Apache Sling as a Microservices Gateway --- Microservices are definitely the hot topic _du jour_ . Everyone ( and their dog ) is using microservices or migrating towards them. However, there is a gap between the enthusiam for microservices and the ability to create and maintain the infrastructure and culture to effectively use microservices. Apache Sling is an innovative web framework built on top of the Java Content Repository (JCR), that uses OSGi for its component model and fosters RESTful application design. And, as we will see, it is also perfect match for a microservices gateway. In this talk we will review the pros and cons of microservices and monoliths, and look for middle road that smaller organisations that follow to use services productively. One of the approaches we will outline and demo is an API gateway built on top of Apache Sling, used to adress the cross-cutting concerns that would otherwise be reimplemented by all microservices.

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Apache Sling as a Microservices Gateway
Apache Sling as a Microservices Gateway
Robert Munteanu, Adobe Systems
Voxxed Days Bucharest 2016

2. http://robert.muntea.nu @rombert
Who I am

$DAYJOB

Adobe Experience
Manager
 Apache Sling
 Apache Jackrabbit
 Apache Felix

Open Source

Apache Sling

MantisBT

Mylyn Connector for
MantisBT

Mylyn Connector for Review
Board

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Agenda
●
Of microservices and monoliths
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Advantages of microservices
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Advantages of monoliths
●
A middle ground?
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Apache Sling primer
●
Meeting Barry
●
Demo Application
●
Conclusion

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Agenda
●
Of microservices and monoliths
●
Advantages of microservices
●
Advantages of monoliths
●
A middle ground?
●
Apache Sling primer
●
Meeting Barry
●
Demo Application
●
Conclusion

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Advantages of microservices

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Advantages of microservices – best tool for the job

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Advantages of microservices – always think of failures

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Advantages of microservices – simpler scaling

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Advantages of microservices – faster deployment

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Advantages of microservices – different level of reusability

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Agenda
●
Of microservices and monoliths
●
Advantages of microservices
●
Advantages of monoliths
●
A middle ground?
●
Apache Sling primer
●
Meeting Barry
●
Demo Application
●
Conclusion

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Advantages of monoliths – crowdsourced wisdom

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Advantages of monoliths – less distributed computing
1. The network is reliable
2. Latency is zero
3. Bandwidth is infinite
4. The network is secure
5. Topology doesn't change
6. There is one administrator
7. Transport cost is zero
8. The network is homogeneous
The Eight Fallacies of Distributed Computing, Peter Deutsch, 1994

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Advantages of monoliths – Latency/Bandwidth

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Advantages of monoliths – Security

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Advantages of monoliths – less operations overhead

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Advantages of monoliths – less operations overhead

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Advantages of monoliths – better code reuse

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Advantages of monoliths – simpler availabilty

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Advantages of monoliths – easier service discovery

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Advantages of monoliths – easier troubleshooting

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Agenda
●
Of microservices and monoliths
●
Advantages of microservices
●
Advantages of monoliths
●
A middle ground?
●
Apache Sling primer
●
Meeting Barry
●
Demo Application
●
Conclusion

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A middle ground – value proposition
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What are you trying to solve with microservices?
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What level of technical diversity does your
organisation have?
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Are you confortable with partially embracing
microservices?

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A middle ground – using an API gateway
Provides:
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Authentication
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Authorization
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KPIs
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Circuit breakers
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API adaptions
Must be:
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Lightweight
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Stateless
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Extensible

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Agenda
●
Of microservices and monoliths
●
Advantages of microservices
●
Advantages of monoliths
●
A middle ground?
●
Apache Sling primer
●
Meeting Barry
●
Demo Application
●
Conclusion

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Apache Sling – Brief History
2007
Incubation
2009
TLP
2015
Version 8
200x
Pre-Apache

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Apache Sling – Code Statistics

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Apache Sling – Contributor activity

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Apache Sling – Value proposition
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Content-oriented
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RESTful
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Lightweight
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OSGi-powered
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Easily deployable

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Apache Sling – Repository view of the world
[sling/redirect]
[sling/redirect]
[blog/welcome]
[blog/page]
/
/content
/content/blog
/content/blog/hello-world

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Apache Sling – gateway through ResourceProviders

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Apache Sling – gateway through ResourceProviders
/
/customers
/inventory
/orders
Customer
µService
Inventory
µService
Orders
µService
Logging
KIPMeasurement
CircuitBreakers
Authentication
Authorization

33. http://robert.muntea.nu @rombert
Agenda
●
Of microservices and monoliths
●
Advantages of microservices
●
Advantages of monoliths
●
A middle ground?
●
Apache Sling primer
●
Meeting Barry
●
Demo Application
●
Conclusion

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Meeting Barry

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Agenda
●
Of microservices and monoliths
●
Advantages of microservices
●
Advantages of monoliths
●
A middle ground?
●
Apache Sling primer
●
Meeting Barry
●
Demo Application
●
Conclusion

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Demo application - overview

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Demo Application - authentication

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Demo Application - JWT

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Demo Application – Actual demo!!!!1oneone

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Agenda
●
Of microservices and monoliths
●
Advantages of microservices
●
Advantages of monoliths
●
A middle ground?
●
Apache Sling primer
●
Meeting Barry
●
Demo Application
●
Conclusion

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Conclusions – Apache Sling
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Eventing, Thread Pooling, Job Management,
Caching
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Scripting: Groovy, Scala, JSP, Sightly, Java, Ruby,
Thymeleaf
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Flexible resource rendering with resource types
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Very extensible due to being internally powered by
OSGi – most extension points available to clients

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Conclusions – Microservices
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Microservices are a useful tool, but make sure you
understand the tradeoffs
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Microservices are not an all-or-nothing proposition,
pick what is best for your organisation
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An API gateway can bring a lot of value to a
microservices deployment
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Try Apache Sling today

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Resources
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Apache Sling – https://sling.apache.org
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Apache Jackrabbit
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https://jackrabbit.apache.org
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http://jackrabbit.apache.org/oak/
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JWT – https://jwt.io
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Netflix Hystrix - https://github.com/Netflix/Hystrix