We built event-driven user interfaces for decades. What about bringing the same approach to mobile, web, and IoT backend applications? You have to understand how data flows and what is the propagation of changes, using reactive programming techniques. You can focus on the core functionalities to build and the relationships among the resources you use. Your application behaves similarly to a “spreadsheet”, where depending resources are updated automatically when something “happens”, and is decomposed into scalable microservices without having to manage the infrastructure. The resulting architecture is efficient and cost effective to run on AWS and managing availability, scalability and security becomes part of the implementation itself.

1. Event-­‐Driven
Serverless
Apps
Danilo Poccia, Technical Evangelist
@danilop

2. Event-Driven in the Front End

3. Name
Email
Create New User
Submit
Check the “Name” syntax is right
(only letters and spaces)
Check the “Email” syntax is right
(something@some.domain)
Create the new user using
provided Name and Email
User Interface Actions

4. Name
Email
Create New User
Submit
Check the “Name” syntax is right
(only letters and spaces)
Check the “Email” syntax is right
(something@some.domain)
Create the new user using
provided Name and Email
User Interface ActionsObservers
Target Action

5. What about the Back End ?

6. Users

7. Internet
Users

8. Back End
Logic
Internet
Users

9. Back End
Data
Back End
Logic
Internet
Users

10. Back End
Data
Application Back End
Back End
Logic
Internet
Users

11. Application Back End
Web Browsers
Back End
Data
Back End
Logic

12. Application Back End
Web Browsers
Mobile Apps Back End
Data
Back End
Logic

13. Application Back End
Web Browsers
Mobile Apps
IoT Devices
Back End
Data
Back End
Logic

14. Application Back End
Web Browsers
Mobile Apps
IoT Devices
Other Services
Back End
Data
Back End
Logic

15. Application Back End
Files
Databases
Web Browsers
Mobile Apps
IoT Devices
Other Services
Back End
Logic

16. HTML, CSS, JavaScript
& Multimedia Content
API Calls
Application Back End
Web Browsers
Mobile Apps
IoT Devices
Other Services
Files
Databases
Back End
Logic

17. API Calls
Application Back End
HTML, CSS, JavaScript
& Multimedia Content
Web Browsers
(JavaScript)
Mobile Apps
IoT Devices
Other Services
By using JavaScript,
Web Browsers can behave
like the other clients,
such as Mobile Apps
or IoT Devices
Files
Databases
Back End
Logic

18. API Calls
Application Back End
HTML, CSS, JavaScript
& Multimedia Content
Web Browsers
(JavaScript)
Mobile Apps
IoT Devices
Other Services
Files
Databases
Back End
Logic

19. Client
Application
API Calls
Application Back End
HTML, CSS, JavaScript
& Multimedia Content
The Client Application
can be a Web Browser,
a Mobile App,
an IoT Device,
or another Service
We can now decouple the
back end implementation
from the device
used by our users
Files
Databases
Back End
Logic

20. Client
Application
API Calls
Application Back End
HTML, CSS, JavaScript
& Multimedia Content
The Client Application
can be a Web Browser,
a Mobile App,
an IoT Device,
or another Service
Files
Databases
Back End
Logic

21. Introducing AWS Lambda

22. Context
Function
Event
AWS Lambda
Result
RequestResponse
Function
Invocation
Lambda API Call
Synchronous Invocations

23. Context
Function
Event
AWS Lambda
Event
Function
Invocation
Lambda API Call
Asynchronous Invocations

24. ContextContextResource
ContextContextResource
Context
Function
Event
AWS Lambda Managed by AWS
Not managed
by AWS
Result
(Optional)
Function
Invocation
Resources can
be files, records
in a DB, etc.
Lambda API Call
Functions can Modify Resources

25. Events
(Context)
Events
(Context)
Generated
by AWS
Not generated
by AWS
ContextContextResource
ContextContextResource
Context
Function
Event
AWS Lambda Managed by AWS
Not managed
by AWS
Result
(Optional)
Function
Invocation
Lambda API Call
Resources can Generate more Events

26. Events
(Context)
Events
(Context)
Generated
by AWS
Not generated
by AWS
ContextContextResource
ContextContextResource
AWS Lambda Managed by AWS
Not managed
by AWS
Direct Use
of Resource
For example,
a file is uploaded
or something is written
in a database
AWS Lambda
Function 2
Function 3
Function 1
Events can Trigger more Functions

27. Sample Event-Driven Serverless
Media-Sharing Application

28. Client
Application
Event-driven
Backend
User

29. Client
Application
Get Content
Index
Get Content
Upload Content
with Metadata
Update Content
Metadata
Get Content
Metadata
AWS Lambda
User

