def downloadStream(self):
readable_fh, writable_fh = os.pipe()
with os.fdopen(readable_fh, 'r') as readable:
with os.fdopen(writable_fh, 'w') as writable:
def writer():
try:
if self.content is not None:
writable.write(self.content)
elif self.version:
headers = self._s3EncryptionHeaders()
key = self.outer.filesBucket.get_key(self.fileID, validate=False)
key.get_contents_to_file(writable,
headers=headers,
version_id=self.version)
else:
assert False
finally:
# This close() will send EOF to the reading end and ultimately cause
# the yield to return. It also makes the implict .close() done by the
# enclosing "with" context redundant but that should be ok since
# .close() on file objects are idempotent.
writable.close()
thread = ExceptionalThread(target=writer)
thread.start()
yield readable
thread.join()
def downloadStream(self):
readable_fh, writable_fh = os.pipe()
with os.fdopen(readable_fh, 'r') as readable:
with os.fdopen(writable_fh, 'w') as writable:
def writer():
try:
if self.content is not None:
writable.write(self.content)
elif self.version:
headers = self._s3EncryptionHeaders()
key = self.outer.filesBucket.get_key(self.fileID, validate=False)
key.get_contents_to_file(writable,
headers=headers,
version_id=self.version)
else:
assert False
finally:
# This close() will send EOF to the reading end and ultimately cause
# the yield to return. It also makes the implict .close() done by the
# enclosing "with" context redundant but that should be ok since
# .close() on file objects are idempotent.
writable.close()
thread = ExceptionalThread(target=writer)
thread.start()
yield readable
thread.join()
def uploadStream(self, multipart=True, allowInlining=True):
store = self.outer
readable_fh, writable_fh = os.pipe()
with os.fdopen(readable_fh, 'r') as readable:
with os.fdopen(writable_fh, 'w') as writable:
def multipartReader():
buf = readable.read(self.outer.partSize)
if allowInlining and len(
buf) <= self._maxInlinedSize():
self.content = buf
else:
headers = self._s3EncryptionHeaders()
upload = store.filesBucket.initiate_multipart_upload(
key_name=self.fileID, headers=headers)
try:
for part_num in itertools.count():
# There must be at least one part, even if the file is empty.
if len(buf) == 0 and part_num > 0: break
upload.upload_part_from_file(
fp=StringIO(buf),
# S3 part numbers are 1-based
part_num=part_num + 1,
headers=headers)
if len(buf) == 0: break
buf = readable.read(self.outer.partSize)
except:
upload.cancel_upload()
raise
else:
self.version = upload.complete_upload(
).version_id
def reader():
buf = readable.read()
if allowInlining and len(
buf) <= self._maxInlinedSize():
self.content = buf
else:
key = store.filesBucket.new_key(
key_name=self.fileID)
buf = StringIO(buf)
headers = self._s3EncryptionHeaders()
assert buf.len == key.set_contents_from_file(
fp=buf, headers=headers)
self.version = key.version_id
thread = ExceptionalThread(
target=multipartReader if multipart else reader)
thread.start()
yield writable
# The writable is now closed. This will send EOF to the readable and cause that
# thread to finish.
thread.join()
assert bool(self.version) == (self.content is None)
def _downloadStream(self, key, encrypt=True):
readable_fh, writable_fh = os.pipe()
with os.fdopen(readable_fh, 'r') as readable:
with os.fdopen(writable_fh, 'w') as writable:
def writer():
headers = self.encryptedHeaders if encrypt else self.headerValues
try:
key.get_file(writable, headers=headers)
finally:
writable.close()
thread = ExceptionalThread(target=writer)
thread.start()
yield readable
thread.join()
def uploadStream(self, multipart=True, allowInlining=True):
store = self.outer
readable_fh, writable_fh = os.pipe()
with os.fdopen(readable_fh, 'r') as readable:
with os.fdopen(writable_fh, 'w') as writable:
def multipartReader():
buf = readable.read(self.outer.partSize)
if allowInlining and len(buf) <= self._maxInlinedSize():
self.content = buf
else:
headers = self._s3EncryptionHeaders()
upload = store.filesBucket.initiate_multipart_upload(
key_name=self.fileID,
headers=headers)
try:
for part_num in itertools.count():
