OCaml client library for AMQP
Amqp-client is a AMQP client library written in pure OCaml. The library implements AMQP protocol version 0.9.1 as well as RabbitMQ-specific extensions. It supports both Core Async and Lwt threading models.
Amqp-client is tested extensively against RabbitMQ, but should work with any AMQP server.
The library exposes low level protocol handling though
Amqp_framing modules as well as a high level interface
The high level interface exposes usage patterns such as
- create queue
- consume from a queue
- post message to a queue
- create exchange
- bind a queue to an exchange
- post message to an exchange
- RPC client / server
The library requires all resources to be explicitly allocated to avoid crashes because a service is relying on other services to allocate AMQP resources (exchanges, queues etc.).
Channels and consumers are tagged with an id, host name, pid etc. to ease tracing on AMQP level.
The system is not functorized over an abstraction to the threading model. Instead the build system chooses which threading model abstraction to be used and stacially compiles it in. This has the advantage that files do not need to carry functor boilerplate
The disadvantage is that it does not allow users to supply their own threading model implementation.
It is recommended to install the package though opam. You should choose the package matching the concurrency library that your application will use
For Janestreet async:
opam install amqp-client-async
For Ocsigen Lwt:
opam install amqp-client-lwt
To build the library
make install will install both Lwt and Async versions.
Using the library
To compile using Async do:
ocamlfind ocamlopt -thread -package amqp-client-async myprog.ml
To compile using the Lwt version of the library do:
ocamlfind ocamlopt -thread -package amqp-client-lwt myprog.ml
open Async open Amqp_client_async let host = "localhost" let run () = Amqp.Connection.connect ~id:"MyConnection" host >>= fun connection -> Amqp.Connection.open_channel ~id:"MyChannel" Amqp.Channel.no_confirm connection >>= fun channel -> Amqp.Queue.declare channel "MyQueue" >>= fun queue -> Amqp.Queue.publish channel queue (Amqp.Message.make "My Message Payload") >>= function `Ok -> Amqp.Channel.close channel >>= fun () -> Amqp.Connection.close connection >>= fun () -> Shutdown.shutdown 0; return () let _ = don't_wait_for (run ()); Scheduler.go ()
$ ocamlfind ocamlopt -thread -package amqp-client-async amqp_example.ml -linkpkg -o amqp_example
More examples are available here: https://github.com/andersfugmann/amqp-client/tree/master/examples