My talk on Jozi JUG about MicroServices on June 24th 2013. http://www.meetup.com/Jozi-JUG/events/118708272/

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