# There must be at least one part, even if the file is empty.
if len(buf) == 0 and part_num > 0: break
upload.upload_part_from_file(fp=StringIO(buf),
# S3 part numbers are 1-based
part_num=part_num + 1,
headers=headers)
if len(buf) == 0: break
buf = readable.read(self.outer.partSize)
except:
upload.cancel_upload()
raise
else:
self.version = upload.complete_upload().version_id
def reader():
buf = readable.read()
if allowInlining and len(buf) <= self._maxInlinedSize():
self.content = buf
else:
key = store.filesBucket.new_key(key_name=self.fileID)
buf = StringIO(buf)
headers = self._s3EncryptionHeaders()
assert buf.len == key.set_contents_from_file(fp=buf, headers=headers)
self.version = key.version_id
thread = ExceptionalThread(target=multipartReader if multipart else reader)
thread.start()
yield writable
# The writable is now closed. This will send EOF to the readable and cause that
# thread to finish.
thread.join()
assert bool(self.version) == (self.content is None)
def _downloadStream(self, key, encrypt=True):
readable_fh, writable_fh = os.pipe()
with os.fdopen(readable_fh, 'r') as readable:
with os.fdopen(writable_fh, 'w') as writable:
def writer():
headers = self.encryptedHeaders if encrypt else self.headerValues
try:
key.get_file(writable, headers=headers)
finally:
writable.close()
thread = ExceptionalThread(target=writer)
thread.start()
yield readable
thread.join()
def _uploadStream(self, key, update=False, encrypt=True):
readable_fh, writable_fh = os.pipe()
with os.fdopen(readable_fh, 'r') as readable:
with os.fdopen(writable_fh, 'w') as writable:
def writer():
headers = self.encryptedHeaders if encrypt else self.headerValues
if update:
try:
key.set_contents_from_stream(readable,
headers=headers)
except boto.exception.GSDataError:
if encrypt:
# https://github.com/boto/boto/issues/3518
# see self._writeFile for more
pass
else:
raise
else:
try:
# The if_condition kwarg insures that the existing key matches given
# generation (version) before modifying anything. Setting
# if_generation=0 insures key does not exist remotely
key.set_contents_from_stream(readable,
headers=headers,
if_generation=0)
except (boto.exception.GSResponseError,
boto.exception.GSDataError) as e:
if isinstance(e, boto.exception.GSResponseError):
if e.status == 412:
raise ConcurrentFileModificationException(
key.name)
else:
raise e
elif encrypt:
# https://github.com/boto/boto/issues/3518
# see self._writeFile for more
pass
else:
raise
thread = ExceptionalThread(target=writer)
thread.start()
yield writable
thread.join()
def _downloadStream(self, jobStoreFileID, container):
# The reason this is not in the writer is so we catch non-existant blobs early
blobProps = container.get_blob_properties(blob_name=jobStoreFileID)
encrypted = strict_bool(blobProps['x-ms-meta-encrypted'])
if encrypted and self.keyPath is None:
raise AssertionError(
'Content is encrypted but no key was provided.')
readable_fh, writable_fh = os.pipe()
with os.fdopen(readable_fh, 'r') as readable:
with os.fdopen(writable_fh, 'w') as writable:
def writer():
try:
chunkStartPos = 0
fileSize = int(blobProps['Content-Length'])
while chunkStartPos < fileSize:
chunkEndPos = chunkStartPos + self._maxAzureBlockBytes - 1
buf = container.get_blob(
blob_name=jobStoreFileID,
x_ms_range="bytes=%d-%d" %
(chunkStartPos, chunkEndPos))
if encrypted:
buf = encryption.decrypt(buf, self.keyPath)
writable.write(buf)
chunkStartPos = chunkEndPos + 1
finally:
