# pbdZMQ v0.2-5

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## Programming with Big Data -- Interface to ZeroMQ

'ZeroMQ' is a well-known library for high-performance asynchronous messaging in scalable, distributed applications. This package provides high level R wrapper functions to easily utilize 'ZeroMQ'. We mainly focus on interactive client/server programming frameworks. For convenience, a minimal 'ZeroMQ' library (4.1.0 rc1) is shipped with 'pbdZMQ', which can be used if no system installation of 'ZeroMQ' is available. A few wrapper functions compatible with 'rzmq' are also provided.

# pbdZMQ

• Status:
• Author: See section below.

pbdZMQ is an R package providing a simplified interface to ZeroMQ with a focus on client/server programming frameworks. Notably, pbdZMQ should allow for the use of ZeroMQ on Windows platforms.

## Interfaces

The package contains 3 separate interfaces:

1. One modeled after the ZeroMQ C interface (see help("czmq"))
2. One modeled after the PyZMQ interface (see help("pyzmq"))
3. One modeled after the rzmq interface (see help("rzmq"))

## Client/Server Example

The primary focus of pbdZMQ is for building client/server interfaces for R. An example of this can be found in the pbdCS package, which uses this model to control batch MPI servers interactively. There are also several illustrative examples in the pbdZMQ package vignette.

The basic idea is that you need a server R process, and a separate client R process. For demonstration/simplicity, assume they are both running on the same machine. The server we describe here is very basic. You can see a more detailed example in the pbdZMQ package vignette.

#### Server

Save the following as, say, server.r and run it in batch by running Rscript server.r from a terminal.

library(pbdZMQ)
context = zmq$Context() socket = context$socket("ZMQ_REP")
socket$bind("tcp://*:55555") cat("Client command: ") msg <- socket$receive()

cat(msg, "\n")
socket$send("Message received!")  #### Client From an interactive R session (not in batch), enter the following: library(pbdZMQ) context = zmq$Context()
socket = context$socket("ZMQ_REQ") socket$connect("tcp://localhost:55555")

socket$send("1+1") socket$receive()


If all goes well, your message should be sent from the client to the server, before your server terminates.

For an example of how to do this more persistently, see the pbdZMQ package vignette.

## Installation

pbdZMQ requires

• R version 3.0.0 or higher.
• Linux, Mac OSX, Windows, or FreeBSD.
• libzmq >= 4.0.4.
• Solaris 10 requiring external libzmq 4.0.7 and OpenCSW.

A distribution of libzmq is shipped with pbdZMQ for convenience. However, if you already have a system installation of ZeroMQ, then it is simple to use that with pbdZMQ. Full details on installation and troubleshooting can be found in the package vignette, located at inst/doc/pbdMPI-guide.pdf of the pbdZMQ source tree.

The package can be installed from the CRAN via the usual install.packages("pbdZMQ"), or via the devtools package:

library(devtools)
install_github("RBigData/pbdZMQ")


## Authors

pbdMPI is authored and maintained by:

• Wei-Chen Chen
• Drew Schmidt
• Christian Heckendorf
• George Ostrouchov

• Whit Armstrong (some functions are modified from rzmq for backwards compatibility)
• Brian Ripley (C code of shellexec)
• The R Core team (some functions are modified from the R source code)

For the distribution of ZeroMQ that is shipped with pbdZMQ, you can find details of authorship and copyright in inst/zmq_copyright/ of the pbdZMQ source tree, or under zmq_copyright/ of a binary installation of pbdZMQ.

## Functions in pbdZMQ

 Name Description Set Control Functions Set controls in pbdZMQ Initial Control Functions Initial controls in pbdZMQ ZMQ Control Environment Sets of controls in pbdZMQ. Context Functions Context Functions address Form an Address/Endpoint Send Receive Functions Send Receive Functions Socket Functions Socket Functions File Transfer Functions File Transfer Functions Message Function Message Functions pbdZMQ-package Programming with Big Data -- Interface to ZeroMQ New Poll Functions New Poll Functions Send Receive Multiple Raw Buffers Send Receive Multiple Raw Buffers PyZMQ-like Interface R6 ZMQ Interface Poll Functions Poll Functions C-like Wrapper Functions for ZeroMQ The C-like ZeroMQ Interface random_port Random Port Wrapper Functions for rzmq All Wrapper Functions for rzmq shellexec.wcc Shell Execution via cmd windows Utility Functions Utility Functions ZMQ Control Functions Sets of controls in pbdZMQ. No Results!