Carrot v1.1.0 Carrot.ConnectionManager View Source

AMQP Connection Manager.

This module is intended to be used in the context of a supervision tree. It provides a process that will manage a connection to an AMQP server, provides mechanism for configurable exponential backoff, and connection retry.

Link to this section Summary

Types

backoff()

connection_option()

connection_options()

Functions

child_spec(arg)

Returns a specification to start this module under a supervisor

open_channel(server, timeout \\ 5000)

Opens a channel on the managed connection

start_link(config, opts \\ [])

Starts a connection manager process linked to the current process

Link to this section Types

backoff()

backoff() :: [min: pos_integer(), max: pos_integer()]

connection_option()

connection_option() ::
  {:username, String.t()}
  | {:password, String.t()}
  | {:virtual_host, String.t()}
  | {:host, String.t()}
  | {:port, pos_integer()}
  | {:channel_max, pos_integer()}
  | {:frame_max, pos_integer()}
  | {:heartbeat, pos_integer()}
  | {:connection_timeout, pos_integer()}
  | {:backoff, backoff()}
  | {:ssl_options, [:ssl.ssl_option()]}
  | {:client_properties, [...]}
  | {:socket_options, [:gen_tcp.option()]}
  | {:url, String.t()}

connection_options()

connection_options() :: [connection_option()]

Link to this section Functions

child_spec(arg)

Returns a specification to start this module under a supervisor.

See Supervisor.

open_channel(server, timeout \\ 5000)

open_channel(GenServer.server(), pos_integer()) ::
  {:ok, AMQP.Channel.t()} | {:error, any()}

Opens a channel on the managed connection.

Examples

# Healthy connection

{:ok, pid} = Carrot.ConnectionManager.start_link([...])
{:ok, chan} = Carrot.ConnectionManager.open_channel(pid)

# Disconnected

{:error, :disconnected} = Carrot.ConnectionManager.open_channel(pid)

start_link(config, opts \\ [])

start_link(connection_options(), GenServer.options()) :: GenServer.on_start()

Starts a connection manager process linked to the current process.

This is intended to be called from a supervision tree.

Connection Options

:username - The name of a user registered with the broker (defaults to “guest”);
:password - The password of user (defaults to “guest”);
:virtual_host - The name of a virtual host in the broker (defaults to “/“);
:host - The hostname of the broker (defaults to “localhost”);
:port - The port the broker is listening on (defaults to 5672);
:channel_max - The channel_max handshake parameter (defaults to 0);
:frame_max - The frame_max handshake parameter (defaults to 0);
:heartbeat - The hearbeat interval in seconds (defaults to 10);
:connection_timeout - The connection timeout in milliseconds (defaults to 60000);
:ssl_options - Enable SSL by setting the location to cert files (defaults to none);
:client_properties - A list of extra client properties to be sent to the server, defaults to [];
:socket_options - Extra socket options. These are appended to the default options. See http://www.erlang.org/doc/man/inet.html#setopts-2 and http://www.erlang.org/doc/man/gen_tcp.html#connect-4 for descriptions of the available options.
:url - The AMQP URI used to connect to the broker. If specified, it overrides all other connection options. See https://www.rabbitmq.com/uri-spec.html for more details on the RabbitMQ URI Specification

Enabling SSL

To enable SSL, supply the following in the ssl_options field:

cacertfile - Specifies the certificates of the root Certificate Authorities that we wish to implicitly trust;
certfile - The client’s own certificate in PEM format;
keyfile - The client’s private key in PEM format;