# Ensure readers aren't left blocking if this thread crashes.
# This close() will send EOF to the reading end and ultimately cause the
# yield to return. It also makes the implict .close() done by the enclosing
# "with" context redundant but that should be ok since .close() on file
# objects are idempotent.
writable.close()
thread = ExceptionalThread(target=writer)
thread.start()
yield readable
thread.join()
def _uploadStream(self, key, update=False, encrypt=True):
readable_fh, writable_fh = os.pipe()
with os.fdopen(readable_fh, 'r') as readable:
with os.fdopen(writable_fh, 'w') as writable:
def writer():
headers = self.encryptedHeaders if encrypt else self.headerValues
if update:
try:
key.set_contents_from_stream(readable, headers=headers)
except boto.exception.GSDataError:
if encrypt:
# https://github.com/boto/boto/issues/3518
# see self._writeFile for more
pass
else:
raise
else:
try:
# The if_condition kwarg insures that the existing key matches given
# generation (version) before modifying anything. Setting
# if_generation=0 insures key does not exist remotely
key.set_contents_from_stream(readable, headers=headers, if_generation=0)
except (boto.exception.GSResponseError, boto.exception.GSDataError) as e:
if isinstance(e, boto.exception.GSResponseError):
if e.status == 412:
raise ConcurrentFileModificationException(key.name)
else:
raise e
elif encrypt:
# https://github.com/boto/boto/issues/3518
# see self._writeFile for more
pass
else:
raise
thread = ExceptionalThread(target=writer)
thread.start()
yield writable
thread.join()
def _downloadStream(self, jobStoreFileID, container):
# The reason this is not in the writer is so we catch non-existant blobs early
blobProps = container.get_blob_properties(blob_name=jobStoreFileID)
encrypted = strict_bool(blobProps['x-ms-meta-encrypted'])
if encrypted and self.keyPath is None:
raise AssertionError('Content is encrypted but no key was provided.')
readable_fh, writable_fh = os.pipe()
with os.fdopen(readable_fh, 'r') as readable:
with os.fdopen(writable_fh, 'w') as writable:
def writer():
try:
chunkStartPos = 0
fileSize = int(blobProps['Content-Length'])
while chunkStartPos < fileSize:
chunkEndPos = chunkStartPos + self._maxAzureBlockBytes - 1
buf = container.get_blob(blob_name=jobStoreFileID,
x_ms_range="bytes=%d-%d" % (chunkStartPos,
chunkEndPos))
if encrypted:
buf = encryption.decrypt(buf, self.keyPath)
writable.write(buf)
chunkStartPos = chunkEndPos + 1
finally:
# Ensure readers aren't left blocking if this thread crashes.
# This close() will send EOF to the reading end and ultimately cause the
# yield to return. It also makes the implict .close() done by the enclosing
# "with" context redundant but that should be ok since .close() on file
# objects are idempotent.
writable.close()
thread = ExceptionalThread(target=writer)
thread.start()
yield readable
thread.join()
def _uploadStream(self, jobStoreFileID, container, checkForModification=False, encrypted=None):
"""
:param encrypted: True to enforce encryption (will raise exception unless key is set),
False to prevent encryption or None to encrypt if key is set.
"""
if checkForModification:
try:
expectedVersion = container.get_blob_properties(blob_name=jobStoreFileID)['etag']
except WindowsAzureMissingResourceError:
expectedVersion = None
if encrypted is None:
encrypted = self.keyPath is not None
elif encrypted:
if self.keyPath is None:
raise RuntimeError('Encryption requested but no key was provided')
maxBlockSize = self._maxAzureBlockBytes
if encrypted:
# There is a small overhead for encrypted data.
maxBlockSize -= encryption.overhead
readable_fh, writable_fh = os.pipe()
with os.fdopen(readable_fh, 'r') as readable:
with os.fdopen(writable_fh, 'w') as writable:
def reader():
blockIDs = []
try:
while True:
buf = readable.read(maxBlockSize)
if len(buf) == 0:
# We're safe to break here even if we never read anything, since
# putting an empty block list creates an empty blob.
break
if encrypted:
buf = encryption.encrypt(buf, self.keyPath)
blockID = self._newFileID()
container.put_block(blob_name=jobStoreFileID,
block=buf,
blockid=blockID)
blockIDs.append(blockID)
except:
# This is guaranteed to delete any uncommitted
# blocks.
container.delete_blob(blob_name=jobStoreFileID)
raise
if checkForModification and expectedVersion is not None:
# Acquire a (60-second) write lock,
leaseID = container.lease_blob(blob_name=jobStoreFileID,
x_ms_lease_action='acquire')['x-ms-lease-id']
# check for modification,
blobProperties = container.get_blob_properties(blob_name=jobStoreFileID)
if blobProperties['etag'] != expectedVersion:
container.lease_blob(blob_name=jobStoreFileID,
x_ms_lease_action='release',
x_ms_lease_id=leaseID)
raise ConcurrentFileModificationException(jobStoreFileID)
# commit the file,
container.put_block_list(blob_name=jobStoreFileID,
block_list=blockIDs,
x_ms_lease_id=leaseID,
x_ms_meta_name_values=dict(
encrypted=str(encrypted)))
# then release the lock.
container.lease_blob(blob_name=jobStoreFileID,
x_ms_lease_action='release',
x_ms_lease_id=leaseID)
else:
# No need to check for modification, just blindly write over whatever
# was there.
container.put_block_list(blob_name=jobStoreFileID,
block_list=blockIDs,
x_ms_meta_name_values=dict(
encrypted=str(encrypted)))
thread = ExceptionalThread(target=reader)
thread.start()
yield writable
# The writable is now closed. This will send EOF to the readable and cause that
# thread to finish.
thread.join()
def _uploadStream(self,
jobStoreFileID,
container,
checkForModification=False,
encrypted=None):
"""
:param encrypted: True to enforce encryption (will raise exception unless key is set),
False to prevent encryption or None to encrypt if key is set.
