Opensource Messaging Queues?

SuperID asks: "I just attended a very long, mostly boring briefing smattered with zillions of animated color power point slides touting "messaging middleware" as the salvation of scalable architectures. While the buzzword density was extremely high ( "Data Mining" and "OLAP for the Information Warrior" *shudder* ) I can at least recognize a trend when it smacks me in the face. So, are there Opensource equivalents to products like IBM MQSeries or Microsoft Message Queing Server? Are there open standards that define how these types of servers operate? Maybe an Internet RFC?"

I wish...

[Stavr0]

I wish there was, that would spare us from forking $2000-$5000 per seat ...
On the bright side, IBM does have an MQ Client for Linux, the Server can't be that far off.
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Can you describe it more fully?

[Tyler Forge]

I may be working on just such a beast. Basically,
it's a server that hangs on a socket. Clients
connect and optionally identify themselves. A
client can send a message, via the server, to
any client which has identified itself. A client
can query the server for info. A client can
ask to snoop on one or more other clients or to
receive all messages of a certain type, or all
messages.

Is this what you mean by a message queue?

Re:Can you describe it more fully?

[bunyip]

IBM's MQ is a store-and-forward product. You put a message into a queue and it is guaranteed to be delivered, whether or not the target machine & program is currently operating. Queued messages are written to disk.

There are other options, non-protected queues, pub/sub, etc. The queue server can start programs when messages arrive in the queue, at certain thresholds. Messages can contain correlation ID information so that you can make a simple conversation over a one-way store-and-forward protocol.

Linux MOM

[Wabi]

I work for one of the "big 5" (or is it big 4 now?) consulting companies and just finished up a 6 month "study" on this type of middleware. The short answer to this question is, NO. There are no opensourced messaging middleware products currently available. As has already been mentioned, Linux is supported by a few existing commercial products:

* The MQSeries client for Linux: It's old (1997) and unsupported. I don't believe IBM currently has any plans to port the MQSeries server to Linux. Even if they do, it is likely to carry the same large ($2000-$5000) licensing costs of other Unix platforms.

* TIBCO Rendezvous: Tibco has full support for Linux in their Rendezvous product. Rendezvous is a publish/subscribe MOM product.

However, MOM products are typically used to integrate large backend legacy systems with newer systems and services. They allow you to have an OS/390 running nothing but SNA communicate with a Unix box running TCP/IP without having to learn all the "gory" low level programming details of each protocol (which usually aren't all that bad, they're just to complicated for folks who would rather write application logic :). Given that the vast majority of Linux (and *BSD) boxen run on IP networks, and that most open source developers are probably comfortable with network programming, it's not really a supprize to me that no one has found it necessary to write a general purpose open source MOM system.

Not that I would mind if someone did. In particular, an MQSeries server (or better yet, and MQSeries _compatible_ server) would be a big help in getting Linux into high end data centers.

Cheers,
Ian