Rabbit
Rabbit is a set of tools for building applications with RabbitMQ.
Installation
The package can be installed by adding rabbit
to your list of dependencies in mix.exs
:
def deps do
[
{:rabbit, "~> 0.4"}
]
end
Documentation
Please see HexDocs for additional documentation.
Connections
Create a connection module:
defmodule MyConnection do
use Rabbit.Connection
def start_link(opts \\ []) do
Rabbit.Connection.start_link(__MODULE__, opts, name: __MODULE__)
end
# Callbacks
@impl Rabbit.Connection
def init(_type, opts) do
# Perform runtime config
uri = System.get_env("RABBITMQ_URI") || "amqp://guest:guest@127.0.0.1:5672"
opts = Keyword.put(opts, :uri, uri)
{:ok, opts}
end
end
MyConnection.start_link()
Consumers
Create a consumer module:
defmodule MyConsumer do
use Rabbit.Consumer
def start_link(opts \\ []) do
Rabbit.Consumer.start_link(__MODULE__, opts, name: __MODULE__)
end
# Callbacks
@impl Rabbit.Consumer
def init(_type, opts) do
# Perform runtime config
{:ok, opts}
end
@impl Rabbit.Consumer
def handle_setup(channel, queue) do
# Perform any exchange or queue setup
AMQP.Queue.declare(channel, queue)
:ok
end
@impl Rabbit.Consumer
def handle_message(message) do
# Handle message consumption
IO.inspect(message.payload)
{:ack, message}
end
@impl Rabbit.Consumer
def handle_error(message) do
# Handle message errors
{:nack, message}
end
end
MyConsumer.start_link(connection: MyConnection, queue: "my_queue", prefetch_count: 10)
Consumer Supervisors
Create a consumer supervisor module:
defmodule MyConsumerSupervisor do
use Rabbit.ConsumerSupervisor
def start_link(consumers \\ []) do
Rabbit.ConsumerSupervisor.start_link(__MODULE__, consumers, name: __MODULE__)
end
# Callbacks
@impl Rabbit.ConsumerSupervisor
def init(:consumer_supervisor, _consumers) do
# Perform runtime config for the consumer supervisor
consumers = [
[connection: MyConnection, queue: "my_queue1", prefetch_count: 5],
[connection: MyConnection, queue: "my_queue2", prefetch_count: 10],
]
{:ok, consumers}
end
def init(:consumer, opts) do
# Perform runtime config per consumer
{:ok, opts}
end
@impl Rabbit.ConsumerSupervisor
def handle_setup(channel, queue) do
# Perform any exchange or queue setup per consumer
AMQP.Queue.declare(channel, queue)
:ok
end
@impl Rabbit.ConsumerSupervisor
def handle_message(message) do
# Handle message consumption per consumer
IO.inspect(message.payload)
{:ack, message}
end
@impl Rabbit.ConsumerSupervisor
def handle_error(message) do
# Handle message errors per consumer
{:nack, message}
end
end
MyConsumerSupervisor.start_link()
Producers
Create a producer module:
defmodule MyProducer do
use Rabbit.Producer
def start_link(opts \\ []) do
Rabbit.Producer.start_link(__MODULE__, opts, name: __MODULE__)
end
# Callbacks
@impl Rabbit.Producer
def init(:producer, opts) do
# Perform runtime config
{:ok, opts}
end
end
MyProducer.start_link(connection: MyConnection)
Rabbit.Producer.publish(MyProducer, "", "my_queue", "hello")
Initializers
Create an initializer module:
defmodule MyInitializer do
use Rabbit.Initializer
def start_link(opts \\ []) do
Rabbit.Initializer.start_link(__MODULE__, opts, name: __MODULE__)
end
# Callbacks
@impl Rabbit.Initializer
def init(:initializer, opts) do
# Perform runtime config
{:ok, opts}
end
end
MyInitializer.start_link(
connection: MyConnection,
queues: [
[name: "my_queue_1"],
[name: "my_queue_2", durable: true],
],
exchanges: [
[name: "my_exchange_1"],
[name: "my_exchange_2", type: :fanout, durable: true],
],
bindings: [
[type: :queue, source: "my_exchange_1", destination: "my_queue_1", routing_key: "my_key"],
[type: :exchange, source: "my_exchange_2", destination: "my_exchange_1"]
]
)