The purpose of Serverless is to focus on writing the code that delivers business value and offload undifferentiated heavy lifting to the Cloud providers or SaaS vendors of your choice. Today’s code quickly becomes tomorrow’s technical debt even if you meet the perfect decision. The less you own, the better it is from the maintainability point of view. In this talk I will go through examples of the various Serverless architectures on AWS where you glue together different Serverless managed services relying mostly on configuration, significantly reducing the amount of the code written to perform the task. Own less, build more!

1. Writing less code with Serverless on
Vadym Kazulkin, ip.labs, 1 February 2022

2. Contact
Vadym Kazulkin
ip.labs GmbH Bonn, Germany
Co-Organizer of the Java User Group Bonn
and Serverless Bonn Meetup
v.kazulkin@gmail.com
@VKazulkin
https://www.linkedin.com/in/vadymkazulkin
https://www.iplabs.de/

3. ip.labs
https://www.iplabs.de/

4. Agenda
• Challenges of the software development
• Serverless and its value proposition
• Dive deeper into “own less, build more” and
“lower technical debt” aspects
• Examples of AWS Serverless services and architectures for
writing less code
• How to be successful with Serverless

5. Let’s talk about the
challenges of the software
development in general
first

6. Cognitive Load –
the total amount of mental
effort being used in the working
memory
• Intrinsic
• Extraneous
• Germane

7. Cognitive Load
• Intrinsic
• How to write a Java class or use a framework
(Spring)
• Extraneous
• Germane

8. • Intrinsic
• Extraneous
• How to automate tests (unit, integration, end-to-end, web, desktop, mobile)
• How to build, package, deploy and run my application
• How to configure monitoring, alerting, auto-scaling, logging and tracing
• How to operate and maintain infrastructure
• How to build-in fault-tolerance and resiliency
• How to make the hardware, networking and application secure
• Germane
Cognitive Load

9. • Intrinsic
• Extraneous
• Germane
• Domain Knowledge (payment, e-commerce)
• Business processes and workflows
Cognitive Load

10. • Intrinsic ->
become fluent in it
• Extraneous ->
minimize amount of what we
implement/operate/support/own by ourselves
• Germane ->
minimize amount of what we have to implement
by ourselves
Cognitive Load

11. What our boss wants from us?
… that we are productive

12. Productivity
We are productive if we regularly ship products,
which are successfully used by our customers

13. What is holding us back from
being productive?
Technical Debt - reflects the implied cost
of additional rework caused by choosing an
easy (limited) solution now instead of using
a better approach that would take longer
”The Cost of Poor Quality Software in the US: A 2018 Report”
https://www.it-cisq.org/the-cost-of-poor-quality-software-in-the-us-a-2018-report/The-Cost-of-Poor-Quality-Software-in-the-US-2018-Report.pdf

14. Technical Debt
• Even a perfect solution can become the
technical debt over the time
• Version of programming language comes
out of support (Java 8, JS Frameworks)
• Security considerations forces us to
upgrade one of our dependencies (library
or web application server version)
• One of our dependencies (e.g. to open
source project) is discontinued

15. Think of what can happen to your software
over the entire life cycle of our product
Technical Debt

16. • is related to amount of code written
• is related to amount of dependencies used
• open source projects, programming
languages, databases, (web) application
servers
Technical Debt

17. Legacy Systems are systems that can’t
evolve
”The Cost of Poor Quality Software in the US: A 2018 Report”
https://www.it-cisq.org/the-cost-of-poor-quality-software-in-the-us-a-2018-report/The-Cost-of-Poor-Quality-Software-in-the-US-2018-Report.pdf
Legacy System

18. Evolutionary Architecture–
supports guided, incremental
change across multiple
dimensions
• Incremental change
• Appropriate architectural coupling
• Fitness functions
”Architectural Coupling” https://learning.oreilly.com/library/view/building-evolutionary-architectures/9781491986356/ch04.html

19. Evolutionary Architecture–
Fitness functions
• Source code metrics (such as measuring
cyclomatic complexity)
• Unit tests (% of coverage and % of success)
• Performance metrics(such as API latency or
throughput)
• Security (encryption at rest, e.g. checking that all S3
buckets have encryption enabled, or automatic key rotation
for all external APIs, with tools such as the AWS Secrets
Manager)
• ArchUnit, Sonar, CI/CD Tools
• CodeCommit,…CodeDeploy, Jenkins
Danilo Poccia „ Serverless + Evolutionary Architectures + Safe Deployments = Speed in the Right Direction”
https://blog.usejournal.com/serverless-evolutionary-architectures-safe-deployments-speed-in-the-right-direction-7b4b01e27254

20. Serverless

21. The Value Proposition of
Serverless
But let’s talk about of Total Cost of Ownership of
the Serverless paradigm

22. TCO Full Picture
No Infrastructure
Operation and
Maintenance
Auto Scaling and
Fault Tolerance
Built in
Own less,
build more
Lower technical
debt
Faster Time to
Market
Forrest Brazeal „The Business Case For Serverless” https://www.trek10.com/blog/business-case-for-serverless
Focus on Business
Value and Innovation

