The combination of cloud, serverless and microservices has taken the service implementation to a different level. Though this has accelerated the monolith to microservices transformation, it has also introduced new complexities around service-to-service communication. With every new service added to the system, the order of communications complexity also increases. Though AWS services such as SNS, SQS and others helped to some extend, they however failed to offer a flexible way to enable filtered routing of messages between microservices. This is where Amazon’s EventBridge makes its mark in alleviating many of these concerns. AWS EventBridge promotes a hub-and-spoke communication model between microservices. With its flexible and powerful message filtering capability, services can have a renewed way of performing event-driven communication between them. This talk will start by explaining EventBridge and then, with the help of real use-case scenarios, explain how to enable message routing and filtering while working with the event bus.

1. Art of Microservices Communication
with
Amazon EventBridge
Sheen Brisals
The LEGO Group
sheenbrisals

3. July 10, 2019
LEGO.com
was switched to
serverless
on AWS

4. AWS services in use
Amazon S3
Amazon SNS
AWS Fargate
AWS Lambda
Amazon Kinesis Data Firehose
Amazon DynamoDB
Amazon API Gateway
AWS Step Functions
Amazon SQS
Amazon EC2
Amazon ECS
Amazon ECR
Amazon VPC
AWS WAF
AWS KMS
AWS Identity and Access
Management (IAM)
AWS X-Ray
Amazon Route 53
AWS CloudTrail
Amazon ElastiCache
Amazon CloudWatch
Amazon EventBridge
AWS CloudFormation
Parameter Store

5. Growing usage stats from production
200+ Lambda functions
40+ microservices
40+ API Gateway endpoints
25+ DynamoDB tables
30+ S3 buckets
20+ SNS topics
60+ SQS queues + DLQs
200+ Systems Manager params

6. Agenda

7. Ø What is EventBridge?
Ø Patterns & Use cases
Ø Schema registry
Ø Cost
Ø Best practices
Ø Takeaways
Amazon EventBridge
Custom event bus
Default event bus
Partner event bus
Event producers
(sources)
Event consumers
(targets)
Partner apps
Custom apps
AWS services
Event bus Filtering &
routing rules

8. What is EventBridge?

12. SNS Limitations
Event filtering nightmare
Filtering requires custom attributes
Can’t control event visibility
Leads to creating topic per event type

13. Amazon
EventBridge

14. Amazon EventBridge is a serverless event bus service
that makes it easy to connect your applications with
data from a variety of sources

15. EventBridge was previously known as
Amazon CloudWatch Events

16. Amazon EventBridge
Custom event bus
Default event bus
Partner event bus
Event producers
(sources)
Event consumers
(targets)
Partner apps
Custom apps
AWS services
Event bus Filtering &
routing rules

17. Why EventBridge?

18. Enables event-driven architecture
Promotes functionless integrationAids just-the-required event routing
Assists trusted partner event ingestion
• Decouples source from target
• Built-in failure retry
• Fully managed & highly scalable
• Flexible event filtering
• Finer control on event flow
• Parallel event routing to targets
• Event ingestion from SaaS platforms
• Cross account event handling
• Helps to act on issues & remediation
• Native integration with API Gateway
• Codeless event filtering
• Codeless event routing

19. Anatomy of an Event
{
}
AWS Section
User Section
JSON document
{
"version": "0",
"id": "6a7e8feb-b491-4cf7",
"detail-type": "order-submit",
"source": “service-checkout",
"account": "123456789012",
"time": "2019-08-29T12:10:21Z",
"region": "eu-central-1",
"resources": ["arn:…checkout-bus"],
"detail": {
}
}

20. Anatomy of an Event
{
}
AWS Section
User Section
JSON document
{
"version": "0",
"id": "6a7e8feb-b491-4cf7",
"detail-type": “order-submit",
"source": “service-checkout",
"account": "123456789012",
"time": "2019-08-29T12:10:21Z",
"region": "eu-central-1",
"resources": ["arn:…checkout-bus"],
"detail": {
}
}
“any valid JSON goes here… but,
a structure is recommended”

