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Script to output the token range ownership for Cassandra nodes.
#!/usr/bin/env python
"""Script to output the token range ownership for Cassandra nodes.
usage:
$ ./token_range.py --interactive 154009024815050802110273337963779530663 141704132449535340642001248672108470009 102889564695022956386161396156024583904
154009024815050802110273337963779530663 141704132449535340642001248672108470009 102889564695022956386161396156024583904
69.95% - 102889564695022956386161396156024583904
22.81% - 141704132449535340642001248672108470009
7.23% - 154009024815050802110273337963779530663
"""
import argparse
import sys
def get_parser():
parser = argparse.ArgumentParser(prog="Token Buddy",
description="In a world where tokens are unbalanced.")
parser.add_argument("tokens", metavar="token", type=str, nargs="+",
help="Space separated list of tokens.")
parser.add_argument("--interactive", "-i", default=False,
action='store_true', help="Accept token list from prompt.")
return parser
def describe_ownership(tokens):
if len(tokens) == 1:
return zip([1], tokens)
#order the tokens
tokens.sort()
# list of the tokens offset to the right 1
# first item is the diff between the last token and the max token
# is -ve because it will be subtracted from th first token
max_token = 2 ** 127 #change this to 10 if you want to test things
offset_tokens = [0-(max_token-tokens[-1])] + tokens[:-1]
#diff between each token and it's previous
deltas = [
t - prev_t
for t, prev_t in zip(tokens, offset_tokens)
]
# from RP ownership is
# ((token - prev_token + max_token) % max_token) / max_token
ownerships = [
(((delta + max_token) % max_token) / (max_token * 1.0))
for delta in deltas
]
return zip(ownerships, tokens)
def main():
parser = get_parser()
args = parser.parse_args()
def gen_tokens():
if args.tokens:
yield args.tokens
if args.interactive:
line = "true"
while line:
try:
line = raw_input("Next tokens: ")
except (EOFError, KeyboardInterrupt):
line = None
if line:
yield line.split(" ")
for tokens in gen_tokens():
tokens = [int(i) for i in tokens]
print " ".join(str(i) for i in tokens)
print "\n".join(
"{0:>6.2%} - {1}".format(own, t)
for own, t in describe_ownership(tokens)
)
print "\n"
return
if __name__ == "__main__":
sys.exit(main())
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