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Aws Lambda for Java Architects - JavaOne -2016-09-19
Derek C. Ashmore gave a presentation on AWS Lambda for Java architects. He began with an introduction of himself and his background. The presentation covered what AWS Lambda is, how to develop Lambda functions in Java, tools to support Lambda development, using Lambdas for microservices, and answered chief complaints about Lambda. Ashmore provided implementation tips and pointed to additional resources for further reading on AWS Lambda.
Aws Lambda for Java Architects - JavaOne -2016-09-19
- 1. AWS Lambda forJava Architects Given by Derek C. Ashmore Sept 19, 2016 ©2016 Derek C. Ashmore, All Rights Reserved 1
- 2. Who am I? •Professional Geek since 1987 • Java/J2EE/Java EE since 1999 • Roles include: • Developer • Architect • Project Manager • DBA • System Admin ©2016 Derek C. Ashmore, All Rights Reserved 2
- 3. Discussion Resources • Thisslide deck – http://www.slideshare.net/derekashmore • Sample code on my Github – https://github.com/Derek-Ashmore/ • Sample Java AWS Lambda Source – https://github.com/Derek-Ashmore/AWSLambdaExamples • Slide deck has hyper-links! – Don’t bother writing down URLs ©2016 Derek C. Ashmore, All Rights Reserved 3
- 4. Agenda The “What” and “Why”of AWS Lambda Developing Lambda Supporting Lambda Lambda and Microservices Summary / Q&A ©2016 Derek C. Ashmore, All Rights Reserved 4
- 5. What are AWSLambdas? • You provide custom code -> AWS runs it – Java, Node.js, Python • Computing power with less management – AWS manages the hardware – AWS autoscales that hardware – AWS maintains that hardware • Lambdas are event driven – API Gateway (e.g. RESTful Web Service call) – Many more • Lambdas are stateless • Not to be confused with “Lambda Expressions” in Java 8 ©2016 Derek C. Ashmore, All Rights Reserved 5
- 6. Lambda Event Sources •API Gateway • SNS Messaging Subscriptions • Schedule • Storage writes – S3, DynamoDB, Kenesis ©2016 Derek C. Ashmore, All Rights Reserved 6 • SES Email receipt • Cloudwatch – Schedule, Events, log entries • Cognito (Security) • CloudFormation – Creation script
- 7. What’s the BusinessBenefit • Less Maintenance Hassle • Unlimited Parallelism • Current cost advantage – Don’t pay for idle – CPU cost currently lower • Free tier – 1 M executions and 400K compute seconds per month – Memory allocated determines allowed free-tier runtime • 20 cents per 1 M executions + memory/runtime cost – Administration cost • No O/S upgrades, server backups, etc. ©2016 Derek C. Ashmore, All Rights Reserved 7
- 8. There’s no freelunch • Less control over environment – Harder to tune – Memory and time limits on execution • No Java EE amenities – No connection pooling, session support, caching • Proprietary Interface – Potential Technical Lock-in • No Guarantee that AWS cost will be constant – Potential Business Risk • Modern version of CGI ©2016 Derek C. Ashmore, All Rights Reserved 8
- 9. Agenda The “What” and “Why”of AWS Lambda Developing Lambda Supporting Lambda Lambda and Microservices Summary / Q&A ©2016 Derek C. Ashmore, All Rights Reserved 9
- 10. Lambda Java API •RequestHandler interface • JSON marshalling of Request and Response • Execution Context • Deployment Zip Artifact – Typically one RequestHandler per Zip artifact ©2016 Derek C. Ashmore, All Rights Reserved 10
- 11. Lambda Request /Response Sample • Expose REST API that collects email addresses for a mailing list – https://scrubbed/prod/EmailCollector • Sample request/response ©2016 Derek C. Ashmore, All Rights Reserved 11
- 12. Implementing a RequestHandler •RequestHandler interface is generic. – POJOs represent the request and response – POJOs determine JSON request/response format – Execution Context class provided by AWS • This class specified when Lambda defined • Note the wrapping try/catch – Portion of the Context provided by AWS -> need more – AWS Does marshalling – ContextedRuntimeException from Apache Commons Lang3 • Note that the Lambda is thin -> Business logic is elsewhere • Sample is on GitHub (here) ©2016 Derek C. Ashmore, All Rights Reserved 12
- 13. Implementing a RequestHandler •RequestHandler interface is generic. – POJOs represent the request and response – POJOs determine JSON request/response format – Execution Context class provided by AWS • This class specified when Lambda defined • Note the wrapping try/catch – Portion of the Context provided by AWS -> need more – AWS Does marshalling – ContextedRuntimeException from Apache Commons Lang3 • Note that the Lambda is thin -> Business logic is elsewhere • Sample is on GitHub (here) ©2016 Derek C. Ashmore, All Rights Reserved 13