"""
if checkForModification:
try:
expectedVersion = container.get_blob_properties(
blob_name=jobStoreFileID)['etag']
except AzureMissingResourceHttpError:
expectedVersion = None
if encrypted is None:
encrypted = self.keyPath is not None
elif encrypted:
if self.keyPath is None:
raise RuntimeError(
'Encryption requested but no key was provided')
maxBlockSize = self._maxAzureBlockBytes
if encrypted:
# There is a small overhead for encrypted data.
maxBlockSize -= encryption.overhead
readable_fh, writable_fh = os.pipe()
with os.fdopen(readable_fh, 'r') as readable:
with os.fdopen(writable_fh, 'w') as writable:
def reader():
blockIDs = []
try:
while True:
buf = readable.read(maxBlockSize)
if len(buf) == 0:
# We're safe to break here even if we never read anything, since
# putting an empty block list creates an empty blob.
break
if encrypted:
buf = encryption.encrypt(buf, self.keyPath)
blockID = self._newFileID()
container.put_block(blob_name=jobStoreFileID,
block=buf,
blockid=blockID)
blockIDs.append(blockID)
except:
# This is guaranteed to delete any uncommitted
# blocks.
container.delete_blob(blob_name=jobStoreFileID)
raise
if checkForModification and expectedVersion is not None:
# Acquire a (60-second) write lock,
leaseID = container.lease_blob(
blob_name=jobStoreFileID,
x_ms_lease_action='acquire')['x-ms-lease-id']
# check for modification,
blobProperties = container.get_blob_properties(
blob_name=jobStoreFileID)
if blobProperties['etag'] != expectedVersion:
container.lease_blob(blob_name=jobStoreFileID,
x_ms_lease_action='release',
x_ms_lease_id=leaseID)
raise ConcurrentFileModificationException(
jobStoreFileID)
# commit the file,
container.put_block_list(blob_name=jobStoreFileID,
block_list=blockIDs,
x_ms_lease_id=leaseID,
x_ms_meta_name_values=dict(
encrypted=str(encrypted)))
# then release the lock.
container.lease_blob(blob_name=jobStoreFileID,
x_ms_lease_action='release',
x_ms_lease_id=leaseID)
else:
# No need to check for modification, just blindly write over whatever
# was there.
container.put_block_list(blob_name=jobStoreFileID,
block_list=blockIDs,
x_ms_meta_name_values=dict(
encrypted=str(encrypted)))
thread = ExceptionalThread(target=reader)
thread.start()
yield writable
# The writable is now closed. This will send EOF to the readable and cause that
# thread to finish.
thread.join()
class ReadablePipe(object):
"""
An object-oriented wrapper for os.pipe. Clients should subclass it, implement
:meth:`.writeTo` to place data into the writable end of the pipe, then instantiate the class
as a context manager to get the writable end. See the example below.
>>> import sys, shutil
>>> class MyPipe(ReadablePipe):
... def writeTo(self, writable):
... writable.write('Hello, world!\\n')
>>> with MyPipe() as readable:
... shutil.copyfileobj(readable, sys.stdout)
Hello, world!
Each instance of this class creates a thread and invokes the :meth:`.writeTo` method in that
thread. The thread will be join()ed upon normal exit from the context manager, i.e. the body
of the `with` statement. If an exception occurs, the thread will not be joined but a
well-behaved :meth:`.writeTo` implementation will terminate shortly thereafter due to the
pipe having been closed.
Now, exceptions in the reader thread will be reraised in the main thread:
>>> class MyPipe(ReadablePipe):
... def writeTo(self, writable):
... raise RuntimeError('Hello, world!')
>>> with MyPipe() as readable:
... pass
Traceback (most recent call last):
...
RuntimeError: Hello, world!
