
pass
|
||
|
|
||
|
total_size, key_no = 0, -1
|
||
|
key_iterator = _list_bucket(bucket_name, prefix=prefix, accept_key=accept_key)
|
||
|
download_key = functools.partial(_download_key, bucket_name=bucket_name, retries=retries)
|
||
|
|
||
|
with _create_process_pool(processes=workers) as pool:
|
||
|
result_iterator = pool.imap_unordered(download_key, key_iterator)
|
||
|
for key_no, (key, content) in enumerate(result_iterator):
|
||
|
if True or key_no % 1000 == 0:
|
||
|
logger.info(
|
||
|
"yielding key #%i: %s, size %i (total %.1fMB)",
|
||
|
key_no, key, len(content), total_size / 1024.0 ** 2
|
||
|
)
|
||
|
yield key, content
|
||
|
total_size += len(content)
|
||
|
|
||
|
if key_limit is not None and key_no + 1 >= key_limit:
|
||
|
# we were asked to output only a limited number of keys => we're done
|
||
|
break
|
||
|
logger.info("processed %i keys, total size %i" % (key_no + 1, total_size))
|
||
|
|
||
|
|
||
|
def _list_bucket(bucket_name, prefix='', accept_key=lambda k: True):
|
||
|
client = boto3.client('s3')
|
||
|
ctoken = None
|
||
|
|
||
|
while True:
|
||
|
response = client.list_objects_v2(Bucket=bucket_name, Prefix=prefix)
|
||
|
try:
|
||
|
content = response['Contents']
|
||
|
except KeyError:
|
||
|
pass
|
||
|
else:
|
||
|
for c in content:
|
||
|
key = c['Key']
|
||
|
if accept_key(key):
|
||
|
yield key
|
||
|
ctoken = response.get('NextContinuationToken', None)
|
||
|
if not ctoken:
|
||
|
break
|
||
|
|
||
|
|
||
|
def _download_key(key_name, bucket_name=None, retries=3):
|
||
|
if bucket_name is None:
|
||
|
raise ValueError('bucket_name may not be None')
|
||
|
|
||
|
#
|
||
|
# https://geekpete.com/blog/multithreading-boto3/
|
||
|
#
|
||
|
session = boto3.session.Session()
|
||
|
s3 = session.resource('s3')
|
||
|
bucket = s3.Bucket(bucket_name)
|
||
|
|
||
|
# Sometimes, https://github.com/boto/boto/issues/2409 can happen because of network issues on either side.
|
||
|
# Retry up to 3 times to ensure its not a transient issue.
|
||
|
for x in range(retries + 1):
|
||
|
try:
|
||
|
content_bytes = _download_fileobj(bucket, key_name)
|
||
|
except botocore.client.ClientError:
|
||
|
# Actually fail on last pass through the loop
|
||
|
if x == retries:
|
||
|
raise
|
||
|
# Otherwise, try again, as this might be a transient timeout
|
||
|
pass
|
||
|
else:
|
||
|
return key_name, content_bytes
|
||
|
|
||
|
|
||
|
def _download_fileobj(bucket, key_name):
|
||
|
#
|
||
|
# This is a separate function only because it makes it easier to inject
|
||
|
# exceptions during tests.
|
||
|
#
|
||
|
buf = io.BytesIO()
|
||
|
bucket.download_fileobj(key_name, buf)
|
||
|
return buf.getvalue()
|
||
|
|
||
|
|
||
|
class DummyPool(object):
|
||
|
"""A class that mimics multiprocessing.pool.Pool for our purposes."""
|
||
|
def imap_unordered(self, function, items):
|
||
|
return six.moves.map(function, items)
|
||
|
|
||
|
def terminate(self):
|
||
|
pass
|
||
|
|
||
|
|
||
|
@contextlib.contextmanager
|
||
|
def _create_process_pool(processes=1):
|
||
|
if _MULTIPROCESSING and processes:
|
||
|
logger.info("creating pool with %i workers", processes)
|
||
|
pool = multiprocessing.pool.Pool(processes=processes)
|
||
|
else:
|
||
|
logger.info("creating dummy pool")
|
||
|
pool = DummyPool()
|
||
|
yield pool
|
||
|
pool.terminate()
|