Dissecting the rabbit: RabbitMQ Internal Architecture
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The document presents an in-depth analysis of RabbitMQ's internal architecture and functionalities, including its messaging system, process management, and extensibility features. It explains concepts like message storage, supervision trees, and various RabbitMQ behaviors, as well as providing examples of Erlang code related to its operation. Additionally, it discusses practical implementations and configurations, highlighting RabbitMQ's adaptability for various user needs within different programming environments.
![rabbit_client_sup.erl
-module(rabbit_client_sup).!
!
-behaviour(supervisor2).!
!
-export([start_link/1, start_link/2, start_link_worker/2]).!
!
-export([init/1]).!
!
-include("rabbit.hrl").](https://image.slidesharecdn.com/dissectingtherabbit-131029005316-phpapp02/85/Dissecting-the-rabbit-RabbitMQ-Internal-Architecture-44-320.jpg)
![rabbit_client_sup.erl
start_link(Callback) ->!
supervisor2:start_link(?MODULE, Callback).!
!
start_link(SupName, Callback) ->!
supervisor2:start_link(SupName, ?MODULE, Callback).!
!
start_link_worker(SupName, Callback) ->!
supervisor2:start_link(SupName, ?MODULE, {Callback, worker}).!
!
init({M,F,A}) ->!
{ok, {{simple_one_for_one, 0, 1},!
[{client, {M,F,A}, temporary, infinity, supervisor, [M]}]}};!
init({{M,F,A}, worker}) ->!
{ok, {{simple_one_for_one, 0, 1},!
[{client, {M,F,A}, temporary, ?MAX_WAIT, worker, [M]}]}}.](https://image.slidesharecdn.com/dissectingtherabbit-131029005316-phpapp02/85/Dissecting-the-rabbit-RabbitMQ-Internal-Architecture-45-320.jpg)
![rabbit_client_sup
init({M,F,A}) ->!
{ok, {{simple_one_for_one, 0, 1},!
[{client, {M,F,A}, temporary, !
! ! ! !
infinity, supervisor, [M]}]}};](https://image.slidesharecdn.com/dissectingtherabbit-131029005316-phpapp02/85/Dissecting-the-rabbit-RabbitMQ-Internal-Architecture-48-320.jpg)
![Child Specification
child_spec() = {Id,StartFunc,Restart,Shutdown,Type,Modules}!
Id = term()!
StartFunc = {M,F,A}!
M = F = atom()!
A = [term()]!
Restart = permanent | transient | temporary!
Shutdown = brutal_kill | int()>0 | infinity!
Type = worker | supervisor!
Modules = [Module] | dynamic!
Module = atom()](https://image.slidesharecdn.com/dissectingtherabbit-131029005316-phpapp02/85/Dissecting-the-rabbit-RabbitMQ-Internal-Architecture-50-320.jpg)
![rabbit_client_sup
init({M,F,A}) ->!
{ok, {{simple_one_for_one, 0, 1},!
[{client, {M,F,A}, temporary, !
! ! ! !
infinity, supervisor, [M]}]}};](https://image.slidesharecdn.com/dissectingtherabbit-131029005316-phpapp02/85/Dissecting-the-rabbit-RabbitMQ-Internal-Architecture-51-320.jpg)
![Intermezzo: pattern matching
check_user_id_header(#'P_basic'{user_id = undefined}, _) ->!
ok;!
check_user_id_header(#'P_basic'{user_id = Username},!
#ch{user = #user{username = Username}}) ->!
ok;!
check_user_id_header(#'P_basic'{user_id = Claimed},!
#ch{user = #user{username = Actual,!
tags
= Tags}}) ->!
case lists:member(impersonator, Tags) of!
true -> ok;!
false -> precondition_failed(!
"user_id property set to '~s' but authenticated user was "!
"'~s'", [Claimed, Actual])!
end.
http://videlalvaro.github.io/2013/09/rabbitmq-validating-user-ids-with-erlang-pattern-matching.html](https://image.slidesharecdn.com/dissectingtherabbit-131029005316-phpapp02/85/Dissecting-the-rabbit-RabbitMQ-Internal-Architecture-62-320.jpg)
![rabbit_exchange_type
-module(rabbit_exchange_type).!