23. Own less, build more
By heavily relying on the
managed Serverless services
you
• Can do more with the
same amount of people
• Can more easily evolve
your architecture
Lower technical debt
• Whatever code you write today is always
tomorrow’s technical debt © Paul
Johnston
• Less code means lower technical debt
• Less code means less code maintenance
• Time and effort required for maintaining
the solution over its whole lifecycle is by
far much more than for developing it
Jeff Atwood „The Best Code is No Code At All” https://blog.codinghorror.com/the-best-code-is-no-code-at-all/
Paul Johnston “Cloud 2.0: Code is no longer King — Serverless has dethroned it”
https://medium.com/@PaulDJohnston/cloud-2-0-code-is-no-longer-king-serverless-has-dethroned-it-c6dc955db9d5

24. • Write fewer Lambda functions
• use more direct service integrations in case the Lambda only calls the
Service itself
How to write less code with
AWS Serverless services 1/2

25. Less Lambda functions means less:
• code to write, test, run and maintain
• CI/CD (deploy, rollback strategies) to maintain
• Infrastructure as a Code (IAM policies, permission) to write and test
• cold-start worries
• point of failures and retries
• security concerns
• worries about Lambda limits (e.g. concurrency settings per AWS account)
• spending on Lambda, CloudWatch and 3rd party SaaS on (AWS) (monthly) bill
Sheen Brisals “Don’t wait for Functionless. Write less Functions instead”
https://medium.com/lego-engineering/dont-wait-for-functionless-write-less-functions-instead-8f2c331cd651

26. • Write fewer Lambda functions
• use more direct service integrations in case the Lambda only calls the
Service itself
• Write less Infrastructure as a Code by using AWS Services/Frameworks
which provide meaningful abstractions, including managed I/CD
• AWS Amplify and Serverless Cloud
How to write less code with
AWS Serverless services 2/2

27. Examples how to write less code with
AWS Serverless services
• API Gateway Service Integration
• HTTP APIs Storage-First Service
Integration
• Step Functions Service Integration
• Step Functions Workflow Studio
• EventBridge with Service Integrations
and API Destinations
• Event Bridge Filtering and Routing
• Filtering for Lambda Functions
• NoSQL Workbench for DynamoDB
• SNS message filtering and native
integration between SNS and
Kinesis Data Firehose
• Amplify Framework
• Serverless Cloud Preview

28. Sheen Brisals “Don’t wait for Functionless. Write less Functions instead”
https://medium.com/lego-engineering/dont-wait-for-functionless-write-less-functions-instead-8f2c331cd651
API Gateway Service Integration

29. API Gateway Service Integration with
Dynamo DB : Example ID generator 1/2
Sheen Brisals “Sequence Numbering in Serverless via API Gateway” https://medium.com/lego-engineering/sequence-numbering-in-serverless-via-api-gateway-40e5f6c83e93
Zac Charles “Quickly Build and Debug AppSync & API Gateway Mapping Templates” https://mappingtool.dev/

30. API Gateway Service Integration with
Dynamo DB : Example ID generator 2/2
Sheen Brisals “Sequence Numbering in Serverless via API Gateway” https://medium.com/lego-engineering/sequence-numbering-in-serverless-via-api-gateway-40e5f6c83e93
Zac Charles “Quickly Build and Debug AppSync & API Gateway Mapping Templates” https://mappingtool.dev/

31. Eric Johnson “https://aws.amazon.com/de/blogs/compute/building-storage-first-applications-with-http-apis-service-integrations/”
HTTP APIs Storage-First Service
Integration
• Event Bridge
• Kinesis Data Streams
• SQS
• AppConfig
• Step Functions

32. Using Service Integrations with EventBridge
“Amazon EventBridge” https://aws.amazon.com/eventbridge/

33. Using Service Integrations with
EventBridge /Put Targerts
“Amazon EventBridge Put Targets” https://docs.aws.amazon.com/eventbridge/latest/APIReference/API_PutTargets.html

34. Using API Destinations with EventBridge
“Amazon EventBridge” https://aws.amazon.com/eventbridge/

35. Using API Destinations with EventBridge
“Using API destinations with Amazon EventBridge”
https://aws.amazon.com/de/blogs/compute/using-api-destinations-with-amazon-eventbridge/

36. EventBridge Filtering and Routing
“Reducing custom code by using advanced rules in Amazon EventBridge”
https://aws.amazon.com/de/blogs/compute/reducing-custom-code-by-using-advanced-rules-in-amazon-eventbridge/

37. S3 Event Notifications with EventBridge
https://aws.amazon.com/blogs/aws/new-use-amazon-s3-event-notifications-with-amazon-eventbridge/

38. SNS Message Filtering
https://aws.amazon.com/blogs/compute/simplify-pubsub-messaging-with-amazon-sns-message-filtering/

39. Native integration between SNS and
Kinesis Data Firehose
https://aws.amazon.com/de/blogs/compute/introducing-message-archiving-and-analytics-for-amazon-sns/