- 14. Implementing a RequestHandler •RequestHandler interface is generic. – POJOs represent the request and response – POJOs determine JSON request/response format – Execution Context class provided by AWS • This class specified when Lambda defined • Note the wrapping try/catch – Portion of the Context provided by AWS -> need more – AWS Does marshalling – ContextedRuntimeException from Apache Commons Lang3 • Note that the Lambda is thin -> Business logic is elsewhere • Sample is on GitHub (here) ©2016 Derek C. Ashmore, All Rights Reserved 14
- 15. What’s in theContext? • Execution Context provided by AWS • Contains: – AWS Request ID -> Get logs for specific request – Function name, version, arn – Cognito identity – Remaining time/memory – Mobile client information (AWS Mobile SDK) • Environment name/value map • Custom name/value map ©2016 Derek C. Ashmore, All Rights Reserved 15
- 16. Resource Support • Java8 Runtime -> – you can configure memory available • Log4J logging available – Viewable/searchable in Cloudwatch logs – Custom Log4J Appender provided • Third party jars can be included – Including AWS SDK for AWS Tasks (executing other Lambdas) – JDBC Drivers – HttpClient or Apache CXF • Keep in Mind – You create/destroy all database connections • No connection pooling (Lambdas are stateless) – Caching APIs have limited benefit (Lambdas are stateless) – No Remote Debug capability ©2016 Derek C. Ashmore, All Rights Reserved 16
- 17. Lambda Deployment Package •Zip Organization – Root is in the classpath – Lib contains 3rd party jars • Maven example here – Need maven-dependency-plugin, maven-antrun-plugin ©2016 Derek C. Ashmore, All Rights Reserved 17
- 18. API Gateway • ExposesLambdas as a RESTful Web Service – Can be publicly available or part of a secured private microservice library ©2016 Derek C. Ashmore, All Rights Reserved 18
- 19. Gateway Lambda Integration ©2016Derek C. Ashmore, All Rights Reserved 19 • Integrations do basic transformations – Map headers and parameters to Lambda request fields
- 20. Gateway Integration Example ©2016Derek C. Ashmore, All Rights Reserved 20
- 21. Gateway Models ©2016 DerekC. Ashmore, All Rights Reserved 21
- 22. Gateway Models (con’t) •Jackson can generate the Json schema needed as a Model – No Mavin plugin for this – Example Java code to generate (here) – Example Mavin pom generating on build (here) ©2016 Derek C. Ashmore, All Rights Reserved 22
- 23. Lambdas and SNSTopics • Lambdas can subscribe to SNS Publish/subscribe topics • Request Message is type SNSEvent ©2016 Derek C. Ashmore, All Rights Reserved 23
- 24. Lambdas can bescheduled • Lambda executions can be scheduled through CloudWatch – Cron expressions supported ©2016 Derek C. Ashmore, All Rights Reserved 24
- 25. Tooling Gotchas • APIGateway requires client with Server Name Indication (SNI) support – Most recent SoapUI does not (reference) – Had to write my own test client using Httpclient 4.2 or above ©2016 Derek C. Ashmore, All Rights Reserved 25
- 26. Agenda The “What” and “Why”of AWS Lambda Developing Lambda Supporting Lambda Lambda and Microservices Summary / Q&A ©2016 Derek C. Ashmore, All Rights Reserved 26
- 27. Versioning Support • Lambdaversioning and aliases – Aliases are labels (e.g. PROD, TEST, DEV) that can be reassigned to different versions. – Versions are unique an can’t be changed. • S3 versioning possible for Lambda Zip artifacts • You need a correlation between source control and Lambda version – Possibilities • Tag all Lambda versions in source control and include the Lambda version number • Breadcrumbs in the deployed Zip that describe the specific source control change number used for the build ©2016 Derek C. Ashmore, All Rights Reserved 27
- 28. Lifecycle Environment Support •Configuration Support – Baked into the deployment zip • You can’t just move the zips from environment to environment • Spring profiles not an option as you don’t control JVM parms – API Gateway does have staging variables • No Remote Debug Support ©2016 Derek C. Ashmore, All Rights Reserved 28
- 29. Automated Deployment Options •Nothing out of the box • One possibility – Load Lambda function from S3 bucket – Jenkins plugin to load build artifacts to S3 • https://wiki.jenkins-ci.org/display/JENKINS/S3+Plugin – Use AWS CLI to Manage lambda publishing and aliases ©2016 Derek C. Ashmore, All Rights Reserved 29
