azure service bus : under the hood

IoT day 2015

Azure Service Bus : under the hood

AMQP protocol fundamentalsPaolo Patierno

Microsoft MVP for Windows Embedded

@ppatierno

IoT day 2015

Sponsor

Who am I ? Contacts

•Senior Software Engineer (Leonardo Ricerche S.r.l.)

•Microsoft MVP for Windows Embedded

”... constantly moving between the devices and the cloud ...”

•«DotNetCampania» member• https://paolopatierno.wordpress.com

•«TinyCLR.it» member• http://www.tinyclr.it

•«Embedded101» board of director member• http://www.embedded101.com/Blogs/PaoloPatierno.aspx

•Linkedin• http://it.linkedin.com/in/paolopatierno

•Contacts• [twitter] @ppatierno

• [email] ppatierno@live.com

• [skype] paolopat80

Agenda

•IoT communication patterns

•Azure Service Bus intro …• Queues

• Topics/Subscriptions

• Event Hubs

•… under the cover : AMQP protocol• Introduction

• Architecture

• Communication

• How it fits the patterns

•Demo

IoT Communication Patterns

Telemetry

Information flows

from device to other

systems for

conveying status

changes in the device

Inquiries

Requests from

devices looking to

gather required

information or asking

to initiate activities

Commands

Commands from

other systems to a

device or a group of

devices to perform

specific activities

Notifications

Information flows from

other systems to a

device or a group for

conveying status

changes in the world

1:N 1:N

Azure Service Bus … Queues

•Competing Consumers pattern• all consumers read from same stream (queue)

•Message consumed by a single consumer

Azure Service Bus … Topics

•Publish/Subscribe pattern• each consumer reads from its subscription (a copy of message on related

topic)

•Message consumed by more subscribers (use filters)

Subs

Azure Service Bus … Event Hubs

•Partitioned Consumers pattern

Proprietary messaging protocols

•Difficult to port applications• Requires re-coding all applications

•Difficult to integrate• Application level bridges to move messages

and translate message formats

•Restricted platform support• Limited to whatever vendor provides

Advanced Message Queuing Protocol 1.0

•Open, standard messaging protocol• OASIS (since 2012/10) and ISO/IEC (since 2014/05)

• Enables cross-platform apps to be built using brokers, libraries and frameworks from different vendors

•Features• Efficient : binary connection-oriented protocol

• Reliable : “fire and forget” to reliable, “exactly once” delivery

• Portable data representation : cross-platform, full-fidelity exchange

• Flexible : client-client, client-broker and broker-broker topologies

• Broker model independent : no requirements on broker internals

Microsoft said …

“Microsoft congratulates the AMQP community on approval of AMQP version 1.0 as an OASIS Standard. As an open and interoperable messaging protocol that can scale from mobile clients to the cloud, AMQP has benefitted from the participation of technical experts from around the world, and the achievement of this important milestone will lead to continued growth in the AMQP ecosystem. We look forward to working with the community to promote AMQP-based interoperability and innovation.”

-- Scott Guthrie

AMQP 1.0 client libraries

Language Library

C# Service Bus .NET Client Library, AMQP.Net Lite

JavaApache Qpid Java Message Service (JMS) client

IIT SwiftMQ Java client

C Apache Qpid Proton-C

PHP Apache Qpid Proton-PHP

Python Apache Qpid Proton-Python

Ruby Apache Qpid Proton-Ruby

Perl Apache Qpid Proton-Perl

NodeJS Node AMQP 1.0

AMQP : containers and nodes

•architecture• wire protocol

• data types system with compact binary encoding

•container• client contains producer and/or consumer

• broker contains entities (ex. queues, topics/subscriptions, event hubs)

•node• producer sends messages

• consumer receives messages

• entities store and/or forward messages

AMQP : transport

client

producer

(consumer)

broker

entity

container containerconnection

session

link

node node

multiplexing frames on sessions and links

transport indipendent

open (max frame size, channel max, timeout)

AMQP : communication Open

•Open TCP connection

•Open ”connection”

•Begin ”session”

•Attach ”link”