40. Step Functions Service Integration
“Service Integrations with AWS Step Functions” https://docs.aws.amazon.com/step-functions/latest/dg/concepts-service-integrations.html

41. AWS Step Functions Supports 200
AWS Services
https://aws.amazon.com/de/blogs/aws/now-aws-step-functions-supports-200-aws-services-to-enable-easier-workflow-automation/
arn:aws:states:::
aws-sdk:serviceName:apiAction.
<serviceIntegrationPattern>

42. Step Functions Workflow Studio – A Low-Code
Visual Tool for Building State Machines
“AWS Step Functions Workflow Studio”
https://aws.amazon.com/de/blogs/aws/new-aws-step-functions-workflow-studio-a-low-code-visual-tool-for-building-state-machines/

43. Filtering event sources for Lambda
functions
https://aws.amazon.com/blogs/compute/filtering-event-sources-for-aws-lambda-functions/
https://dev.to/aws-builders/trigger-lambda-functions-with-event-filtering-2pnb
Filtering is supported for the following event sources:
• Kinesis Data Streams
• DynamoDB Streams
• Amazon SQS

44. NoSQL Workbench for DynamoDB
https://aws.amazon.com/dynamodb/nosql-workbench/
Data Modeling Data Visualization Operation Building

45. Export DynamoDB Table Data to S3
https://aws.amazon.com/de/blogs/aws/new-export-amazon-dynamodb-table-data-to-data-lake-amazon-s3/

46. Amplify
“Amazon Amplify” https://aws.amazon.com/amplify
Amplify supports :
• web frameworks including JavaScript, React, Angular, Vue, Next.js
• mobile platforms including Android, iOS, React Native, Ionic, Flutter

47. Amplify and Admin GUI
https://docs.amplify.aws/console/adminui/intro#access-outside-the-aws-management-console/

48. AWS Amplify managed CI/CD
https://towardsaws.com/step-by-step-guide-to-deploy-your-web-application-with-auto-ci-cd-pipeline-using-aws-amplify-a87712756c2

49. Serverless Cloud Preview
https://www.serverless.com/blog/introducing-serverless-cloud-public-preview

50. Serverless Cloud Preview
https://www.serverless.com/blog/introducing-serverless-cloud-public-preview

51. Serverless Cloud Preview
https://www.serverless.com/blog/how-serverless-cloud-works-part-1

52. Serverless Cloud Preview
https://www.serverless.com/blog/introducing-serverless-cloud-public-preview

53. Common patterns
• Direct service integrations to reduce the amount of code written
• API Gateway, HTTP API, Step Functions, EventBridge, SNS,
Amplify
• Visual Studio/Tools to reduce the cognitive load
• Step Functions, Amplify, DynamoDB
• Automated CI/CD to focus on the business logic
• Amplify, SAM
• First steps in interpreting Infrastructure from Code
• Serverless Cloud

54. Focus on Business Value

55. Using Serverless ecosystem will
with the right engineering practices in place will significantly reduce
• extraneous and germane cognitive load
• the amount of code written
• the amount of dependencies (no execution runtime and web application server to
take care of)

56. Reducing dependencies doesn’t mean that you own nothing (you still
own things, but in general less)
• Lambda language runtime version will be retired from time to time
• Node.js <10.x, Java 8 runtime migration to Amazon Corretto
• Aurora with PostgreSQL/MySQL compatibilities will force you to
upgrade database version behind
• Retiring PostgreSQL version 9.6
plan and execute upgrades continuously and iteratively
Word of caution about the
Serverless ecosystem

57. How to be successful with Serverless

58. How to measure success
Let’s focus on software delivery and operational performance
(how to do the things right)
• Provide the managers and executives metrics, that we’re on the right path
• See from the developer’s perspective how to achieve it and improve
It’s also important to the right thing!

59. How to measure success
See DORA State of DevOps 2018-2019 Reports

60. Software Delivery and
Operational Performance
See DORA State of DevOps 2018-2019 Reports

61. Wardley Maps
Simon Wardley https://www.slideshare.net/swardley/why-the-fuss-about-serverless-88107645
Co-evolution of practices
to become productive with
Serverless

62. Co-evolution of practices with
Serverless 1/2
• True DevOps
• Complete infrastructure automation
• Chaos Engineering
• FinDev responsibilities in the teams
Sheen Brisals “Why the ‘WHY’ matters more than the ‘WHAT’ in Serverless!”
https://medium.com/lego-engineering/why-the-why-matters-more-than-the-what-in-serverless-2ef56c397962
DevOps Topologies: https://web.devopstopologies.com/

63. • Each team or even developer can have its own
(AWS test) account per feature or service
• Only minimal local testing (quick functional tests)
• Adopt “testing in production”
Michael Bryzek “What do you know about testing in production?” https://www.youtube.com/watch?v=z-ATZTUgaAo
Co-evolution of practices with
Serverless 2/2

65. www.iplabs.de
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