The document provides an overview of Azure Service Bus messaging capabilities. It recaps messaging patterns and scenarios. It describes the key components of Azure Service Bus including namespaces, queues, topics, and subscriptions. It covers sending and receiving messages with code examples and considerations around retries, duplicate detection, and large messages. Advanced features like sessions, auto-forwarding, and scheduled delivery are also mentioned. The presentation includes several demos of queues, topics, subscriptions, and sessions.

1. Azure Messaging Services #2
RIYADH 8
27 April 2019
Microsoft Riyadh

2. Amr Badawy
Technical Consultant

3. Agenda
 Messaging #1 Recap
 Azure Service Bus
 Queue
 Topic / Subscription
 Advanced Features
 A lot of Demos 
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4. 4
Messaging #1 Recap

5. Messaging in our Life
• Direct Communication
• Async two-way communication
 Filtering | Chaining | Expiration
 Ordering | Forwarding | Scheduling
 Dead-lettering | Batching | Security
 Mobile Apps
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Message Queuing Essentials
Recap

6. 6
Key Messaging Patterns (Basic)
One-way messagingFire-and-Forget Async two-way communication
Publish-Subscribe Broadcast messaging
Request-Response
Recap

7. 7
Asyn Messaging | Scenarios
• Decoupling workloads » decouple the logic that generates work from that logic that performs the work.
• Temporal decoupling » sender and receiver do not have to be running at the same time.
• Load balancing » distribute processing across servers and improve throughput
• Senders may post a large number of requests to a queue that is serviced by many receivers.
• Receivers can run on different servers to spread the load.
• Receivers can be added/removed dynamically to scale out/in (autoscaling) » Improve Scalability
• Load leveling » [Queue-Based Load Leveling pattern]
• Heavy load from senders >> increasing receivers to handle this work could overwhelm the system.
• acts as a buffer, and receivers work without stressing the system.
• minimize the impact of peaks
• Cross-platform integration » senders and receivers agree on a common format for messages and their contents.
• Deferred processing »
• Reliable messaging »
• The sender is not blocked unless it loses connectivity with the queue.
• message can wait until a destination component is ready to process
Recap

8. Misc.| Messaging
Terms
• Publisher / Sender / Producer » push / send
• Subscriber / Receiver / Consumer / Listener » pull /receive / retrieve
• MoM - Message-oriented Middleware / Message Queuing / Messaging
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Examples
• Book a ticket ( Booking Service )
1. Change state in DB
2. Notify Event Owner
3. Create an invoice a PDF
4. Send a confirmation email (invoice attached)
• Picture Resize
• Pushing a tweet :: How twitter write new tweet for followers
• Notification Service >> send many emails
• Logging service >> keep in buffer and then write to DB
• RFID Reader

9. 9
Azure Messaging Services

10. 10

11. 11
Azure Service Bus
Multi-tenant cloud messaging service & simple hybrid integration
Fully managed enterprise integration Message Broker

12. Azure Service Bus | Components
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 Namespace: scoping container for all messaging entities »
1. Queue
2. Topic & Subscription
Recap
 Managing:
1. Portal » less features
2. Code
3. PowerShell
4. Azure Resource Manager
5. Http/Rest

13. Azure Service Bus | .NET SDK
13
• First Release at Aug-2017
• .NET Standard ( Core & Full Framework)
• AMQP
• Open Source & Fully tested » GitHub
• Only Message Broker
• Microsoft.Azure.ServiceBus
• Message
Recap
• First Release at May-2011
• Only Full Framework
• Legacy SBMP by default
• Not Open Source
• Message Broker & EventHub and Relay
• Microsoft.ServiceBus.Messaging
• BrokeredMessage

14. 14
Service Bus | Queue

15. Azure Service Bus | Entity Props.
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16. Azure Service Bus | Portal
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17. Azure Service Bus | Explorer
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18. Azure Service Bus | Code Mgmt.
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 Queue, Topic , Subscription:
 Create
 Delete
 Update
 Get
 Exists
 Queue, Subscription:
 Get Runtime Info
 Subscription Rule :
 Create
 Delete
 Update
 Get
 Namespace:
 Get Runtime Info

19. Azure Service Bus | Message
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 Most messaging systems divide the message data into a header and a body.
The header contains fields that are used by the messaging infrastructure to
manage the flow of messages.
 Body = Payload
 Binary » Serialized Object
 Size = 256KB >> 1MB
 Header
 Built-in Properties : MessageId, Label, CorrelationId
 System Properties : Readonly & Set by service bus
• SequenceNumber
• EnqueuedTimeUtc
• DeliveryCount
• LockToken
 User Properties: custom message metadata
 Header Size = 64 KB

20. SB | Code | Send & Receive Message
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 Options to SEND a message :
 Send One
 Send List
 Schedule » specific datetime
 Cancel scheduled message » Sequence Number
 Register/Unregister Plugins
 Options to RECEIVE a message :
 Receive (One/List) » [PeekLock | ReceiveAndDelete]
 Receive Deferred (One/List)
 Peek (One/List | start from Sequence Number)
 Peek Lock ( Abandon, Complete, Deadletter, Defer, Renew Lock )
 Message Pump :: RegisterMessageHandler
 Register/Unregister Plugins

