benoitc / couch_zmq

About

couch_zmq is a zeromq endpoint for couchdb.

Install

Make sure Couchdb is installed on folder above the couch_zmq one. You can also change the path of couchdb installation by passing the path to **COUCHDB_SRC* environment variable..

$ make

(note during development you can use make dev command).

Add couch_zmq_pubsub server to couch configuration file local_dev.ini and edit the [daermons] section:

[daemons]
couch_zmq_pubsub={couch_zmq_pubsub, start_link, []}

Start couchdb:

$ export $COUCH_ZMQ=/path/to/couch_zmq
$ ERL_FLAGS="-pa $COUCH_ZMQ/ebin -pa $COUCH_ZMQ/deps/zmq/ebin" ./utils/run

Now you can suscribe to zeromq on tcp://127.0.0.1:7984 port by default (you can change the uri in section couch_zmq by adding db_updates key.

Here is a simple script in Python to listen db changes:

import zmq
context = zmq.Context()
socket = context.socket(zmq.SUB)
socket.connect("tcp://127.0.0.1:7984")

socket.setsockopt(zmq.SUBSCRIBE, "testdb")


while True:
    msg = socket.recv()
    print "Got", msg

Start it:

$ python test.py

Then create document in testdb database and listen for it:

$ python test.py
Got testdb {"seq":53,"id":"fa1ad2fc27dd45870698b2c199000277","changes":[{"rev":"53-d6de3b672dfe3ff22d176ddc9f2b2be2"}]}
Got testdb {"seq":54,"id":"fa1ad2fc27dd45870698b2c199000277","changes":[{"rev":"54-3e896e93ca745d8299d52fed313e8a64"}]}
Got testdb {"seq":55,"id":"fa1ad2fc27dd45870698b2c199000277","changes":[{"rev":"55-229b77d591deee30dbde967ca288ced1"}]}
Got testdb {"seq":56,"id":"fa1ad2fc27dd45870698b2c199000277","changes":[{"rev":"56-459ad8f3d6e0e99ba2438c715dba5e64"}]}

more soon.

TODO:

• Full CouchDB API access
• Changes notification handling / clients

Changelog:

version 0.01:

• Show the usage of couch_zmq. simple PUB/SUB pattern to sucribe to one or all db changes.