!
-callback description() -> [proplists:property()].!
!
-callback serialise_events() -> boolean().!
!
-callback route(rabbit_types:exchange(), rabbit_types:delivery()) ->!
rabbit_router:match_result().!
!
-callback validate(rabbit_types:exchange()) -> 'ok'.!
!
-callback validate_binding(rabbit_types:exchange(), rabbit_types:binding()) ->!
rabbit_types:ok_or_error({'binding_invalid', string(), [any()]}).](https://image.slidesharecdn.com/dissectingtherabbit-131029005316-phpapp02/85/Dissecting-the-rabbit-RabbitMQ-Internal-Architecture-89-320.jpg)
![RabbitMQ Behaviours
•
•
•
rabbit_auth_backend
rabbit_msg_store_index
rabbit_backing_queue
(config)
(config)
(config)
[{rabbit,!
[{auth_backends, [rabbit_auth_backend_http, !
rabbit_auth_backend_internal]}]!
}].](https://image.slidesharecdn.com/dissectingtherabbit-131029005316-phpapp02/85/Dissecting-the-rabbit-RabbitMQ-Internal-Architecture-92-320.jpg)
![RabbitMQ Behaviours
•
•
•
•
•
•
•
rabbit_auth_mechanism
rabbit_exchange_decorator
rabbit_exchange_type
rabbit_mirror_queue_mode
rabbit_policy_validator
rabbit_queue_decorator
rabbit_runtime_parameter
(registry)
(registry)
(registry)
(registry)
(registry)
(registry)
(registry)
-rabbit_boot_step({?MODULE,!
[{description, "exchange type direct"},!
{mfa,
{rabbit_registry, register,!
[exchange, <<"direct">>, ?MODULE]}},!
{requires,
rabbit_registry},!
{enables,
kernel_ready}]}).](https://image.slidesharecdn.com/dissectingtherabbit-131029005316-phpapp02/85/Dissecting-the-rabbit-RabbitMQ-Internal-Architecture-94-320.jpg)
![RabbitMQ Federation Plugin
-module(rabbit_federation_queue).!
!
-rabbit_boot_step({?MODULE,!
[{description, "federation queue decorator"},!
{mfa, {rabbit_registry, register,!
[queue_decorator, <<"federation">>, ?MODULE]}},!
{requires, rabbit_registry},!
{enables, recovery}]}).!
!
-behaviour(rabbit_queue_decorator).](https://image.slidesharecdn.com/dissectingtherabbit-131029005316-phpapp02/85/Dissecting-the-rabbit-RabbitMQ-Internal-Architecture-98-320.jpg)
![RabbitMQ Federation Plugin
-module(rabbit_federation_exchange).!
!
-rabbit_boot_step({?MODULE,!
[{description, "federation exchange decorator"},!
{mfa, {rabbit_registry, register,!
[exchange_decorator, <<"federation">>, ?MODULE]}},!
{requires, rabbit_registry},!
{enables, recovery}]}).!
!
