Redis backend raises exception when calling get/set_multi with empty iterable/mapping #58
Description
Migrated issue, originally created by greggg (greggg)
Calling get_multi with an empty iterable:
#!python
from dogpile.cache import make_region
region = make_region().configure(
'dogpile.cache.redis',
arguments={
'host': 'localhost',
'port': 6379,
'db': 0,
'distributed_lock': True
}
)
region.get_multi([])
Results in:
File "/home/gg/dev/sandbox/dogpile.cache/dogpile/cache/region.py", line 509, in get_multi
backend_values = self.backend.get_multi(keys)
File "/home/gg/dev/sandbox/dogpile.cache/dogpile/cache/backends/redis.py", line 122, in get_multi
values = self.client.mget(keys)
File "/home/gg/.virtualenvs/dogpile/lib/python2.7/site-packages/redis/client.py", line 768, in mget
return self.execute_command('MGET', *args)
File "/home/gg/.virtualenvs/dogpile/lib/python2.7/site-packages/redis/client.py", line 461, in execute_command
return self.parse_response(connection, command_name, **options)
File "/home/gg/.virtualenvs/dogpile/lib/python2.7/site-packages/redis/client.py", line 471, in parse_response
response = connection.read_response()
File "/home/gg/.virtualenvs/dogpile/lib/python2.7/site-packages/redis/connection.py", line 339, in read_response
raise response
ResponseError: wrong number of arguments for 'mget' command
Calling set_multi with an empty mapping:
#!python
from dogpile.cache import make_region
region = make_region().configure(
'dogpile.cache.redis',
arguments={
'host': 'localhost',
'port': 6379,
'db': 0,
'distributed_lock': True
}
)
region.set_multi({})
Results in:
File "/home/gg/dev/sandbox/dogpile.cache/dogpile/cache/region.py", line 790, in set_multi
self.backend.set_multi(mapping)
File "/home/gg/dev/sandbox/dogpile.cache/dogpile/cache/backends/redis.py", line 142, in set_multi
self.client.mset(mapping)
File "/home/gg/.virtualenvs/dogpile/lib/python2.7/site-packages/redis/client.py", line 782, in mset
return self.execute_command('MSET', *items)
File "/home/gg/.virtualenvs/dogpile/lib/python2.7/site-packages/redis/client.py", line 461, in execute_command
return self.parse_response(connection, command_name, **options)
File "/home/gg/.virtualenvs/dogpile/lib/python2.7/site-packages/redis/client.py", line 471, in parse_response
response = connection.read_response()
File "/home/gg/.virtualenvs/dogpile/lib/python2.7/site-packages/redis/connection.py", line 339, in read_response
raise response
redis.exceptions.ResponseError: wrong number of arguments for 'mset' command
The other backends do not raise an exception in these cases, so for consistency, the Redis backend should not either.