[zeromq-dev] Integrating ZeroMQ into existing systems?

[Chuck Remes]

On Jul 12, 2010, at 1:04 PM, Peter Alexander wrote:

> On Mon, Jul 12, 2010 at 1:45 PM, Chuck Remes <cremes.devlist at mac.com> wrote:
>> On Jul 12, 2010, at 12:18 PM, Steven Clark wrote:
>> 
>>> Forgive me a simple/stupid question here-
>>> 
>>> To make use of ZeroMQ, do both ends of a simple network connection
>>> need to be programmed with ZeroMQ, or can one endpoint use ZeroMQ and
>>> the other use low-level (Berkeley-style) sockets?
>>> 
>>> I have a situation where a device (microcontroller-based) connects
>>> periodically to a TCP server, sends/recvs some data, and disconnects.
>>> The server sends some filtered form of the data to other network
>>> endpoints. Currently everything is written using low-level sockets.
>>> I'd like to switch the server to use ZeroMQ so I can take advantage of
>>> Publisher/Subscriber sockets, etc for the distribution of data from
>>> the server. Should/can I make the link between the device and the
>>> server use ZeroMQ, given that I can't exactly port ZeroMQ to run on
>>> the microcontroller platform?
>>> 
>>> In the event that I can use it for the device connection, is the PAIR
>>> topology the correct one to use? What happens if the device doesn't
>>> shut down the connection cleanly (which happens fairly often)? Is
>>> there any danger of getting stuck in a FIN_WAIT state?
>> 
>> You can use regular sockets but you need to conform to the 0mq wire protocol.
>> 
>> See: http://api.zeromq.org/zmq_tcp.html
>> 
>> I think you could probably get something working on the microcontroller platform for SUB sockets pretty easily.
>> 
> 
> Correct me if I'm wrong here.. zmq_poll() can also be used. And I
> believe Martin is working on making this transparent for the future.

zmq_poll() doesn't help in this situation. He wants to be able to talk to 0mq sockets from a device that does NOT have the 0mq library. To do so, the application logic behind the regular socket will need to "speak" the 0mq wire format.

cr