Quick browsed the doc this morning. Very happy to see this. Some novelty here I think. The Pub/Sub vs. say strict Actor Peer-To-Peer seems more flexible. Typed Endpoints and Handlers. Yea!!
Looks like I can throw out some really half-baked code that addresses similar functionality as Marketplace and does a poor job of doing so and use Marketplace. What is the general assumption, if any, regarding message delivery guarantees? Guaranteed, Once-And-Only-Once, At-Most-Once. And Message Ordering. Say between 2 physical node Ground-VMs across a network? Node 1 - Process A - sends M1 - sends M2 ----> Node 2 - Process B always consumes M1 before M2? Also rather curious on details of Marketplaces' approach to "Let-It-Fail" semantics and Nanny monitoring / restarting of processes. And it's in Typed Racket too. Double plus good. On Wed, May 29, 2013 at 5:47 PM, Sam Tobin-Hochstadt <sa...@ccs.neu.edu>wrote: > We are happy to announce the release of Marketplace, a new programming > language for building functional network programs. Marketplace combines > two fundamental ideas in a new way: nested virtual machines and > publish/subscribe messaging. Nesting allows programs to isolate > processes and to delimit conversations. While publish/subscribe generalizes > point-to-point and broadcast messaging, it smoothly turns the appearance > and disappearance of participants and resources into _presence_ and > _absence_ messages. Such messages make it particularly easy to start and > stop services and to manage resources based on demand. > > Here is a simple TCP echo server written in Marketplace: > > #lang marketplace > > (endpoint #:subscriber (tcp-channel ? (tcp-listener 5999) ?) > #:conversation (tcp-channel from to _) > #:on-presence (spawn #:child (echoer from to))) > > ;; echoer: TcpAddress TcpAddress -> Transition > (define (echoer from to) > (transition stateless > (endpoint #:subscriber (tcp-channel from to ?) > #:on-absence (quit) > [(tcp-channel _ _ data) > (send-message (tcp-channel to from data))]))) > > The initial `endpoint` subscribes to TCP messages on port 5999. When a > conversational partner appears, the endpoint spawns a new process that > runs an > `echoer` process. The latter is stateless and subscribes to TCP > messages. When it gets messages with payload `data`, it sends them back > out with the opposite addressing; when the TCP conversation disappears, it > quits. > > Thus far, we have built several real systems using Marketplace: a > DNS server, a DNS proxy, and an SSH server. The DNS proxy has handled > DNS traffic for ourselves and other members of our lab for the last > several months. > > You can read an overview along with detailed documentation for > Marketplace at http://tonyg.github.io/marketplace/ . > > To get the sources for Marketplace as well as the applications > point your browser to https://github.com/tonyg/marketplace . > > Enjoy! > > Tony Garnock-Jones > Sam Tobin-Hochstadt > Matthias Felleisen > ____________________ > Racket Users list: > http://lists.racket-lang.org/users >
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