The bloom is an in-memory persistent storage for determining whether an element is member of set (useful for counting uniqie events, sessions, storing approximated sets etc). Uses a Bloom filter - a space-efficient probabilistic data structure. Default configuration is sufficient for testing the set of 500,000,000 elements with false-positive probability 0.1%.

sudo apt-get install python-bitarray python-gevent or use pip to install corresponding modules.

Run sudo apt-get install build-essential libssl-dev libevent-dev in order to install dependencies. Then run make to build server or make static to build statically linked binary.

./bloom.py <filename_for_snapshot>

./bloom <filename_for_snapshot> or ./bloom.static <filename_for_snapshot> if you prefer statically linked version.

Test whether an element is a member of a set:

$ curl localhost:8888/check?e=sdfdsafdsafsadf
MISSING

Add an element to set:

$ curl localhost:8888/add?e=sdfdsafdsafsadf
ADDED

Check and add at a time:

$ curl localhost:8888/checkthenadd?e=sdfdsafdsafsadf
PRESENT

Server saves data to snapshot file on server exit. In addition, you may force the server to dump snapshot on disk by sending USR1 signal. Snapshot dumping process does not blocks serving request and uses copy-on-write method, so dumped data is always consistent.