21. Demo : Queue & Message
• Create Queue
• Create and send Message
• Receive and process message
• Receive Modes
• Receive Batch
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22. SB | Code | SEND Considerations
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 Can’t reach Message Broker! » Communication Issues
 Retry if Exception is Transient >> ServiceBusException.IsTransient
 ServerBusyException
 MessagingCommunicationException
 User local messaging {MSMQ}.
 Cancel Operation.
 Exceptions :
 MessagingEntityNotFoundException
 MessagingEntityDisabledException
 MessageSizeExceededException

23. SB | Code | SEND Considerations
23
 Repeated messages » Duplicate Message Detection
 Entity.RequiresDuplicateDetection
 Entity.DuplicateDetectionHistoryTimeWindow
 Default = 1 min
 From (20 Seconds) To (7 days)
 Keep track of [Message.MessageId] not [Message.Body]
 You can't enable/disable duplicate detection after the queue is created
 Handling Large Messages »
 claim-check pattern

24. 24
• Transaction-based Delivery
• Timeout-based Delivery
• Timeout-based Message Processor
SB | Code | Receive Considerations

25. SB | Code | Receive Considerations
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• Priority Queue pattern
• Message Grouping » Message Session
• Idempotency » https://blog.jonathanoliver.com/idempotency-patterns/
• Handling Failures »
• Poison messages » it is necessary to be able to detect and discard them
• Message expiration » message might have a limited lifetime
• Retry Policy

26. SB | Code | Dead-letter Queue
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 Sub-queue for Queues & Subscriptions holding messages that cannot be delivered to any
receiver, or messages that could not be processed » ##/$DeadLetterQueue
 Created automatically & Cannot be deleted
 No automatic cleanup of the DLQ.
 TTL is not observed
 Can't dead-letter a message from a DLQ
 Moving messages to the DLQ
 By Service Bus (Auto)
 Exceeding MaxDeliveryCount
 Exceeding TimeToLive
 Errors while processing subscription rules
 ForwardTo – destination is disabled or deleted
 Specified by application

27. SB | Topic / Subscription
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 Publish-Subscribe pattern (broadcast)
 provide a one-to-many form of communication, in a
publish/subscribe pattern.
 Each published message is made available to each subscription
registered with the topic.
 Messages are sent to a topic and delivered to one or more
associated subscriptions, depending on filter rules.
 Messages are sent to a topic in the same way they are sent to a
queue, but messages are not received from the topic directly.
Instead, they are received from subscriptions.

28. SB | Topic / Subscription
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 Subscription Rules (Filters & Actions)
 Ex : order organized by region
 Filters
 user-defined properties and system properties
 cannot evaluate the message body
 SQL Filter : SQL-like conditional expression
 NOT - AND - { = | <> | != | > | >= | < | <= }
• IS [NOT] NULL - [NOT] IN () - [NOT] LIKE
• sys.Label LIKE '%bus%'` OR `user.tag IN ('queue', 'topic', 'subscription’)
• sys.Label = 'important'
 Correlation Filter : equal only
 Actions :
 With SQL filter conditions, you can define an action for adding, removing, or replacing
properties and their values.

29. SB | Topic / Subscription
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30. Demo : Topic & Subscription
• Create Topic & Subscription
• Send & Receive Message
• Add Subscription Rule
• Group Chat App
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31. SB | Sessions
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 It’s about grouping message
 Enitity.RequireSession
 Set Message.SessionId property (group-id)
 Receive by MessageSession : When the
MessageSession object is accepted and
while it is held by a client, that client holds
an exclusive lock on all messages with that
session's SessionId that exist in the queue
or subscription, and also on all messages
with that SessionId that still arrive while
the session is held.

32. Demo : Correlation & Session
• Create Topic & Subscription
• Send & Receive Message
• Add Subscription Rule
• Group Chat App
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33. Azure Service Bus | Advanced features
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 Message sessions »
 Auto-forwarding »
 Dead-lettering »
 Scheduled Delivery »
 Message Deferral »
 Batching »
 Transactions »
 Filtering and actions »
 Auto-delete on idle »
 Duplicate detection »
 Handling Large Messages » claim-check pattern
 Message Expiration
 Request-Response Correlation

34. Misc. • Messaging Protocols :
• AMQP
• MQTT
• Messaging vs Events
• SDK for Service Bus (2)
• https://www.nuget.org/profiles/nugetservicebus
• Azure Messaging by the numbers (2017)
• 700B msg ops on ASB / month
• 100K DA SB Namespace
• 5.1T request per week in Event Hub
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35. 35

36. 36
Messaging
Is how different application components in a loosely-coupled
microservice architecture can communicate with each other

37. 37
Questions

38. Thanks 