package amqp-client

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_spec and Amqp_framing modules as well as a high level interface though module Amqp.

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 replying 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.

Documentation for the API (async version).

Build infrastructure

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.

To build the library

make build

make install will install Lwt and Async depending on availability of Async / Lwt.

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

Example

open 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 ()

Compile with:

$ 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/tests