-behaviour(rabbit_exchange_decorator).](https://image.slidesharecdn.com/dissectingtherabbit-131029005316-phpapp02/85/Dissecting-the-rabbit-RabbitMQ-Internal-Architecture-99-320.jpg)
Dissecting the rabbit: RabbitMQ Internal Architecture
- 1. Dissecting the Rabbit: RabbitMQ Internal Architecture Alvaro Videla - RabbitMQ
- 2. Alvaro Videla • • • • • Developer Advocate at Pivotal / RabbitMQ! Co-Author of RabbitMQ in Action! Creator of the RabbitMQ Simulator! Blogs about RabbitMQ Internals: http://videlalvaro.github.io/internals.html! @old_sound | [email protected] github.com/videlalvaro
- 3. About Me Co-authored! ! RabbitMQ in Action! http://bit.ly/rabbitmq
- 4. Agenda • Intro to RabbitMQ • Dive into RabbitMQ Internals • A day in the life of a message • RabbitMQ message store • RabbitMQ behaviours and extensibility
- 6. RabbitMQ
- 7. RabbitMQ
- 8. RabbitMQ • Multi Protocol Messaging Server
- 9. RabbitMQ • Multi Protocol Messaging Server! • Open Source (MPL)
- 10. RabbitMQ • Multi Protocol Messaging Server! • Open Source (MPL)! • Polyglot
- 11. RabbitMQ • Multi Protocol Messaging Server! • Open Source (MPL)! • Polyglot! • Written in Erlang/OTP
- 13. Polyglot
- 14. Polyglot
- 15. Polyglot • Java
- 17. Polyglot • Java! • node.js! • Erlang
- 18. Polyglot • Java! • node.js! • Erlang! • PHP
- 19. Polyglot • Java! • node.js! • Erlang! • PHP! • Ruby
- 20. Polyglot • Java! • node.js! • Erlang! • PHP! • Ruby! • .Net
- 21. Polyglot • Java! • node.js! • Erlang! • PHP! • Ruby! • .Net! • Haskell
- 23. Some users of RabbitMQ
- 24. Some users of RabbitMQ • Instagram
- 25. Some users of RabbitMQ • • Instagram! Indeed.com
- 26. Some users of RabbitMQ • • • Instagram! Indeed.com! MailboxApp
- 27. Some users of RabbitMQ • • • • Instagram! Indeed.com! MailboxApp! Mercado Libre
- 28. Some users of RabbitMQ • • • • • Instagram! Indeed.com! MailboxApp! Mercado Libre! NHS
- 29. Some users of RabbitMQ • • • • • • Instagram! Indeed.com! MailboxApp! Mercado Libre! NHS! Mozilla
- 30. http://www.rabbitmq.com/download.html Unix - Mac - Windows
- 31. Messaging with RabbitMQ A demo with the RabbitMQ Simulator https://github.com/RabbitMQSimulator/RabbitMQSimulator
- 35. A day in the life of a message
- 36. A day in the life of a message
- 37. A day in the life of a message $conn = new AMQPConnection(HOST, PORT, USER, PASS, VHOST);! $ch = $conn->channel();! ! $ch->queue_declare($queue, false, true, false, false);! ! $ch->exchange_declare($exchange, 'direct', false, true, false);! ! $ch->queue_bind($queue, $exchange);! ! $msg_body = implode(' ', array_slice($argv, 1));! $msg = new AMQPMessage($msg_body, array('delivery_mode' => 2));! ! $ch->basic_publish($msg, $exchange);
- 38. What happens here? $conn = new AMQPConnection(HOST, PORT, USER, PASS, VHOST);! $ch = $conn->channel();
- 40. Erlang
- 41. Erlang App • Processes (probably thousands) • They communicate sending messages • Each process has a message queue (don’t confuse with RabbitMQ queues) • Virtual Machine has preemptive scheduler
- 43. Erlang code structure • Modules • Functions • Function Arity • Arguments M, F, A = Module, Function, Arguments
- 45. rabbit_client_sup.erl start_link(Callback) ->! supervisor2:start_link(?MODULE, Callback).! ! start_link(SupName, Callback) ->! supervisor2:start_link(SupName, ?MODULE, Callback).! ! start_link_worker(SupName, Callback) ->! supervisor2:start_link(SupName, ?MODULE, {Callback, worker}).! ! init({M,F,A}) ->! {ok, {{simple_one_for_one, 0, 1},! [{client, {M,F,A}, temporary, infinity, supervisor, [M]}]}};! init({{M,F,A}, worker}) ->! {ok, {{simple_one_for_one, 0, 1},! [{client, {M,F,A}, temporary, ?MAX_WAIT, worker, [M]}]}}.