- 30. Performance • Start-up Time– Python, Node.js, Java – Berezovsky performance test • Throughput – Java and Node.js – Both have a JIT – DZone comparison here – Close enough that other factors would likely guide your language choice ©2016 Derek C. Ashmore, All Rights Reserved 30
- 31. Agenda The “What” and “Why”of AWS Lambda Developing Lambda Supporting Lambda Lambda and Microservices Summary / Q&A ©2016 Derek C. Ashmore, All Rights Reserved 31
- 32. Lambdas and Microservices ©2016Derek C. Ashmore, All Rights Reserved 32
- 33. Using Lambdas asMicroservices • Lambda / API Gateway is a deployment option for microservices – No differences in design principles • Single purpose • Self-contained – Still design for failure • Don’t “assume” that Lambda outages can’t happen – A Lambda might need external resources that aren’t available • Off Limits: Coding patterns that use state – Lambdas must be stateless – Fail fast patterns • Service Call Mediator • Circuit Breaker – Performance Patterns • Expiring Cache (API Gateway allows request caching) ©2016 Derek C. Ashmore, All Rights Reserved 33
- 34. Back-ends for Front-ends ©2015Derek C. Ashmore, All Rights Reserved 34
- 35. Retry Pattern ©2015 DerekC. Ashmore, All Rights Reserved 35 • Best for asynchronous tasks • Limit the number of tries • You must stay under your Lambda execution time limit! • Use sleep interval between tries • Only addresses temporary outages • Sample Retry Pattern implementation here. • Tooling Support: – Apache CXF supports Retry – Spring Batch RetryTemplate – Apache HttpClient (Example here)
- 36. Dispatch via Messaging ©2015Derek C. Ashmore, All Rights Reserved 36 • Place work instruction on persistent queue • If receivers are down, work stacks in queue • Work throttled by number of receivers • Queue can be SES, JMS or AMQP • Tooling Support: – JMS Api (easy API – many use natively) – Spring JMSTemplate or RabbitTemplate (producer)
- 37. Custom Rollback ©2015 DerekC. Ashmore, All Rights Reserved 37
- 38. Custom Rollback (continued) •Reverses a transaction previously posted • Only use this for multi-service transactions – Keeping the transaction within one service is preferred • This pattern is completely custom – No special product support available • More information here ©2015 Derek C. Ashmore, All Rights Reserved 38
- 39. Contract Testing • Criticalfor MS architectures – Contract changes can break other services – Bulkhead for rogue developers – Makes individual services more disposable • Consumer-based testing • Tooling support – Apache HttpClient (4.2 or above) ©2015 Derek C. Ashmore, All Rights Reserved 39
- 40. Agenda The “What” and “Why”of AWS Lambda Developing Lambda Supporting Lambda Lambda and Microservices Summary / Q&A ©2016 Derek C. Ashmore, All Rights Reserved 40
- 41. Chief Complaints • Documentationleaves a lot to be desired – This is an understatement. – For Java Lambdas, you are almost on your own. • Lambda start-up time not consistent – Sometimes long start-up time for JVM – Python is the fastest • Optimizations that depend on state aren’t as easy – You would have to persist that state • This would have it’s own concurrency and performance issues ©2016 Derek C. Ashmore, All Rights Reserved 41
- 42. Implementation Tips • Separationof Concerns – Keep Lambda code separate from business logic • Might want to change vendors someday – Keep AWS SDK code separate from business logic • Same reason – Invoke other Lambdas through the API Gateway, not directly through the AWS SDK • Same reason – Keep Business Logic locally runnable/debuggable • Remote debug isn’t yet possible • Ensure you can always tie AWS Request Id to your business transaction – Need a way to gather logs from a complete business transactions and the many services it might use – All invocations get unique AWS request Ids • For example, lambda invokes other lambdas – Configure log4j layout to include AWS Request Id (example) ©2016 Derek C. Ashmore, All Rights Reserved 42
- 43. Lambda and theGartner Hype Cycle ©2016 Derek C. Ashmore, All Rights Reserved 43
- 44. Further Reading • Thisslide deck – http://www.slideshare.net/derekashmore • AWS Lambda Reading List – http://www.derekashmore.com/2016/04/aws-lambda-reading-list.html ©2016 Derek C. Ashmore, All Rights Reserved 44
- 45. Questions? • Derek Ashmore: –Blog: www.derekashmore.com – LinkedIn: www.linkedin.com/in/derekashmore – Twitter: https://twitter.com/Derek_Ashmore – GitHub: https://github.com/Derek-Ashmore – Book: http://dvtpress.com/ ©2016 Derek C. Ashmore, All Rights Reserved 45