ZeroMQ (also spelled ØMQ, 0MQ or ZMQ) is an asynchronous

messaging A message is a discrete unit of communication intended by the source for consumption by some recipient or group of recipients. A message may be delivered by various means, including courier, telegraphy, carrier pigeon and electronic bus. ...

library, aimed at use in

distributed Distribution may refer to: Mathematics *Distribution (mathematics), generalized functions used to formulate solutions of partial differential equations *Probability distribution, the probability of a particular value or value range of a varia ...

or concurrent applications. It provides a

message queue In computer science, message queues and mailboxes are software-engineering components typically used for inter-process communication (IPC), or for inter- thread communication within the same process. They use a queue for messaging – the ...

, but unlike

message-oriented middleware Message-oriented middleware (MOM) is software or hardware infrastructure supporting sending and receiving messages between distributed systems. MOM allows application modules to be distributed over heterogeneous platforms and reduces the complex ...

, a ZeroMQ system can run without a dedicated

message broker A message broker (also known as an integration broker or interface engine) is an intermediary computer program module that translates a message from the formal messaging protocol of the sender to the formal messaging protocol of the receiver. Mess ...

; the zero in the name is for zero broker. The library's API is designed to resemble

Berkeley sockets Berkeley sockets is an application programming interface (API) for Internet sockets and Unix domain sockets, used for inter-process communication (IPC). It is commonly implemented as a library of linkable modules. It originated with the 4.2BSD ...

. ZeroMQ is developed by a large community of contributors, founded by iMatix, which holds the domain name and trademarks. There are third-party bindings for many popular programming languages.

Technology

The ZeroMQ API provides ''sockets'' (a kind of generalization over the traditional IP and

Unix domain socket A Unix domain socket aka UDS or IPC socket ( inter-process communication socket) is a data communications endpoint for exchanging data between processes executing on the same host operating system. It is also referred to by its address family AF_U ...

s), each of which can represent a

many-to-many Many-to-many communication occurs when information is shared between groups. Members of a group receive information from multiple senders. Wikis are a type of many-to-many communication, where multiple editors collaborate to create content that ...

connection between endpoints. Operating with a message-wise granularity, they require that a

messaging pattern In software architecture, a messaging pattern is an architectural pattern which describes how two different parts of an application, or different systems connect and communicate with each other. There are many aspects to the concept of messaging w ...

be used, and are particularly optimized for that kind of pattern. The basic ZeroMQ patterns are: ; Request–reply :Connects a set of clients to a set of services. This is a

remote procedure call In distributed computing, a remote procedure call (RPC) is when a computer program causes a procedure (subroutine) to execute in a different address space (commonly on another computer on a shared network), which is coded as if it were a normal (l ...

and task distribution pattern. ; Publish–subscribe :Connects a set of publishers to a set of subscribers. This is a data distribution pattern. ;Push–pull (pipeline) :Connects nodes in a fan-out / fan-in pattern that can have multiple steps, and loops. This is a

parallel Parallel is a geometric term of location which may refer to: Computing * Parallel algorithm * Parallel computing * Parallel metaheuristic * Parallel (software), a UNIX utility for running programs in parallel * Parallel Sysplex, a cluster of ...

task distribution and collection pattern. ;Exclusive pair :Connects two sockets in an exclusive pair. (This is an advanced low-level pattern for specific use cases.) Each pattern defines a particular network topology. Request-reply defines a so-called "service bus", publish-subscribe defines a "data distribution tree", and push-pull defines "parallelised pipeline". All the patterns are deliberately designed in such a way as to be infinitely scalable and thus usable on Internet scale. Any message through the socket is treated as an opaque

blob Blob may refer to: Science Computing * Binary blob, in open source software, a non-free object file loaded into the kernel * Binary large object (BLOB), in computer database systems * A storage mechanism in the cloud computing platform M ...

of data. Delivery to a subscriber can be automatically filtered by the blob leading string. Available message transports include TCP, PGM (reliable multicast), inter-process communication ( IPC) and inter-thread communication (ITC). The ZeroMQ core library performs very well due to its internal threading model, and can outperform conventional TCP applications in terms of throughput by utilizing an automatic message batching technique. ZeroMQ implements ZMTP, the ZeroMQ Message Transfer Protocol. ZMTP defines rules for backward interoperability, extensible security mechanisms, command and message framing, connection metadata, and other transport-level functionality. A growing number of projects implement ZMTP directly as an alternative to using the full ZeroMQ implementations.