- 47. Supervision tree • Worker Processes • Supervisor Processes • Supervision tree as a hierarchical arrangement of processes http://www.erlang.org/doc/man/supervisor.html
- 48. rabbit_client_sup init({M,F,A}) ->! {ok, {{simple_one_for_one, 0, 1},! [{client, {M,F,A}, temporary, ! ! ! ! ! infinity, supervisor, [M]}]}};
- 49. Child Spec - restart strategies • one_for_one: only restart failing process • one_for_all: restart failing process and all siblings • simple_one_for_one: simplified version of one_for_one • MaxR: maximum restarts allowed • MaxT: in MaxT seconds
- 50. Child Specification child_spec() = {Id,StartFunc,Restart,Shutdown,Type,Modules}! Id = term()! StartFunc = {M,F,A}! M = F = atom()! A = [term()]! Restart = permanent | transient | temporary! Shutdown = brutal_kill | int()>0 | infinity! Type = worker | supervisor! Modules = [Module] | dynamic! Module = atom()
- 51. rabbit_client_sup init({M,F,A}) ->! {ok, {{simple_one_for_one, 0, 1},! [{client, {M,F,A}, temporary, ! ! ! ! ! infinity, supervisor, [M]}]}};
- 52. Child Spec - restart • permanent: should always be restarted • temporary: should never be restarted • transient: should only be restarted if terminated abnormally
- 53. Child Spec - shutdown • brutal_kill: child is terminated immediately. • timeout in seconds: supervisor waits for timeout before terminating children. • infinity: give enough timeout to children to shutdown its own supervision tree.
- 59. A day in the life of a message
- 60. A day in the life of a message
- 61. A day in the life of a message
- 62. Intermezzo: pattern matching check_user_id_header(#'P_basic'{user_id = undefined}, _) ->! ok;! check_user_id_header(#'P_basic'{user_id = Username},! #ch{user = #user{username = Username}}) ->! ok;! check_user_id_header(#'P_basic'{user_id = Claimed},! #ch{user = #user{username = Actual,! tags = Tags}}) ->! case lists:member(impersonator, Tags) of! true -> ok;! false -> precondition_failed(! "user_id property set to '~s' but authenticated user was "! "'~s'", [Claimed, Actual])! end. http://videlalvaro.github.io/2013/09/rabbitmq-validating-user-ids-with-erlang-pattern-matching.html
- 64. A day in the life of a message
- 65. A day in the life of a message
- 66. A day in the life of a message We have a list of queues where the channel will deliver the messages
- 67. A day in the life of a message
- 68. A day in the life of a message If consumer ready
- 69. RabbitMQ Message Store • Made specifically for messaging • Keeps messages in memory and (sometimes) on disk • Bounded by disk size • per node message store (transient, persistent) • per queue “queue index”
- 70. RabbitMQ Message Store • Message written to disk when: • Message published as persistent (delivery_mode = 2) • Memory pressure
- 71. Read More Here:
- 72. Read More Here: Why a custom message store? ! http://www.rabbitmq.com/blog/2011/01/20/rabbitmq-backing-stores-databases-and-disks/
- 73. Read More Here: Why a custom message store? ! http://www.rabbitmq.com/blog/2011/01/20/rabbitmq-backing-stores-databases-and-disks/ How the message store compacts files ! http://hg.rabbitmq.com/rabbitmq-server/file/56d190fd4ea3/src/rabbit_msg_store.erl#l181
- 74. Read More Here: Why a custom message store? ! http://www.rabbitmq.com/blog/2011/01/20/rabbitmq-backing-stores-databases-and-disks/ How the message store compacts files ! http://hg.rabbitmq.com/rabbitmq-server/file/56d190fd4ea3/src/rabbit_msg_store.erl#l181 How the message store reacts to memory pressure ! http://hg.rabbitmq.com/rabbitmq-server/file/56d190fd4ea3/src/rabbit_variable_queue.erl#l35
- 75. Credit Flow
- 76. Prevent processes from overflowing each other’s mailboxes
- 79. Process A sends messages to B
- 80. Process will • Grant more credit • Block other processes • Delay granting credits
- 83. RabbitMQ Behaviours • Add a common interface for different components
- 84. RabbitMQ Behaviours • Add a common interface for different components • Exchanges
- 85. RabbitMQ Behaviours • Add a common interface for different components • Exchanges • Queues
- 86. RabbitMQ Behaviours • Add a common interface for different components • Exchanges • Queues • Decorators
- 87. RabbitMQ Behaviours • Add a common interface for different components • Exchanges • Queues • Decorators • Authentication methods
- 88. RabbitMQ Behaviours • Add a common interface for different components • • Queues • Decorators • • Exchanges Authentication methods Add extensibility
- 89. rabbit_exchange_type -module(rabbit_exchange_type).! ! -callback description() -> [proplists:property()].! ! -callback serialise_events() -> boolean().! ! -callback route(rabbit_types:exchange(), rabbit_types:delivery()) ->! rabbit_router:match_result().! ! -callback validate(rabbit_types:exchange()) -> 'ok'.! ! -callback validate_binding(rabbit_types:exchange(), rabbit_types:binding()) ->! rabbit_types:ok_or_error({'binding_invalid', string(), [any()]}).
