Dan Rosanova from the Microsoft Product Group talks about why Service Bus is the most sophisticated messaging platform on the cloud. He shares his experiences of how much he has come to know about Service Bus after joining the product team in Microsoft.

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Dan Rosanova
https://twitter.com/DanRosanova
https://www.linkedin.com/in/danrosanova

2. Some history
• Original Service Bus engineering team was (and continues to have
been) from BizTalk in the past – the messaging side of BizTalk in
particular.
• Same team also maintains MSMQ – still

3. I knew messaging
I thought I knew Service Bus

4. Duplicate Detection
• What: Ignore messages that are sent more than once in a specified
time window
• When
• Upstream applications are unpredictable and noisy
• They may send duplicate messages
• Why
• Ever seen a website that says 'don't click buy again to avoid multiple charges'
• How: Use a value as MessageId to control this behavior and set the
window you need on the queue or topic
• Impact: Idempotent processing -> yes you probably need this

5. Scheduled Messages
• What: place a message in a queue or topic that doesn’t “appear” until
a specified future time
• When
• Sender wants to send something now, but doesn't want an action to take
place on it until later
• Take actions to complete or rollback work at a specified point
• Why: Keep your services as simple as possible – we already have it
• How: Set the ScheduledEnqueueTimeUtc on BrokeredMessage
• Impact: Rich temporal control of long running processes

6. Defer
• What: Mark a message to be skipped so it doesn’t keep getting read
off a queue or topic
• When: Whenever you can’t process something immediately, but must
process it later
• Why: Not everything will arrive in the order in which you expect it – if
you need a resequencing aggregator this is a good option
• How: Call BrokeredMessage.Defer BUT SAVE the SequenceNumber
• Impact: Provide logical ordered processing even if your senders are
chaotic

7. If you lose the sequence number of a
message there is no way to read it
WARNING

8. Auto Forward
• What: Forward all messages to another entity
• When: If current senders have an address you don’t want to use
anymore – or if you want more fine grained security
• Why: Change is hard – getting others to change can be impossible!
• How: Set the ForwardTo property on the Queue or the Subscription
(for a topic)
• Impact: Free yourself from decisions you or someone else made last
year

9. Actions on Subscriptions
• What: Change message properties when a subscription receives a
message
• When: You want to create rich topologies
• Why:
• Actions allow you to set user properties that can change routing
• This allows expression of any sort of decision tree – almost like BRE
• How: Use the Action property of the RuleDescription
• Impact: Chaining rules with actions allows for creating very rich
topologies that can express almost any logic But maybe shouldn’t

10. Dead lettering with Auto forward
• What: Send dead letter messages to another entity (queue / topic)
• When: you want more control over where non-deliverable messages
go
• Why: Not all messages fail for the same reason – forwarding to
another entity enables rich failure routing
• How: Use the ForwardDeadLetteredMessagesTo property on Queue
or Subscription

11. Auto-delete on idle
• What: Delete entities that do not have a Send operation called for a
certain amount of time
• When: You need to create entities for specific flows or scenarios that
are transient in nature and don’t want to clean them up
• Why: No one ever wants to clean up their room – we’ll do it for you
• How: Specify a timespan for AutoDeleteOnIdle on the queue or topic
• Impact: A clean namespace is a happy namespace

12. OnMessage (.NET Client Only)
• What: A messaging pump that makes dispatching and processing
messages far easier.
• When: Any time you’re reading Service Bus in .NET
• Why: This is our modern approach – we’re making our client easier to
use - think of EventProcessorHost
• How: Set a lambda or function on OnMessage of the QueueClient or
SubscriptionClient
• Impact: Do more with less.