Container Container

header AMQP / SASL handshake

open (max frame size, channel max, …)

begin (in/out window, handle max, …)

begin (in/out window, handle max, …)

attach (name, source, target, handle, …)

attach (name, source, target, handle, …)

open TCP

connection

open

«connection»

begin «session»

attach «link»

header AMQP / SASL handshake

AMQP : communication Send

•Send messages• to queue

• to topic

• to event hub

Producer Container

attach (name, source, target, handle, …)

attach (name, source, target, handle, …) attach «link»

flow (in/out window, link credit, …) flow control

transfer (delivery id/tag, settled, …)

disposition (first, last, settled, state, …)

sending

message

transfer (delivery id/tag, settled, …)

disposition (first, last, settled, state, …)

sending

messagestransfer (delivery id/tag, settled, …)

transfer (delivery id/tag, settled, …)

AMQP : communication Receive

•Receive messages• from queue

• from subscription

• from event hub

Consumer Container

attach (name, source, target, handle, …)

attach (name, source, target, handle, …) attach «link»

flow (in/out window, link credit, …) flow control

transfer (delivery id/tag, settled, …)

disposition (first, last, settled, state, …)

receiving

message

transfer (delivery id/tag, settled, …)

disposition (first, last, settled, state, …)

receiving

messagestransfer (delivery id/tag, settled, …)

transfer (delivery id/tag, settled, …)

end

AMQP : communication Close

•Detach ”link”

•End ”session”

•Close ”connection”

•Close TCP connection

Container Container

detach (handle, close, …)

end

close

close

detach «link»

end «session»

close

«connection»

detach (handle, close, …)

AMQP : Telemetry

•Data transfer

•Messages settled

Device Server

transfer (<resource>)

transfer (<resource>)

transfer (<resource>)

settlement (based on QoS)

settlement (based on QoS)

flow

in_queue

AMQP : Inquiry

•Correlation between inquiry

request and response

Device Server

transfer (<info>, replyTo, messageId)

transfer (<info>, correlationId = messageId)

settlement (based on QoS)

settlement (based on QoS)

in_queue out_queue

AMQP : Command

•Correlation between command

request and response

Device

transfer (<cmd>, replyTo, messageId)

transfer (<result>, correlationId = messageId)

settlement (based on QoS)

settlement (based on QoS)

Serverin_queue out_queue

AMQP : Notification

•Notification received

•Messages settled DeviceServer

transfer (<notifiy>)

settlement (based on QoS)

transfer (<notify>)

settlement (based on QoS)

flow

in_queue

AMQP : Claim Based Security (CBS) token

•Build a token based on publisher name, expire time, URI, key, …

•Send the token to the $cbs endpoint and specify a ReplyTo

•Receive status code of the request from the above ReplyTo

Device Server

transfer (<token>, replyTo, messageId)

transfer (<status code>, correlationId = messageId)

settlement (based on QoS)

settlement (based on QoS)

$cbs <replyTo>

AMQP : messages

•message• header

• annotations

• system properties (ex. correlationId, replyTo, TTL, …)

• custom/user properties

• «opaque» body (encoded as you want, ex. binary, XML, JSON, …)

•message metadata

•most times body empty, all values as properties

•filter on properties

•properties can be changed «on fly»

AMQP : main features

•messaging middleware• asynchronous : produce and consumer decoupled

• credit based to receive

+5

AMQP : main features

•more messaging patterns• load balancing and competing consumers (ex. on a queue)

• publish/subscribe (ex. on topic/subscription)

• partitioned consumers (ex. on event hubs)

• messages redirection to queues based on filters

• request/response w/ «correlation id» and «replyTo»

•session and transactional message transfer

AMQP : advantages

•efficient• binary connection-oriented

• ”flow control” credit based

• packet size 60 bytes

•reliable• Quality of Service (best effort, at least once, exactly once)

•security• SSL/TLS

• SASL (Simple Authentication and Security Layer)• decople authentication from application layer

Netduino 3 WiFi

•STM32 Cortex-M4

•2 MB dual-bank flash

•256 KB RAM

•WiFi module (TI CC 3100)

•Go-Bus ports

•Micro SD

•.Net Micro Framework

•Visual Studio 2013

•Azure Enabled (SSL/TLS)

IoT day 2015

Access to Service Bus with AMQP

References

•Microsoft Azure• Service Bus : http://azure.microsoft.com/en-us/services/service-bus/

• Event Hubs : http://azure.microsoft.com/en-us/services/event-hubs/

•AMQP • Official web site : http://www.amqp.org

• AMQP .Net Lite : http://amqpnetlite.codeplex.com/

• Azure SB Lite : http://azuresblite.codeplex.com/

• Azure SB Lite Examples : https://github.com/ppatierno/azuresblite-examples

• Apache Qpid: https://qpid.apache.org/