- 90. rabbit_exchange_type • You can add your own exchange type via plugins • consistent hash exchange • random exchange • recent history exchange • riak exchange
- 92. RabbitMQ Behaviours • • • rabbit_auth_backend rabbit_msg_store_index rabbit_backing_queue (config) (config) (config) [{rabbit,! [{auth_backends, [rabbit_auth_backend_http, ! rabbit_auth_backend_internal]}]! }].
- 94. RabbitMQ Behaviours • • • • • • • rabbit_auth_mechanism rabbit_exchange_decorator rabbit_exchange_type rabbit_mirror_queue_mode rabbit_policy_validator rabbit_queue_decorator rabbit_runtime_parameter (registry) (registry) (registry) (registry) (registry) (registry) (registry) -rabbit_boot_step({?MODULE,! [{description, "exchange type direct"},! {mfa, {rabbit_registry, register,! [exchange, <<"direct">>, ?MODULE]}},! {requires, rabbit_registry},! {enables, kernel_ready}]}).
- 95. RabbitMQ Federation Plugin • Message replication across WANs • Uses an exchange decorator • Uses a queue decorator • Uses parameters • Uses policies
- 96. RabbitMQ Federation Plugin rabbitmqctl set_parameter federation-upstream my-upstream ! '{"uri":"amqp://server-name","expires":3600000}'
- 97. RabbitMQ Federation Plugin rabbitmqctl set_parameter federation-upstream my-upstream ! '{"uri":"amqp://server-name","expires":3600000}' rabbitmqctl set_policy federate-me "^amq." '{"federation-upstreamset":"all"}'
- 98. RabbitMQ Federation Plugin -module(rabbit_federation_queue).! ! -rabbit_boot_step({?MODULE,! [{description, "federation queue decorator"},! {mfa, {rabbit_registry, register,! [queue_decorator, <<"federation">>, ?MODULE]}},! {requires, rabbit_registry},! {enables, recovery}]}).! ! -behaviour(rabbit_queue_decorator).
- 99. RabbitMQ Federation Plugin -module(rabbit_federation_exchange).! ! -rabbit_boot_step({?MODULE,! [{description, "federation exchange decorator"},! {mfa, {rabbit_registry, register,! [exchange_decorator, <<"federation">>, ?MODULE]}},! {requires, rabbit_registry},! {enables, recovery}]}).! ! -behaviour(rabbit_exchange_decorator).
- 101. Read More Here: Making sure the user provided the right behaviour: ! http://videlalvaro.github.io/2013/09/rabbitmq-internals-validating-erlang-behaviours.html How RabbitMQ prevents arbitrary code execution: ! http://videlalvaro.github.io/2013/09/rabbitmq-sanitzing-user-input-in-erlang.html RabbitMQ Boot Step System: ! https://github.com/videlalvaro/rabbit-internals/blob/master/rabbit_boot_process.md
- 102. RabbitMQ uses Erlang’s features to be robust, fault tolerant and very extensible
- 103. Go grab the source code! http://hg.rabbitmq.com/rabbitmq-server/
- 104. Questions?
- 105. Thanks Alvaro Videla - @old_sound