Real-world development Decomposing a serverless skills-based routing application on AWS Presenter: Adam Larter, Principal Solutions Architect, Developer Specialist

1. Adam Larter
Principal Solutions Architect, Developer Specialist
Real-world development
Decomposing a serverless skills-based routing application on AWS

2. CUSTOMER SPECIFICATION
• A system that can direct my customers’ queries to the best-suited team
member with the right skills to help the customer
• A mobile app that my staff use to see tasks assigned to them
• Push notifications to alert team members when there’s work to do
• Staff ‘accept’ and ‘complete’ tasks as they work on them
• Automatic staff registration – no admin intervention
• An admin portal to securely manage
and monitor activity
D E V L O U N G E

3. • The ability to see trends – busy times of the day so I can schedule staff
• The ability to create new departments and specialisations
• The ability to send ad-hoc messages to team members, and re-assign tasks
if need be
• A simple interface for my team members and of course, my customers
• Ability to embrace the API economy and create a SaaS offering that provides
throttling and quota management
CUSTOMER SPECIFICATION
D E V L O U N G E

4. • Use AWS IoT Buttons as the customer interface – simple button press
• Multi-modal use of the buttons – single, long and double press actions
• No relational databases – all NoSQL
• Microservice architecture
• Serverless! And Service-full!
• Low-cost, low-operational maintenance
TECHNICAL SPECIFICATION
D E V L O U N G E

5. • Infrastructure as code – complete DR story for my system
• Integrated security from user app/admin portal to back-end
• Decoupled, asynchronous processing where possible
• Fast development iteration
D E V L O U N G E
TECHNICAL SPECIFICATION

6. D E V L O U N G E
AWS IoT BUTTON

7. DEMONSTRATION

8. Amazon API Gateway AWS Lambda Amazon CognitoAmazon DynamoDB
Host and route our
API calls, manage
quotas, security and
SDK generation
Execute our app’s
business logic without
having to worry about
servers
Integrated
AuthZ and AuthN
Highly durable and
performant data store
D E V L O U N G E
MAIN AWS COMPONENTS

9. ARCHITECTURE
Amazon
CloudFront
Amazon API
Gateway
AWS IoT AWS IoT
rule
AWS Lambda
Function
Amazon
DynamoDB
Amazon
SNS
AWS Lambda
Function
Amazon Elasticsearch
Service
AWS
Lambda
Functions
Decoupled statistics
processing
IoT Ingress processing
Web API handling
Statistics engine
Data ingress & API processing
Amazon
Cognito
Mobile apps
Websites
API
ConsumersAuth

10. DEPLOYMENT
D E V L O U N G E

11. Options for serverless
DevOps deployment on AWS Toolchain
deployment
(CI/CD)
Frameworks
(Claudia.js, Chalice,
Serverless.com
Kappa, etc.)
Manual
deployment
(Console/CLI)
Code in-place
Whole stack update
(SAM / CloudFormation)

12. Serverless Application Model (SAM) / CloudFormation
Declaratively define your serverless environment including API Gateway
endpoints and Lambda functions – Swagger import supported
Manual & CI/CD pipelines
AWS Console
AWS CLI scripting
Serverless frameworks
Claudia.js / Serverless.com (Python & NodeJS),
Chalice, Zappa, Kappa and others
DEPLOYMENT OPTIONS
D E V L O U N G E

13. AWS SAM is a specification that defines serverless applications
Defines simplified CloudFormation syntax for expressing
serverless resources
Covers APIs (API Gateway), Lambda functions, event source
mappings and Amazon DynamoDB tables
Lambda environment variables and event sources
AWS SERVERLESS APPLICATION MODEL (SAM)
D E V L O U N G E

14. AWSTemplateFormatVersion: '2010-09-09'
Transform: 'AWS::Serverless-2016-10-31'
Resources:
MySimpleFunction:
Type: AWS::Serverless::Function
Properties:
Handler: index.handler
Runtime: nodejs4.3
CodeUri: s3://<source-bucket>/MyCode.zip
Policies: AmazonDynamoDBFullAccess
Environment:
Variables:
TABLE_NAME: !Ref Table
Events:
MyUploadEvent:
Type: S3
Properties:
Id: !Ref MyBucket
Events: Create
MyBucket:
Type: AWS::S3::Bucket
Environment variable declarations
Function definition
Event source mapping
Function execution policy / role
AWS SERVERLESS APPLICATION MODEL (SAM)