21. Anatomy of an Event
{
}
AWS Section
User Section
JSON document
{
"version": "0",
"id": "6a7e8feb-b491-4cf7",
"detail-type": “order-submit",
"source": “service-checkout",
"account": "123456789012",
"time": "2019-08-29T12:10:21Z",
"region": "eu-central-1",
"resources": ["arn:…checkout-bus"],
"detail": {
"metadata": {
“domain": “LEGO-SHOP",
“service": “service_checkout",
"type": "ORDER",
"status": “SUBMITTED"
},
"data": {
"orderNumber": "T123456789",
"customerId": "bf3703467718“,
“locale”: “en-GB”,
“value”: 59.99
}
}
}

22. Anatomy of an Event
{
}
AWS Section
User Section
JSON document
{
"version": "0",
"id": "6a7e8feb-b491-4cf7",
"detail-type": “order-submit",
"source": “service-checkout",
"account": "123456789012",
"time": "2019-08-29T12:10:21Z",
"region": "eu-central-1",
"resources": ["arn:…checkout-bus"],
"detail": {
"metadata": {
“domain": “LEGO-SHOP",
“service": “service_checkout",
"type": "ORDER",
"status": “SUBMITTED"
},
"data": {
"orderNumber": "T123456789",
"customerId": "bf3703467718“,
“locale”: “en-GB”,
“value”: 59.99
}
}
}

23. Event Filtering
Event Routing Rules
Filtering is like trapping the events of interest for
processing needs or requirements
Routing rules are for shaping the (trapped) events
and sending them to consuming targets

24. Event Filtering
{
"detail": {
"metadata": {
“domain”: “LEGO-SHOP”,
“service": “service_checkout”,
"type": “ORDER”,
"status": “SUBMITTED”
},
"data": {
“orderNumber": “T12346789”,
“customerId": “bf3703467718”,
“locale”: “en-GB”,
“value”: 59.99,
“isVIPOrder": “true”
}
}
}
Submitted order event
{
"detail": {
"metadata": {
“service": [“service_checkout“],
"type": [“ORDER“],
"status": [“SUBMITTED“]
}
}
}
All submitted orders
{
"detail": {
"metadata": {
“service": [“service_checkout“],
"type": [“ORDER“],
"status": [“SUBMITTED“]
},
"data": {
“isVIPOrder": [“true“],
}
}
}
Only VIP customer orders
Filter 1
Filter 2

25. Event Filtering
{
"detail-type": [
"AUTHORISATION"
],
"source": [
"payment-service-notifications"
],
"detail": {
"metadata": {
"status": [
"true"
]
},
"data": {
"amount": [
{
"anything-but": "0"
}
],
"validHmac": [
"true"
]
}
}
}
https://amzn.to/3cBBazO

26. https://bit.ly/2MxHbTE

27. Event Routing
• Pass-through event routing
• Entire event data is passed
• Part of the event data routed
• Expose just the required data
• Static data is routed
• Original event not exposed
• Transform to a new event
• Extract the needed data

28. https://bit.ly/2MYjjcx

29. Patterns

30. Ø High level pattern
Ø Event routing patterns
Ø Integration patterns

31. High level pattern
Hub-and-spoke event bus

32. Use case – Checkout event processing
Login
CheckoutPayment
Order
Data
sync
Shipping

33. Use case – Checkout event processing
Login
Checkout
Payment
Order
Data
sync
Shipping

34. Login
Checkout
Payment
Order
Data
sync
Shipping

35. Pattern – Hub-and-spoke event bus
Customer
login
Login Shipping
Send order
to SAP
Data sync
Customer, VIP,
wishlist sync
Checkout
Submit
order
Payment
Authorize
payment
Commerce
platform
Order
Process
order
Order and
customer
updates
Event
relay
Customer
login
Invoke
every
minute
Events Order
complete
Customer
login
Payment
authorized
Order
submit
Order
complete
EventBridge
FIFO
queue

