Fixing bug with incrementing memcache with a negative number

openstack/swift

Code Issues Proposed changes

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David Goetz

2010年10月20日 10:31:50 -07:00

parent 8170d7246b

commit 3e8169e178

2 changed files with 27 additions and 1 deletions

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26
swift/common/memcached.py

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@@ -190,6 +190,32 @@ class MemcacheRing(object):

except Exception, e:

self._exception_occurred(server, e)

def decr(self, key, delta=1, timeout=0):

"""

Decrements a key which has a numeric value by delta.

If the key can't be found, it's added as 0. Memcached

will treat data values below 0 as 0 with incr/decr.

:param key: key

:param delta: amount to subtract to the value of key (or set

as the value if the key is not found)

:param timeout: ttl in memcache

"""

key = md5hash(key)

for (server, fp, sock) in self._get_conns(key):

try:

sock.sendall('decr %s%s\r\n' % (key, delta))

line = fp.readline().strip().split()

if line[0].upper() == 'NOT_FOUND':

line[0] = '0'

sock.sendall('add %s%d%d%s noreply\r\n%s\r\n' %

(key, 0, timeout, len(line[0]), line[0]))

ret = int(line[0].strip())

self._return_conn(server, fp, sock)

return ret

except Exception, e:

self._exception_occurred(server, e)

def delete(self, key):

"""

Deletes a key/value pair from memcache.

2
swift/common/middleware/ratelimit.py

View File

@@ -148,7 +148,7 @@ class RateLimitMiddleware(object):

max_sleep_m = self.max_sleep_time_seconds * self.clock_accuracy

if max_sleep_m - need_to_sleep_m <= self.clock_accuracy * 0.01:

# treat as no-op decrement time

self.memcache_client.incr(key, delta=-time_per_request_m)

self.memcache_client.decr(key, delta=time_per_request_m)

raise MaxSleepTimeHit("Max Sleep Time Exceeded: %s" %

need_to_sleep_m)