15. DESIGN TIPS
D E V L O U N G E

16. • Automate the base infrastructure with CloudFormation/SAM
• Use a developer automation tool to do the heavy lifting and support fast,
iterative development – grunt, gulp, npm… your favourite tool du jour
• Layout your project from the start to allow for local runs, local testing and
easy deployment into your AWS Dev environment
• Every developer in your team has their own full-stack environment and can
deploy to it and test prior to checking in code – fast, contention-free
iteration when writing and debugging features
DESIGN TIPS
D E V L O U N G E

17. AN ENVIRONMENT FOR EACH DEV + SHARED TEST
API
Gateway
Amazon
Cognito
AWS
Lambda
functions
Amazon
DynamoDB
Developer1
API
Gateway
Amazon
Cognito
AWS
Lambda
functions
Amazon
DynamoDB
Developer2
API
Gateway
Amazon
Cognito
AWS
Lambda
functions
Amazon
DynamoDB
SharedTest/UAT
CI/CD Source Control
Developer deploys fast
iterations to dedicated
environment
CI/CD toolchain deploys
committed code to shared
test/staging environment using
SAM/CloudFormation
toProduction

18. • Use CloudFormation/SAM to build your dev environment – From. The. Start!
Repeatable… Reliable... Reusable... Easily stamp out multiple dev
environments
• Plan to break your application functionality into decoupled modules and
embrace asynchronicity and background processes with CW Events
• Never keep application state in your Lambda function code – keep state in
a shared cache and cache everything all the time – design for multi-tenancy
• Use the right data store – do you REALLY need an RDBMS?
D E V L O U N G E
DESIGN TIPS

19. Agents
Capabilities Categories
TasksButtons
0..*
1..*
*..*
1..*
DATA ENTITY RELATIONSHIPS
D E V L O U N G E
SELECT * FROM TASKS
INNER JOIN AGENTS
INNER JOIN BUTTONS
INNER JOIN CAPABILITIES…
Capabilities
1..*

20. Agents
Categories
Tasks
Buttons
DATA ENTITY RELATIONSHIPS
D E V L O U N G E
Capabilities Amazon Elasticache
memcached
or Redis
AWS Lambda
manages ‘joins’ in the middle-tier
and refreshes cache as needed
Tasks pulled from DynamoDB
SSoT for ancillary
data held in DynamoDB

21. • Use DynamoDB Local and memcached for testing your data model
http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/DynamoDBLocal.html
DESIGN TIPS
D E V L O U N G E

22. • Local config.json for fast, iterative development
and environment variables to override config settings at runtime
DESIGN TIPS
D E V L O U N G E

23. Let’s look at some code
D E V L O U N G E

24. • Local config.json for fast, iterative development
and environment variables to override config settings at runtime
• Switch behaviour based on the LAMBDA_TASK_ROOT variable
to facilitate fast, local testing and iteration
• “Finaliser” to give back resources – and design tests to confirm you are
calling the finaliser before calling Lambda
(language dependent)
• Use locks, not just moats when it comes to security
DESIGN TIPS
D E V L O U N G E

25. AWS COGNITO
User Pools & Identity Federation
D E V L O U N G E

26. ADMIN AUTH: COGNITO USER POOLS
Mobile
apps
Admin Portal
Partner
Services
AWS Lambda
functions
API
Gateway
Amazon
Cognito

27. ADMIN AUTH: COGNITO USER POOLS
Mobile
apps
Admin Portal
Partner
Services
AWS Lambda
functions
API
Gateway
Amazon
Cognito

28. ADMIN AUTH: COGNITO USER POOLS
Mobile
apps
Admin Portal
Partner
Services
AWS Lambda
functions
API
Gateway
Amazon
Cognito
403 – Unauthorised from API GW
403 – Unauthorised from app
Cognito Identity
Token

29. Mobile
apps
Admin Portal
Partner
Services
AWS Lambda
functions
API
Gateway
Amazon
Cognito
3rd Party Identity
Facebook, Google,
Twitter, OpenID etc
Public Identity
Provider
USER AUTH: SIGV4 / IAM

