A Twisted Library for ZeroMQ
Note that though initially based on the work in txZMQ, this project is almost a
complete rewrite. tx0mq started life as a
git pull from txZMQ, in the event
that they ever wanted to merge it back in, it would be trivial to do so.
tx0mq provides for the easy integration of ZeroMQ sockets into the Twisted event loop (reactor).
Like txZMQ before it, tx0mq Supports CPython and PyPy.
- ZeroMQ library >= 2.1 (heavily tested with 2.1.4)
Python packages required:
- pyzmq (for CPython)
- pyzmq-ctypes (for PyPy)
tx0mq introduces support for general ZeroMQ sockets by class
that can do basic event loop integration, sending-receiving messages in
non-blocking manner, scatter-gather for multipart messages.
Special descendants of that class,
add special nice features for PUB/SUB sockets.
Request/reply pattern is achieved via XREQ/XREP sockets and classes
ZmqXREPConection (by verterok).
Other socket types could be easily derived from
In tx0mq, different considerations need to be made than with standard Twisted code that use TCP and UDP. From the zguide :
* ØMQ sockets carry messages, rather than bytes (as in TCP) or frames (as in UDP). A message is a length-specified blob of binary data. We'll come to messages shortly, their design is optimized for performance and thus somewhat tricky to understand. * ØMQ sockets do their I/O in a background thread. This means that messages arrive in a local input queue, and are sent from a local output queue, no matter what your application is busy doing. These are configurable memory queues, by the way. * ØMQ sockets can, depending on the socket type, be connected to (or from, it's the same) many other sockets. Where TCP emulates a one-to-one phone call, ØMQ implements one-to-many (like a radio broadcast), many-to-many (like a post office), many-to-one (like a mail box), and even one-to-one. * ØMQ sockets can send to many endpoints (creating a fan-out model), or receive from many endpoints (creating a fan-in model).
- Thoughts on integration with Twisted:
We are slowly adding tx0mq versions of:
- all the Python examples in the zguide, and
- the examples that come with the pyzmq source.
They are available for your viewing pleasure in the examples directory.
Source code for tx0mq is available at github, forks and pull requests are welcome.