Reliable integrationswith NServiceBus

Andreas ÖhlundEnterprise Development Expert

Agenda

• War story

• Dragons and how to manage them

• A “saga” with a happy ending

• Q & A

Fact:A trip to dragon territory cantake a while...

The usual waypublic void Handle(OrderPlaced message){

var order = new Order{ Id = message.OrderID };

order.TrackingCode = fedex.BookPickup(order); order.Status = ShippingStatus.PickupBooked;

repository.Save(order);}

The usual waypublic void Handle(OrderPlaced message){

var order = new Order{ Id = message.OrderID };

order.TrackingCode = fedex.BookPickup(order); order.Status = ShippingStatus.PickupBooked;

repository.Save(order);}

2:

3:

The usual waypublic void Handle(OrderPlaced message){

var order = new Order{ Id = message.OrderID };

order.TrackingCode = fedex.BookPickup(order); order.Status = ShippingStatus.PickupBooked;

repository.Save(order);}

This might take a while!2:

3:

Fact:Dragons doesn’t support transactions.

TX

Database rollback

DB

Order

Store

Ship

TX

Database rollback

DB

Order

Store

Ship

TX

Database rollback

DB

Order

Store

Ship

No TXSupport

TX

Database rollback

DB

Order

Store

Ship

No TXSupport

TX

Database rollback

DB

Order

Store

Ship

Did we just loose an order?

No TXSupport

TX

Database rollback

DB

Order

Store

Ship

No TXSupport

TX

Database rollback

DB

Order

Store

Ship

Order Http

Design guideline

“Interact with non transactional resources using separate endpoints”

R# Extract endpoint public void Handle(OrderPlaced message){ repository.Save(new Order { Id = message.OrderID, Status = ShippingStatus.AwaitingShipment });

bus.Send<BookShipment>(m => { m.OrderID = message.OrderID; });}

R# Extract endpoint public void Handle(OrderPlaced message){ repository.Save(new Order { Id = message.OrderID, Status = ShippingStatus.AwaitingShipment });

bus.Send<BookShipment>(m => { m.OrderID = message.OrderID; });}

R# Extract endpoint public void Handle(OrderPlaced message){ repository.Save(new Order { Id = message.OrderID, Status = ShippingStatus.AwaitingShipment });

bus.Send<BookShipment>(m => { m.OrderID = message.OrderID; });}

R# Extract endpoint

public void Handle(ShipmentBooked message){

var order = repository.Get<Order>(message.OrderID);

order.TrackingCode = message.TrackingCode;

repository.Save(order);}

TX

Consistency across rollbacks

Order

TX

Consistency across rollbacks

Order

DBStore

TX

Consistency across rollbacks

Order

DBStore

Book shipment MQ

TX

Consistency across rollbacks

Order

DBStore

Book shipment MQ

TX

Consistency across rollbacks

Order

DBStore

Book shipment MQ

TX

Consistency across rollbacks

Order

DBStore

Book shipment MQ

Not all return from a trip to the dragons

Fact:Not everyone will make it back.

TX

What happens if the response is lost?

BookShipment

Fedex.Ship

TX

What happens if the response is lost?

BookShipment

Fedex.Ship

TimeoutException

TX

What happens if the response is lost?

BookShipment

Fedex.Ship

TimeoutException

Commit

TX

What happens if the response is lost?

BookShipment

Fedex.Ship

TimeoutException

IntegrationEndpoint

IdempotencyBookShipment

IntegrationEndpoint

IdempotencyBookShipment

http://fedex.com/ship ?id=xyz123

Commit

IntegrationEndpoint

IdempotencyBookShipment

http://fedex.com/ship ?id=xyz123

Commit

IntegrationEndpoint

IdempotencyBookShipment

http://fedex.com/ship ?id=xyz123

TimeoutExceptionX

Commit

IntegrationEndpoint

IdempotencyBookShipment

http://fedex.com/ship ?id=xyz123

http://fedex.com/ship?id=xyz123

TimeoutExceptionX

Commit

IntegrationEndpoint

IdempotencyBookShipment

http://fedex.com/ship ?id=xyz123

Discard

http://fedex.com/ship?id=xyz123

TimeoutExceptionX

Commit

IntegrationEndpoint

IdempotencyBookShipment

http://fedex.com/ship ?id=xyz123

Discard

http://fedex.com/ship?id=xyz123

TimeoutExceptionX

Commit

IntegrationEndpoint

IdempotencyBookShipment

http://fedex.com/ship ?id=xyz123

Discard

http://fedex.com/ship?id=xyz123

TimeoutExceptionX

ShipmentBooked

Fact:A trip to the dragons may be costly.

Timeouts vNext

• Thread.Sleep is not a good solution

• Need a way to have durable timeouts

• The NServiceBus timeout manager solves this for us

Fact:Dragons have home turf advantage.

Scalable integrations

• Manage traffic peaks

• Allow you to control the pace

Use throttling to:

A more scalable design

Client Server

A more scalable design

Client Server

Request

A more scalable design

Client Server

Request Send

A more scalable design

Client Server

Request

Ticket - come back in Thttp://fedex.com/responses/xyz123

Send

A more scalable design

Client Server

Request

Ticket - come back in Thttp://fedex.com/responses/xyz123

Send

CacheRecv

A more scalable design

Client Server

Request

Ticket - come back in Thttp://fedex.com/responses/xyz123

} T

http://fedex.com/responses/xyz123

Send

CacheRecv

A more scalable design

Client Server

Request

Ticket - come back in Thttp://fedex.com/responses/xyz123

} T

http://fedex.com/responses/xyz123

Response / come back in T2

Send

CacheRecv

A more scalable design

Client Server

Request

Ticket - come back in Thttp://fedex.com/responses/xyz123

} T

http://fedex.com/responses/xyz123

Response / come back in T2

Send

CacheRecv

A more scalable design

Client Server

Request

Ticket - come back in Thttp://fedex.com/responses/xyz123

} T

http://fedex.com/responses/xyz123

Response / come back in T2

Send

CacheRecv

Using sagas to control message flow

BookShipment

IntegrationSaga

FedexEndpointTimeout

ManagerFedex

Using sagas to control message flow

BookShipment

IntegrationSaga

FedexEndpointTimeout

Manager

Get ticket

Fedex

Using sagas to control message flow

BookShipment

IntegrationSaga

FedexEndpointTimeout

Manager

Get ticket

Fedex

Using sagas to control message flow

BookShipment

IntegrationSaga

FedexEndpointTimeout

Manager

Get ticket

Fedex

Using sagas to control message flow

BookShipment

IntegrationSaga

FedexEndpointTimeout

Manager

Wake me up in T

Get ticket

Fedex

Using sagas to control message flow

BookShipment

IntegrationSaga

FedexEndpointTimeout

Manager

Wake me up in T

Get ticket

Fedex

Using sagas to control message flow

BookShipment

IntegrationSaga

FedexEndpointTimeout

Manager

Wake me up in T

Get ticket

Get Data

Fedex

Using sagas to control message flow

BookShipment

IntegrationSaga

FedexEndpointTimeout

Manager

Wake me up in T

Get ticket

Get Data

Fedex

Using sagas to control message flow

BookShipment

IntegrationSaga

FedexEndpointTimeout

Manager

Wake me up in T

Get ticket

Get Data

Fedex

Code...

Thanks for listening!

Thanks for listening!

Andreas ÖhlundEnterprise Development Expert