30. Mobile
apps
Admin Portal
Partner
Services
AWS Lambda
functions
API
Gateway
Amazon
Cognito
IAM
USER AUTH: SIGV4 / IAM

31. Mobile
apps
Admin Portal
Partner
Services
AWS Lambda
functions receive
Cognito Identity Id
of caller and
Identity Pool Id
API
Gateway
Amazon
Cognito
403 – Unauthorised from API GW
403 – Unauthorised from app
SigV4-signed Url
USER AUTH: SIGV4 / IAM

32. AMAZON API GATEWAY
Integrated security & SDK generation
D E V L O U N G E

33. Let’s test some code
D E V L O U N G E

34. • What are we looking for when we test Lambda functions?
• Asynchronous calls not returning
• Missing ‘completion’ by calling context.done() or context.callback()
• Timeouts
• Giving back resources like socket connections
• How can I test my Lambda functions?
• The same way you test standalone NodeJS/Java/Python/CSharp!
• Isolate your components/functions so they can be tested
• Consider TDD – start with testing before writing code
• Test your code’s business logic using local DynamoDB and
memcache to reduce reliance on network
TESTING LAMBDA FUNCTIONS
D E V L O U N G E

35. [Test]
function testSomething()
{
ASSERT(true);
// todo – I am too busy right now
return true;
}
TESTING ANTI-PATTERN!

36. • Amazon Device Farm
• Test on real iOS, Android and Fire OS devices in the cloud
• Test native apps or web apps
• Execute automated tests in popular automation frameworks:
• Appium (Java Junit, Java TestNG, Python – for web application testing)
• Calabash
• Espresso
• Junit
• XCTest
• KIF
• Robotium and more
TESTING MOBILE APPS
D E V L O U N G E

37. • Built-in Fuzz Test (Android & iOS)
• Randomly sends user interface events to devices and then reports results
• Built-in Explorer Test (Android)
• Crawls your app by analysing each screen and interacting as if it were an end user
• Takes screenshots as it explores
• Provide Device Farm with credentials so the test can log in
• View actionable test results
• Screenshots, videos, logs and performance data
• Integrate testing into your workflow
• Use the Device Farm API directly or make use of the
Jenkins plug-in or Gradle plug-in
TESTING MOBILE APPS
D E V L O U N G E

38. Visualisation with ElasticSearch
and graphing frameworks
D E V L O U N G E

39. • Amazon ElasticSearch – managed service
• No need to worry about infrastructure - *aaS!
• Script everything – the cluster… the schema... test data...
• Define your index mappings explicitly
(for example, timestamps and enums)
• Always secure access to your domain using a restrictive access policy!
• http-aws-es credential helper module on npm
VISUALISATION
D E V L O U N G E

40. CONNECTING TO ES WITH IAM CREDENTIALS
D E V L O U N G E

41. STATISTICS INDEX FORMAT – NEW BUTTON PRESS
D E V L O U N G E

42. STATISTICS INDEX FORMAT – TASK COMPLETED
D E V L O U N G E

43. ES AGGREGATIONS
D E V L O U N G E

44. • ElasticSearch Getting Started Guide
• www.elastic.co/guide/en/elasticsearch/reference/current/getting-started.html
• ElasticSearch on NodeJS
• elasticsearch module on npm
• http-aws-es credential helper module on npm
• AngularJS web UI framework
• angularjs.org
• Angular Chart Framework
• jtblin.github.io/angular-chart.js/
REFERENCES
D E V L O U N G E

45. • Grunt – the Javascript task runner
• gruntjs.com
• Helpful Grunt plug-ins for AWS
• grunt-aws-lambda module on npm
• grunt-aws module on npm
• Mocha test framework
• mochajs.org
REFERENCES
D E V L O U N G E

46. • Cognito JWT
• jsonwebtoken module on npm
• jwk-to-pem module on npm
• Render/decode JWT
• jwt.io
• AWS Code Samples on GitHub
• github.com/awslabs
• FireOS / Android viewer
• Vysor Chrome Extension
REFERENCES
D E V L O U N G E

47. Adam Larter
Principal Solutions Architect, Developer Specialist
Thank you!