36. Event routing patterns
Static event flow

37. Use case – Order count monitoring
Checkout Monitor
Order countsOrder placed

38. Pattern – Static event flow
Checkout Monitor
Order placed Order prompt

39. {
"detail": {
"metadata": {
“domain": “LEGO-SHOP",
“service": “service_checkout",
"type": "ORDER",
"status": “SUBMITTED"
},
"data": {
"orderNumber": "T123456789",
"customerId": "bf3703467718“,
“locale”: “en-GB”,
“value”: 59.99
}
}
}
}
Pattern – Static event flow
Checkout Monitor
Order placed Order prompt
Extensive
order
data
{
“prompt": “order"
}
Static
constant
data
• Original event is not exposed
• Ideal for hiding sensitive data
• Controls data flow to 3rd parties

40. Filtered event flow
Event routing patterns

41. Use case – Payments notification
Payment specific details
Operations specific data

42. Pattern – Filtered event flow
Payment
service
Accounts
systemNew payment Payment data

43. {
"detail": {
"metadata": {
“domain": “LEGO-PAYMENTS",
“service": “payment-authoriser",
"type": “CREDITCARD",
"status": “AUTHORISED"
},
"data": {
“paymentId": “XY12ABC",
“clientId": “bf3703467718“,
“orderNumber”: ”T123456789”,
“amount”: 29.99,
“currency”: ”GBP”,
“cardType”: ”VISA”
}
}
}
}
Pattern – Filtered event flow
Payment event
$.detail.data
Data path
• Send only the required data
• Tailor the input as per target
{
“paymentId": “XY12ABC",
“clientId": “bf3703467718“,
“orderNumber”: ”T123456789”,
“amount”: 29.99,
“currency”: ”GBP”,
“cardType”: ”VISA”
}
Part of the event data

44. Transformed event flow
Event routing patterns

45. Use case – Carpark status noticeboard

46. Pattern – Transformed event flow
Vehicle
entry
Billboard
feeder
Vehicle enter
Car park status
Vehicle
exit
Vehicle exit

47. {
"detail": {
"metadata": {
“domain": “LEGOLAND-CARPARK",
“service": “vehicle-entry",
“carpark": “Upper Level",
"type": “CAR",
"status": “ENTERED"
},
"data": {
“registration": “XY12ABC",
“entryTime": “1576826331“,
“spaces”: 125
}
}
}
}
Pattern – Transformed event flow
Vehicle entry event
{
“location": “$.detail.metadata.carpark“,
“available": “$.detail.data.spaces“,
}
Data paths
• Limits event data exposure
• Customize target delivery data
“<location> has <available> spaces!!"
Data template
Upper Level has 125 spaces!!

48. Passthrough event flow
Event routing patterns

49. AnalyticsData storeEvent pipelineEvent producers
Use case – Event persistence for analysis

50. Pattern – Passthrough event flow
Service 1
Analytics
Service 2
Event storeEvent stream

51. Integration patterns
Functionless EventBridge integration

52. Events
processing
Notification
events
Async
notifications
3rd party
application
Use case – 3rd party notification webhooks
Notification
receiver

53. Pattern – Functionless EventBridge integration
Target 1
Event targets
3rd party
application
Target 2
Target n
Webhook API
• Use native integration
• Avoid unnecessary functions

54. Pattern – Functionless EventBridge integration
Target 1
Event targets
3rd party
application
Target 2
Target n
Webhook API

57. {
“Entries": [
{
“DetailType": “payment-notification",
“Source": “aPP",
“EventBusName": “gbshebri-event-bridge",
“Detail": “$util.escapeJavaScript($input.json(‘$’))"
}
]
}

58. Usecases

59. Use case: Submit order notification

60. Rewards
platform
Customer
Shipment
Order
All orders
Only VIP customer orders
Ecommerce order completion flow

61. Shipping
Checkout Rewards
Payments
Inventory
Analytics
Disorderly service interactions

62. Shipping
Checkout Rewards
Payments
Orderly service interactions with EventBridge

63. Shipping
Send order
to SAP
Checkout
Submit
order
Rewards
Process
rewards
New order
All orders
VIP
customer
orders
Service event flow

64. Shipping
Send order
to SAP
Checkout
Submit
order
Rewards
Process
rewards
{
"detail": {
"metadata": {
“domain”: “LEGO-SHOP”,
“service": “service_checkout”,
"type": “ORDER”,
"status": “SUBMITTED”
},
"data": {
“orderNumber": “T12346789”,
“customerId": “bf3703467718”,
“locale”: “en-GB”,
“value”: 59.99,
“isVIPOrder": “true”
}
}
}
Submitted order event

