AWS Lambda for Architects - Chicago Coder Conference -2016-06-07

Who am I? • Professional Geek since 1987 • Java/J2EE/Java EE since 1999 • Cloud since 2012 • Roles include: • Architect • Developer • Project Manager • DBA • System Admin ©2016 Derek C. Ashmore, All Rights Reserved 2

Discussion Resources • This slide 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

What are AWS Lambdas? • 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

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

What’s the Business Benefit • 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

There’s no free lunch • Less control over environment – Harder to tune – Memory and time limits on execution • Few Environment 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

Lambda API • Create a Request Handler – Inputs are • Event input (user input arguments) • Context input (info about execution environment) – Outputs are user decided • 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

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

Java Request Handler Example • 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) • Node.js and Python similar ©2016 Derek C. Ashmore, All Rights Reserved 12

What’s in the Context? • 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 13

Resource Support • Runtime Support – you can configure memory and max run time available – Java  Java 8; AWS SDK jar must be included in your deployment – Node.js  AWS SDK for Node.js preinstalled – Python  AWS SDK for Python preinstalled • All logging viewable/searchable in Cloudwatch logs – Node.js and Python log to the console – Java uses customer Log4J Appender • Third party jars/libraries can be included – Including AWS SDK for AWS Tasks (executing other Lambdas) – Database Drivers – Web service libraries • 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 14

Lambda Deployment Package • Zip Organization (Java example) – 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 15

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 19

Tooling Gotchas • API Gateway 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 22

Versioning Support • Lambda versioning 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 24

Lifecycle Environment Support • Configuration Support – Baked into the deployment zip • You can’t just move the zips from environment to environment • Java 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 25

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 26

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 27

Using Lambdas as Microservices • 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 30

Retry Pattern ©2015 Derek C. Ashmore, All Rights Reserved 32 • 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)

Dispatch via Messaging ©2015 Derek C. Ashmore, All Rights Reserved 33 • 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)

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 35

Contract Testing • Critical for 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 36

Chief Complaints • Documentation leaves 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 38

Implementation Tips • Separation of 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 (Java) to include AWS Request Id (example) – Node.js and Python logs have request id automatically ©2016 Derek C. Ashmore, All Rights Reserved 39

Further Reading • This slide 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 41

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 42

AWS Lambda for Architects - Chicago Coder Conference -2016-06-07

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AWS Lambda for Architects - Chicago Coder Conference -2016-06-07