Microservices - an intro

My talk on Jozi JUG about MicroServices on June 24th 2013.

Transcript

1. Micro Services
2. Prasanna N Venkatesan Developer with ThoughtWorks http://prasans.info/blog @pvenk
3. Expect for…
4. Expect for… •  What are Micro services? •  Why we need a new pattern? •  Implementing a Micro Service •  When to use Micro Services •  Implications of using Micro Services
5. Write programs that do one thing and do it well.
6. Micro Services should be… Small • aka Simple • In terms of LOC. • In terms of memory footprint.
7. Micro Services should be… Portable Should be independent to deploy and run
8. Micro Services should be… Performs one thing Adding many functionality to one service will break the other 2 characteristics.
9. Move the complexity to Infrastructure We've  pushed  a  lot  of  the  old  applica2on  complexity  down  to  infrastructure  level.   We  are  no  longer  bound  to  a  single  stack  or  language.      
10. Micro Services A new Paradigm?
11. Small is beautiful Make each program do one thing well. Build a prototype as soon as possible. Choose portability over efficiency. Use software leverage to your advantage. Make every program as filter. UNIX Philosophy
12. Consumer-Driven Contracts Read  more  on:  h?p://mar2nfowler.com/ar2cles/consumerDrivenContracts.html  
14. • Provider Contracts • Consumer Contracts • Consumer Driven Contracts
15. •  Closed and complete •  Singular and non­authoritative •  Bounded stability and immutability
16. Domain Driven Design
17. •  Project's  primary  focus  on  the  core  domain   and  domain  logic.   •  Complex  designs  based  on  a  model  of  the   domain.   •  Itera2vely  refine  a  conceptual  model  that   addresses  par2cular  domain  problems.  
18. Communication       •  Mostly over HTTP and pass JSON between services. •  If serialization or de-serialization is expensive try something like ProtoBuf/MessagePack •  ProtoBuf - Google uses Protocol Buffers for almost all of its internal RPC protocols and file formats.
19. Monitoring •  More possibility of small services to just fail and fade away. •  Make sure services are running always •  Monitor usage and increase instances
20. Monitoring Tools
21. Testing Strategy •  Tes2ng  Micro  Services  are  not  so  cri2cal.   •  Preferably  have  health-­‐check  tests    in  CI.  
22. Where to use Micro Services •  Independent, small process worthy to try out in different stack. •  Don’t want to break a legacy system.
23. Implications •  Understanding how everything fits together •  Deployment •  Interactions between components •  Duplication of code across the services