65. Shipping
Send order
to SAP
Checkout
Submit
order
Rewards
Process
rewards
{
"detail": {
"metadata": {
“service": [“service_checkout“],
"type": [“ORDER“],
"status": [“SUBMITTED“]
}
}
}
{
"detail": {
"metadata": {
“domain”: “LEGO-SHOP”,
“service": “service_checkout”,
"type": “ORDER”,
"status": “SUBMITTED”
},
"data": {
“orderNumber": “T12346789”,
“customerId": “bf3703467718”,
“locale”: “en-GB”,
“value”: 59.99,
“isVIPOrder": “true”
}
}
}
All submitted orders
Submitted order event

66. Shipping
Send order
to SAP
Checkout
Submit
order
Rewards
Process
rewards
{
"detail": {
"metadata": {
“service": [“service_checkout“],
"type": [“ORDER“],
"status": [“SUBMITTED“]
},
"data": {
“isVIPOrder": [“true“],
}
}
}
{
"detail": {
"metadata": {
“service": [“service_checkout“],
"type": [“ORDER“],
"status": [“SUBMITTED“]
}
}
}
{
"detail": {
"metadata": {
“domain”: “LEGO-SHOP”,
“service": “service_checkout”,
"type": “ORDER”,
"status": “SUBMITTED”
},
"data": {
“orderNumber": “T12346789”,
“customerId": “bf3703467718”,
“locale”: “en-GB”,
“value”: 59.99,
“isVIPOrder": “true”
}
}
}
Only VIP customer orders
All submitted orders
Submitted order event

67. Use case: Payment device status monitor

68. LEGO store
employee
Order
Get available
devices
Instore
order App
Payment
devices

69. Payment
provider
Notifications
receiver
(web hook)
Payment
devices
Device status
notifications
Stores the
status
Updates
monitoring
Status
API
Status
store
Status
dashboard

70. {
"SaleToPOIRequest": {
"EventNotification": {
"EventDetails": "newstate",
"EventToNotify": "Shutdown",
"TimeStamp": "2019-08-07…"
},
"MessageHeader": {
"SaleID": "POSSystemID12345",
"ProtocolVersion": "3.0",
"MessageType": "Notification",
"POIID": "V400m-324688179",
"MessageClass": "Event",
"MessageCategory": "Event",
"DeviceID": "1517998561"
}
}
}
{
“Entries": [
{
“DetailType": “device-status",
“Source": “Adyen",
“EventBusName": “payments-bus",
“Detail": “$util………."
}
]
}
{
"version": "0",
"id": "73bb6b40",
"detail-type": "device-status",
"source": "Adyen",
"account": "12345",
"time": "2020-01-19T14:44:24Z",
"region": "eu-central-1",
"resources": [],
"detail": {
"SaleToPOIRequest": {
"EventNotification": {
"EventDetails": "newstate",
"EventToNotify": "Shutdown",
"TimeStamp": "2019-08-07..."
},
"MessageHeader": {
"SaleID": "POSSystemID12345",
"ProtocolVersion": "3.0",
"MessageType": "Notification",
"POIID": "V400m-324688179",
"MessageClass": "Event",
"MessageCategory": "Event",
"DeviceID": "1517998561"
}
}
}
}
Raw event from the payment provider
API Gateway template
EventBridge event

71. Payment
provider
Notifications
receiver
(web hook)
Payment
devices
Device status
notifications
Stores the
status
Updates
monitoring
Status
API
Status
store
Status
dashboard

