MicroServices - How Do I Build Them - DundeePHP August 2016

A lightning overview and how some handy tips I've learned for building services locally

Transcript

1. Microservices What Are They? How Do I Build Them?
2. $(whoami) • Scott Pringle • Software Engineer • Microservices Advocate
3. What are they? Software design architecture of separating an application into a suite of small, independent services. Independent applications with no dependencies on any other services. Exposed via a pre-defined API for external consumers
4. Advantages
5. Smaller Apps & Teams • The less your app has to do, the less complex it (should) be • Easier to understand the purpose of the code • Separate teams based on service boundaries • Manage knowledge within teams easier • Designate internal leaders to manage workflow
6. Testability • The more defined your context is, the easier it is to test • Test suite will be smaller and quicker to run • Unit and Integration tests are fast - use them
7. Deployability • Only deploy the service that’s changed • Deploy with confidence
8. Polyglotism • Every service can be written in any language • Use the tools that are right for the job • Can result in complex systems with too much variation - Proceed with caution
9. Redundancy • Both an advantage and disadvantage • Consumers need to be redundant to handle a service not working • Should result in better uptime for customer-facing applications
10. Disadvantages
11. Cross Service Transactions Avoid, avoid, avoid If one part fails, how do you roll back everything? Use queues (RabbitMQ/SQS) and dispatch events
12. Eventual Consistency Data can’t be expected to be permanently consistent across services Read models may be updated from multiple sources
13. Service Discovery • Extremely frustrating • Services need to be load balanced • Can’t expose specific ports for a service
14. Denormalized data
15. Harder to test Might seem strange as earlier I mentioned they’re easier to test Unit tests are easier as you know the boundaries of each individual service and it’s collaborators Functional tests are nearly impossible
16. Reporting Push all data to one central store used ONLY for reporting • Redshift • Google BigQuery Do not use this data for transactional information Automatically updated views/queries for reporting
17. That Sounds Difficult!
18. CQRS To The Rescue • Have as many read models as your system requires • Build domain logic to handle commands/writes • Reads interact directly with the data-store • Use whatever data-store makes sense for the read model
19. How Does This Affect PHP?
20. Slim Lumen Silex
21. What About Development?
22. Problems... • Machines only have a certain amount of memory • Don’t want to checkout 50+ services to run 1 application
23. TIP Only run the services you need to
24. Being Selective • Only run the services you actually need to test • You’re only going to be add/updating 1 or 2 parts of the system, run those services
25. TIP Share your resources!
26. Shared Resources • Only do this for development… • No need to run 15 MySQL Containers/Instances on a local machine
27. TIP Provide an SDK to application teams
28. Application SDKs • Provide an SDK for every language / framework being employed to build an application • Expose your MicroService API via methods • Only need to update the SDK • Provide Mock data for development
29. Thanks For Having Me! Questions? @Luciam91 Slides http://speakerdeck.com/Luciam91