OSGi Community Event 2016 Presentation by Robert Munteanu (Adobe Systems Inc) Microservices are definitely the hot topic du jour . Everyone ( and their dog ) is using microservices or migrating towards them. To make things more interesting, the OSGi community has been talking about microservices for 6 years now, so now we have two clashing definitions of the term. Besides the dreaded monolith and the famed microservices-based architecture there is plenty of room for a middle ground, where an API gateway mediates between a host of microservices and their consumers. Such a gateway solves multiple cross-cutting concerns, such as authentication, API standardisation, logging and decoupling the API evolution. As it turns out, OSGi is an ideal setting for building such an application. The API gateway implementation demoed is based on Apache Sling – 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. Although we will use Apache Sling for examples, previous knowledge of Sling or its components is not required.

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Of Microservices and Microservices
Of Microservices and Microservices
Robert Munteanu, Adobe Systems
OSGi Community Event 2016

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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
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Microservices and monoliths
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Microservices and microservices
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A middle ground?
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Apache Sling primer
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Demo Application
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Conclusion

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Agenda
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Microservices and monoliths
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Microservices and microservices
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A middle ground?
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Apache Sling primer
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Demo Application
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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 – different level of reusability

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Advantages of microservices – faster deployment

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Advantages of microservices – faster delivery
Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8
Release Release Release
Week 1h Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8
Search
Catalogue
Payment
Payment Search
Payment
Catalogue
Payment
Search
Payment
Payment Search
Catalogue
Payment
Payment

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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 availability
Ordering
Search
Catalogue
User Preferences

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Advantages of monoliths – easier service discovery

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Advantages of monoliths – easier troubleshooting

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Agenda
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Microservices and monoliths
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Microservices and microservices
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A middle ground?
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Apache Sling primer
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Demo Application
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Conclusion

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Microservices and microservices

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How to choose?
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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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Agenda
●
Microservices and monoliths
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Microservices and microservices
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A middle ground?
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Apache Sling primer
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Demo Application
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Conclusion

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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
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Microservices and monoliths
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Microservices and microservices
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A middle ground?
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Apache Sling primer
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Demo Application
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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

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Agenda
●
Microservices and monoliths
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Microservices and microservices
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A middle ground?
●
Apache Sling primer
●
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
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Microservices and monoliths
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Microservices and microservices
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A middle ground?
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Apache Sling primer
●
Demo Application
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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