More complicated, less illustrative tests:
Same as above, but provving that handles are closed:
>>> x = os.dup(0); os.close(x)
>>> class MyPipe(ReadablePipe):
... def writeTo(self, writable):
... raise RuntimeError('Hello, world!')
>>> with MyPipe() as readable:
... pass
Traceback (most recent call last):
...
RuntimeError: Hello, world!
>>> y = os.dup(0); os.close(y); x == y
True
Exceptions in the body of the with statement aren't masked, and handles are closed:
>>> x = os.dup(0); os.close(x)
>>> class MyPipe(ReadablePipe):
... def writeTo(self, writable):
... pass
>>> with MyPipe() as readable:
... raise RuntimeError('Hello, world!')
Traceback (most recent call last):
...
RuntimeError: Hello, world!
>>> y = os.dup(0); os.close(y); x == y
True
"""
__metaclass__ = ABCMeta
@abstractmethod
def writeTo(self, writable):
"""
Implement this method to read data from the pipe.
:param file writable: the file object representing the writable end of the pipe. Do not
explicitly invoke the close() method of the object, that will be done automatically.
"""
raise NotImplementedError()
def _writer(self):
with os.fdopen(self.writable_fh, 'w') as writable:
# FIXME: another race here, causing a redundant attempt to close in the main thread
self.writable_fh = None # signal to parent thread that we've taken over
self.writeTo(writable)
def __init__(self):
super(ReadablePipe, self).__init__()
self.writable_fh = None
self.readable = None
self.thread = None
def __enter__(self):
readable_fh, self.writable_fh = os.pipe()
self.readable = os.fdopen(readable_fh, 'r')
self.thread = ExceptionalThread(target=self._writer)
self.thread.start()
return self.readable
def __exit__(self, exc_type, exc_val, exc_tb):
try:
if exc_type is None:
if self.thread is not None:
# reraises any exception that was raised in the thread
self.thread.join()
finally:
self.readable.close()
# The responsibility for closing the writable end is generally that of the writer
# thread. To cover the small window before the writer takes over we also close it here.
writable_fh = self.writable_fh
if writable_fh is not None:
# FIXME: This is still racy. The writer thread could close it now, and someone
# else may immediately open a new file, reusing the file handle.
os.close(writable_fh)
class ReadablePipe(object):
"""
An object-oriented wrapper for os.pipe. Clients should subclass it, implement
:meth:`.writeTo` to place data into the writable end of the pipe, then instantiate the class
as a context manager to get the writable end. See the example below.
>>> import sys, shutil
>>> class MyPipe(ReadablePipe):
... def writeTo(self, writable):
... writable.write('Hello, world!\\n')
>>> with MyPipe() as readable:
... shutil.copyfileobj(readable, sys.stdout)
Hello, world!
Each instance of this class creates a thread and invokes the :meth:`.writeTo` method in that
thread. The thread will be join()ed upon normal exit from the context manager, i.e. the body
of the `with` statement. If an exception occurs, the thread will not be joined but a
well-behaved :meth:`.writeTo` implementation will terminate shortly thereafter due to the
pipe having been closed.
Now, exceptions in the reader thread will be reraised in the main thread:
>>> class MyPipe(ReadablePipe):
... def writeTo(self, writable):
... raise RuntimeError('Hello, world!')
>>> with MyPipe() as readable:
... pass
Traceback (most recent call last):
...
RuntimeError: Hello, world!
More complicated, less illustrative tests:
Same as above, but provving that handles are closed:
>>> x = os.dup(0); os.close(x)
>>> class MyPipe(ReadablePipe):
... def writeTo(self, writable):
... raise RuntimeError('Hello, world!')
>>> with MyPipe() as readable:
... pass
Traceback (most recent call last):
...
RuntimeError: Hello, world!
>>> y = os.dup(0); os.close(y); x == y
True
Exceptions in the body of the with statement aren't masked, and handles are closed:
>>> x = os.dup(0); os.close(x)
>>> class MyPipe(ReadablePipe):
... def writeTo(self, writable):
... pass
>>> with MyPipe() as readable:
... raise RuntimeError('Hello, world!')
Traceback (most recent call last):
...
RuntimeError: Hello, world!
>>> y = os.dup(0); os.close(y); x == y
True
"""
__metaclass__ = ABCMeta
@abstractmethod
def writeTo(self, writable):
"""
Implement this method to read data from the pipe.
:param file writable: the file object representing the writable end of the pipe. Do not
explicitly invoke the close() method of the object, that will be done automatically.
