python-oserrors

oserrors is a Python 3 module which provides constructors for OSError exception subclasses.

Use cases

oserrors is designed as a drop-in module for any Python library that needs to return OSError subclasses, for providing a low-level style API.

Usage

This module contains helpers for properly raising OSError subclasses.

>>> raise file_exists()
Traceback (most recent call last):
    ...
FileExistsError: [Errno 17] File exists
>>> raise file_exists('foo')
Traceback (most recent call last):
    ...
FileExistsError: [Errno 17] File exists: 'foo'
>>> raise file_exists('foo', 'bar')
Traceback (most recent call last):
    ...
FileExistsError: [Errno 17] File exists: 'foo' -> 'bar'

Error codes and message text is handled automatically, and the attributes filename and filename2 are set on the error object; see Python docs on OSError for details.

BlockingIOError takes an extra argument to set the attribute characters_written; see Python docs on BlockingIOError for details.

>>> raise blocking_io_eagain('foo', 'bar', 5)
Traceback (most recent call last):
    ...
BlockingIOError: [Errno 11] Resource temporarily unavailable: 'foo' -> 'bar'

Arguments can be passed by parameter name:

>>> raise blocking_io_eagain(filename='foo', filename2='bar', written=5)
Traceback (most recent call last):
    ...
BlockingIOError: [Errno 11] Resource temporarily unavailable: 'foo' -> 'bar'
>>> raise blocking_io_eagain(written=5)
Traceback (most recent call last):
    ...
BlockingIOError: [Errno 11] Resource temporarily unavailable

This module also exports the following pre-made constructor functions, which return an OSError object with the given error code:

• blocking_io_eagain(): errno.EAGAIN
• blocking_io_ealready(): errno.EALREADY
• blocking_io_ewouldblock(): errno.EWOULDBLOCK
• blocking_io_einprogress(): errno.EINPROGRESS
• child_process(): errno.ECHILD
• broken_pipe_eshutdown(): errno.ESHUTDOWN
• broken_pipe_epipe(): errno.EPIPE
• connection_aborted(): errno.ECONNABORTED
• connection_refused(): errno.ECONNREFUSED
• connection_reset(): errno.ECONNRESET
• file_exists(): errno.EEXIST
• file_not_found(): errno.ENOENT
• interrupted(): errno.EINTR
• is_a_directory(): errno.EISDIR
• not_a_directory(): errno.ENOTDIR
• permission_eacces(): errno.EACCES
• permission_eperm(): errno.EPERM
• process_lookup(): errno.ESRCH
• timeout(): errno.ETIMEDOUT

You can also make your own OSError builders by supplying an error code:

>>> import errno
>>> enoent_error = oserror(errno.ENOENT)
>>> raise enoent_error('foo')
Traceback (most recent call last):
    ...
FileNotFoundError: [Errno 2] No such file or directory: 'foo'