30. Client
Application
Get Content
Index
Get Content
Upload Content
with Metadata
Update Content
Metadata
Get Content
Metadata
Files
(Multimedia)
Database
AWS Lambda
User
Resources

31. Client
Application
Get Content
Index
Get Content
and Thumbnails
Upload Content
with Metadata
Update Content
Metadata
Get Content
Metadata
Files
(Multimedia)
Database
Build
Thumbnails
Update
Content Index
Extract
and Update
Metadata
Event:
new or
updated
file
Event:
new or updated
content metadata
AWS Lambda
User
Resources

32. Client
Application
Get Content
Index
Get Content
and Thumbnails
Upload Content
with Metadata
Update Content
Metadata
Get Content
Metadata
Files
(Multimedia)
Database
Build
Thumbnails
Update
Content Index
Extract
and Update
Metadata
Event:
new or
updated
file
Event:
new or updated
content metadata
AWS Lambda
User
Resources
Access to AWS services,
such as AWS Lambda,
and the resources
used by your application,
should be protected

33. Get Content
Index
Get Content
and Thumbnails
Upload Content
with Metadata
Update Content
Metadata
Get Content
Metadata
Files
(Multimedia)
Database
Build
Thumbnails
Update
Content Index
Extract
and Update
Metadata
User Mobile
App

34. Get Content
Index
Get Content
and Thumbnails
Upload Content
with Metadata
Update Content
Metadata
Get Content
Metadata
Files
(Multimedia)
Database
Build
Thumbnails
Update
Content Index
Extract
and Update
Metadata
User
Web Browsers
(JavaScript)

35. Calling Lambda Function from the Client

36. Client
Application
AWS Lambda
Function
AWS Lambda
Invoke API
User
Calling Lambda Functions Directly

37. Client
Application
AWS Lambda
Function
AWS Lambda
Invoke API
Get Temporary
AWS Credentials Amazon
Cognito
User
Getting AWS Credentials from Amazon Cognito

38. Client
Application
AWS Lambda
Function
Amazon
Cognito
Amazon
API Gateway
Get Temporary
AWS Credentials
Web API Modeling,
Caching, Throttling,
Logging, CDN, etc.
User
Exposing Functions as Web API

39. Client
Application
AWS Lambda
Function
Amazon
API Gateway
Web API Modeling,
Caching, Throttling,
Logging, CDN, etc.
User
Exposing Functions as Public Web API

40. https://some.domain/stage/resource1/resource2/…/resourceN
GET
POST
PUT
DELETE
HEAD
PATCH
OPTIONS
Unique domain
that you can
customize
API stage, for example
prod, test, dev, or v0, v1, …
Resources as part of the URL
HTTP verb
used when
accessing the URL
function1
function2
function3
function1
function2
function3
function1
Function
to execute
Web API to Lambda Functions Integration

41. Introducing Amazon Cognito Identity

42. Client
Application
Amazon
Cognito
1. Using the
Application
2. Send
Identity Pool ID
3. Get Identity ID +
AWS Temp Credentials
for the Unauthenticated Role
All AWS Services,
including
APIs managed
by Amazon
API Gateway
AWS
Services
4. Call AWS Services using
AWS Temp Credentials
User
Amazon Cognito for Unauthenticated Identities

43. Client
Application
Amazon
Cognito
1. Using the
Application
2. Send
Identity
Provider
Credentials
3. Get
Authentication
Token
4. Send
Identity Pool ID +
Authentication Token
6. Get Identity ID +
AWS Temp Credentials
for the Authenticated Role
All AWS Services,
including
APIs managed
by Amazon
API Gateway
AWS
Services
7. Call AWS Services using
AWS Temp Credentials
5. Check
Authentication Token
with Identity Provider
Identity
Provider
User
Amazon Cognito for Authenticated Identities

44. Client
Application
Custom
Authentication
Amazon
Cognito
1. Using the
Application
2. Send
Identity
Provider
Credentials
4. Send
Authentication
Token
to Client 5. Send
Identity Pool ID +
Authentication Token
6. Get Identity ID +
AWS Temp Credentials
for the Authenticated Role
All AWS Services,
including
APIs managed
by Amazon
API Gateway
AWS
Services
7. Call AWS Services using
AWS Temp Credentials
3. Get
Authentication
Token from Cognito
User
Amazon Cognito for Developer Authenticated Identities

45. Best Practices

46. !
Reactive Manifesto

47. !
Reactive Manifesto

48. Reactive Manifesto
Distributed
Asynchronous
Eventual Consistency
!

49. <demo>
…
</demo>

50. Danilo Poccia
Technical Evangelist
@danilop