History

iMatix CEO

Pieter Hintjens Pieter Hintjens (3 December 1962 – 4 October 2016) was a Belgian software developer, author, and past president of the Foundation for a Free Information Infrastructure (FFII), an association that fights against software patents. In 2007, ...

registered the zeromq.org domain in May 2007 and started the ZeroMQ project together with Martin Sustrik, who was its architect and lead developer until December 2011. On March 30, 2010, Hintjens announced that iMatix (the original designer of

Advanced Message Queuing Protocol The Advanced Message Queuing Protocol (AMQP) is an open standard application layer protocol for message-oriented middleware. The defining features of AMQP are message orientation, queuing, routing (including point-to-point and publish-and-su ...

) would leave the AMQP workgroup and did not plan to support AMQP/1.0 in favor of the significantly simpler and faster ZeroMQ. In 2011,

CERN The European Organization for Nuclear Research, known as CERN (; ; ), is an intergovernmental organization that operates the largest particle physics laboratory in the world. Established in 1954, it is based in a northwestern suburb of Gene ...

was investigating ways to unify middleware solutions used to operate CERN accelerators. The CERN study compared two open source implementations of

CORBA The Common Object Request Broker Architecture (CORBA) is a standard defined by the Object Management Group (OMG) designed to facilitate the communication of systems that are deployed on diverse platforms. CORBA enables collaboration between sys ...

Ice Ice is water frozen into a solid state, typically forming at or below temperatures of 0 degrees Celsius or Depending on the presence of impurities such as particles of soil or bubbles of air, it can appear transparent or a more or less opaq ...

, Thrift, ZeroMQ, YAMI4, RTI, and

Qpid "Qpid" is the 94th episode of the syndicated American science fiction television series '' Star Trek: The Next Generation'', the 20th episode of the fourth season. Set in the 24th century, the series follows the adventures of the Starfleet cr ...

(AMQP) and scored ZeroMQ highest, in part for its versatility, including its easy adaptability to the

LynxOS The LynxOS RTOS is a Unix-like real-time operating system from Lynx Software Technologies (formerly "LynuxWorks"). Sometimes known as the Lynx Operating System, LynxOS features full POSIX conformance and, more recently, Linux compatibility. Ly ...

. At the start of 2012, two of the original developers forked ZeroMQ as Crossroads I/O. Martin Sustrik has started nanomsg, a rewrite of the ZeroMQ core library. In August 2012, Dongmin Yu announced his pure Java conversion of ZeroMQ, JeroMQ. This has inspired further full-native ports of ZeroMQ, such as NetMQ for C# and zmq.rs for Rust. In March 2013, Pieter Hintjens announced a new draft of the ZMTP wire-level protocol bringing extensible security mechanisms to ZeroMQ. Martin Hurton implemented the CurveZMQ authentication and encryption mechanism in the core library shortly afterwards.

Development process

The ZeroMQ community mostly uses the Collective Code Construction Contract (C4) as a development contract. C4 is inspired by

Wikipedia Wikipedia is a multilingual free online encyclopedia written and maintained by a community of volunteers, known as Wikipedians, through open collaboration and using a wiki-based editing system. Wikipedia is the largest and most-read refer ...

processes and

GitHub GitHub, Inc. () is an Internet hosting service for software development and version control using Git. It provides the distributed version control of Git plus access control, bug tracking, software feature requests, task management, continuous ...

's fork +

pull request In software development, distributed version control (also known as distributed revision control) is a form of version control in which the complete codebase, including its full history, is mirrored on every developer's computer. Compared to centr ...

model. It focuses on making it simpler for new contributors to participate and reducing dependency on older contributors.

Technology

History

Development process

See also

References

External links