class Eraser(object):
"""A wrapper for pyeclib erasure coding driver (ECDriver)"""
def __init__(self,
ec_k,
ec_m,
ec_type="liberasurecode_rs_vand",
aes_enabled=True):
self.ec_type = ec_type
if aes_enabled:
self.aes = AESDriver()
logger.info("Eraser will use AES encryption")
else:
logger.info("Eraser will not use AES encryption")
expected_module_name = "drivers." + ec_type.lower() + "_driver"
expected_class_name = ec_type[0].upper() + ec_type[1:].lower(
) + "Driver"
try:
mod = __import__(expected_module_name,
fromlist=[expected_class_name])
driver_class = None
driver_class = getattr(mod, expected_class_name)
self.driver = driver_class(k=ec_k,
m=ec_m,
ec_type=ec_type,
hd=None)
except (ImportError, AttributeError):
logger.exception("Driver " + ec_type +
" could not be loaded as a custom driver")
try:
self.driver = ECDriver(k=ec_k, m=ec_m, ec_type=ec_type)
except Exception as error:
logger.exception("Driver " + ec_type +
" could not be loaded by pyeclib")
raise error
def encode(self, data):
"""Encode a string of bytes in flattened string of byte strips"""
payload = data
if hasattr(self, 'aes'):
payload = self.aes.encode(data)[0]
strips = self.driver.encode(payload)
return strips
def decode(self, strips):
"""Decode byte strips in a string of bytes"""
payload = self.driver.decode(strips)
if hasattr(self, 'aes'):
return self.aes.decode([payload])
return payload
def reconstruct(self, available_payload_fragments, missing_indices):
"""
Reconstruct missing fragments of data
Args:
available_payload_fragments(list(bytes)): Available fragments of data
missing_indices(list(int)): List of the indices of the missing blocks
Returns:
list(bytes): A list of the reconstructed fragments
"""
return self.driver.reconstruct(available_payload_fragments,
missing_indices)
def fragments_needed(self, missing_indices):
"""
Return a list of the fragments needed to recover the missing ones
Args:
missing_indices(list(int)): The list of indices of the fragments to recover
Returns:
list(int): A list of the indices of the fragments required to recover the missing ones
"""
return self.driver.fragments_needed(missing_indices)
# (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
# LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
# ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
import pyeclib
from pyeclib.ec_iface import ECDriver
import random
import string
import sys
import os
import argparse
parser = argparse.ArgumentParser(
description='PyECLib tool to determine fragment indexes needed to '
'recover missing fragments.')
parser.add_argument('k', type=int, help='number of data elements')
parser.add_argument('m', type=int, help='number of parity elements')
parser.add_argument('ec_type', help='EC algorithm used')
parser.add_argument('missing_fragments', type=int, metavar='missing_fragment',
nargs='+', help='missing_fragments')
args = parser.parse_args()
ec_driver = ECDriver(k=args.k, m=args.m, ec_type=args.ec_type)
fragments_needed = ec_driver.fragments_needed(args.missing_fragments)
print(fragments_needed)
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
import pyeclib
from pyeclib.ec_iface import ECDriver
import random
import string
import sys
import os
import argparse
parser = argparse.ArgumentParser(
description='PyECLib tool to determine fragment indexes needed to '
'recover missing fragments.')
parser.add_argument('k', type=int, help='number of data elements')
parser.add_argument('m', type=int, help='number of parity elements')
parser.add_argument('ec_type', help='EC algorithm used')
parser.add_argument('missing_fragments',
type=int,
metavar='missing_fragment',
nargs='+',
help='missing_fragments')
args = parser.parse_args()
ec_driver = ECDriver(k=args.k, m=args.m, ec_type=args.ec_type)
fragments_needed = ec_driver.fragments_needed(args.missing_fragments)
print(fragments_needed)