72. {
"version": "0",
"id": "73bb6b40",
"detail-type": "device-status",
"source": "Adyen",
"account": "12345",
"time": "2020-01-19T14:44:24Z",
"region": "eu-central-1",
"resources": [],
"detail": {
"SaleToPOIRequest": {
"EventNotification": {
"EventDetails": "newstate",
"EventToNotify": "Shutdown",
"TimeStamp": "2019-08-07..."
},
"MessageHeader": {
"SaleID": "POSSystemID12345",
"ProtocolVersion": "3.0",
"MessageType": "Notification",
"POIID": "V400m-324688179",
"MessageClass": "Event",
"MessageCategory": "Event",
"DeviceID": "1517998561"
}
}
}
} EventBridge event
{
"detail-type": ["device-status“],
"source": ["Adyen“],
}
Event filter pattern
For monitoring target – Transformed event flow
{
“event": “$.detail.SaleToPOIRequest.EventToNotify“,
“device": “$.detail.MessageHeader.DeviceID“
}
{
“eventName": <event>,
“deviceId": <device>
}
Monitoring event

73. Payment
provider
Notifications
receiver
(web hook)
Payment
devices
Device status
notifications
Stores the
status
Updates
monitoring
Status
API
Status
store
Status
dashboard

74. Payment
provider
Notifications
receiver
(web hook)
Payment
devices
Device status
notifications
Stores the
status
Updates
monitoring
Status
API
Status
store
Status
dashboard

75. Use case: Async webhook notifications

77. Payment
provider
Notifications
receiver
(web hook)
Async payment
notifications
Update
payments
Failures
topic
Payments
store
Teams
channel
Status
dashboard
Dispatch
status

78. Payment
provider
Notifications
receiver
(web hook)
Async payment
notifications
Update
payments
Failures
topic
Payments
store
Teams
channel
Status
dashboard
Dispatch
status
Passthrough event flow
Transformed event flow

79. Schema Registry

80. Amazon EventBridge Schema Registry is a repository
that allows to discover, create and manage OpenAPI
schemas for events on EventBridge

81. Amazon
EventBridge

82. AWSServiceEvents
Schema of all
services on
EventBridge
Preloaded and
ready for use
CustomCreatedEvents
Create schema
Upload schemas
Generate schema
from JSON data
AutoGeneratedEvents
Auto generated
Captured from the
actual event
Enable at the
event bus level

83. AWS Schema Registry

84. AWSServiceEvents
Schema of all
services on
EventBridge
Preloaded and
ready for use
CustomCreatedEvents
Create schema
Upload schemas
Generate schema
from JSON data
AutoGeneratedEvents
Auto generated
Captured from the
actual event
Enable at the
event bus level

85. Custom Schema Registry

86. AWSServiceEvents
Schema of all
services on
EventBridge
Preloaded and
ready for use
CustomCreatedEvents
Create schema
Upload schemas
Generate schema
from JSON data
AutoGeneratedEvents
Auto generated
Captured from the
actual event
Enable at the
event bus level

87. Schema Discovery

88. • Use one custom schema registry per event bus
• com.LEGO.ecom.schema.registry
• Payment Service Schema Registry
• Follow a naming convention for schema
• com.LEGO.ecom.checkout.OrderComplete
• com.LEGO.ecom.email.RegistrationRequest
• [org].[domain].[microservice].[EventName]

89. EventBridge Costs?

90. Free
Pay
• Filtering rules – FREE
• Routing rules - FREE
• Events delivery – FREE
• Schema registry - FREE
• Event ingestion - $1 per million events
• Schema discovery - $0.10 per million events ingested for discovery
Know this
• 1 event measure = 64 KB data
• 100 KB event data = 2 events

91. Best Practices

92. • Use EventBridge for microservices communications
• Use SNS for internal service communications
• Try and follow a defined structure for custom events
• Implement finer controlled event flow
• Limit event data exposure beyond the service bus
• Events are state changes and action notifiers; not log statements
• Implement the targets as idempotent where applicable

93. Beware of…

94. • At least once event delivery with 24 hour retry
• Events with no subscriber are dropped / lost
• No support for DLQ setup at event subscription
• Cannot route events to an event bus in the same account
• Events should be of defined JSON structure format
• Latency is roughly around 0.5 seconds
• Throughput is lower than SNS
• SaaS partners can be of event source; not targets

95. Takeaways

96. • Use EventBridge for microservices communication
• Have a defined custom event structure
• Control the event exposure to downstream targets
• Incrementally migrate to use EventBridge
• Explore the partner SaaS event sharing option
• Event bus is for events and not for logs!

97. go
build
serverless
thank
you!@sheenbrisals