"""
raise NotImplementedError()
def _writer(self):
with os.fdopen(self.writable_fh, "w") as writable:
# FIXME: another race here, causing a redundant attempt to close in the main thread
self.writable_fh = None # signal to parent thread that we've taken over
self.writeTo(writable)
def __init__(self):
super(ReadablePipe, self).__init__()
self.writable_fh = None
self.readable = None
self.thread = None
def __enter__(self):
readable_fh, self.writable_fh = os.pipe()
self.readable = os.fdopen(readable_fh, "r")
self.thread = ExceptionalThread(target=self._writer)
self.thread.start()
return self.readable
def __exit__(self, exc_type, exc_val, exc_tb):
try:
if exc_type is None:
if self.thread is not None:
# reraises any exception that was raised in the thread
self.thread.join()
finally:
self.readable.close()
# The responsibility for closing the writable end is generally that of the writer
# thread. To cover the small window before the writer takes over we also close it here.
writable_fh = self.writable_fh
if writable_fh is not None:
# FIXME: This is still racy. The writer thread could close it now, and someone
# else may immediately open a new file, reusing the file handle.
os.close(writable_fh)
class ReadablePipe(with_metaclass(ABCMeta, object)):
"""
An object-oriented wrapper for os.pipe. Clients should subclass it, implement
:meth:`.writeTo` to place data into the writable end of the pipe, then instantiate the class
as a context manager to get the writable end. See the example below.
>>> import sys, shutil
>>> class MyPipe(ReadablePipe):
... def writeTo(self, writable):
... writable.write('Hello, world!\\n')
>>> with MyPipe() as readable:
... shutil.copyfileobj(readable, sys.stdout)
Hello, world!
Each instance of this class creates a thread and invokes the :meth:`.writeTo` method in that
thread. The thread will be join()ed upon normal exit from the context manager, i.e. the body
of the `with` statement. If an exception occurs, the thread will not be joined but a
well-behaved :meth:`.writeTo` implementation will terminate shortly thereafter due to the
pipe having been closed.
Now, exceptions in the reader thread will be reraised in the main thread:
>>> class MyPipe(ReadablePipe):
... def writeTo(self, writable):
... raise RuntimeError('Hello, world!')
>>> with MyPipe() as readable:
... pass
Traceback (most recent call last):
...
RuntimeError: Hello, world!
More complicated, less illustrative tests:
Same as above, but provving that handles are closed:
>>> x = os.dup(0); os.close(x)
>>> class MyPipe(ReadablePipe):
... def writeTo(self, writable):
... raise RuntimeError('Hello, world!')
>>> with MyPipe() as readable:
... pass
Traceback (most recent call last):
...
RuntimeError: Hello, world!
>>> y = os.dup(0); os.close(y); x == y
True
Exceptions in the body of the with statement aren't masked, and handles are closed:
>>> x = os.dup(0); os.close(x)
>>> class MyPipe(ReadablePipe):
... def writeTo(self, writable):
... pass
>>> with MyPipe() as readable:
... raise RuntimeError('Hello, world!')
Traceback (most recent call last):
...
RuntimeError: Hello, world!
>>> y = os.dup(0); os.close(y); x == y
True
"""
@abstractmethod
def writeTo(self, writable):
"""
Implement this method to read data from the pipe.
:param file writable: the file object representing the writable end of the pipe. Do not
explicitly invoke the close() method of the object, that will be done automatically.
"""
raise NotImplementedError()
def _writer(self):
try:
with os.fdopen(self.writable_fh, 'w') as writable:
self.writeTo(writable)
except IOError as e:
# The other side of the pipe may have been closed by the
# reading thread, which is OK.
if e.errno != errno.EPIPE:
raise
def __init__(self):
super(ReadablePipe, self).__init__()
self.writable_fh = None
self.readable = None
self.thread = None
def __enter__(self):
readable_fh, self.writable_fh = os.pipe()
self.readable = os.fdopen(readable_fh, 'r')
self.thread = ExceptionalThread(target=self._writer)
self.thread.start()
return self.readable
def __exit__(self, exc_type, exc_val, exc_tb):
# Close the read end of the pipe. The writing thread may
# still be writing to the other end, but this will wake it up
# if that's the case.
self.readable.close()
try:
if self.thread is not None:
# reraises any exception that was raised in the thread
self.thread.join()
except:
if exc_type is None:
# Only raise the child exception if there wasn't
# already an exception in the main thread
raise