Kasun Indrasiri discussed the evolution of application architectures from monolithic to microservices and the need for integration between microservices. He described how Netflix, Uber, and PayPal implement service compositions in their microservice architectures. He then introduced the concept of integration or composite microservices that are used to integrate APIs, legacy systems, databases, and other microservices. Ballerina was presented as an open source framework for building these types of integration microservices with features like graphical definitions and network abstractions. Service meshes were also briefly mentioned as tools for managing inter-service communications at scale.

1. Bridging Microservices, APIs and Integration
Microservices and Cloud Native Apps - SF Bay Area
Cloud Field Day Edition, Santa Clara
July 2017
Kasun Indrasiri
Director-Integration Architecture at WSO2

2. About Me
● Director - Integration Architecture at WSO2
● Committer/PMC Apache Synapse, an architect of WSO2 ESB
● Author ‘Beginning WSO2 ESB’, several microservices articles/white papers
WSO2
● Open source middleware company
● API Management, Integration, IAM and IOT platforms.

3. Evolution of Microservices
Monolithic Applications

4. Evolution of Microservices
SOA

5. Evolution of Microservices
SOA with APIs

6. Evolution of Microservices
Microservices

7. Why Microservices Compositions?
● Too many fine-grained microservices.
● Business functionalities often require to interact with more than one
(micro)service.
● Microservices typically don't publish their APIs for direct invocation.
● Brown-field reality requires ‘Integration’
○ Green fields enterprises don’t exists.
○ Hybrid usage of Microservices and monolithic architecture is quite common.
○ Need to integrate with existing legacy systems, proprietary systems, databases
and SaaS.

8. Glimpse of existing Microservice Implementations
● How do the existing microservice implementations handle the service
compositions/service orchestration?

9. Microservice - Compositions
Netflix
● The Netflix API is the “front door” to the
Netflix ecosystem of microservices.
● API provides the logic of composing calls to
all services that are required to construct a
response.
● The Netflix API is an orchestration service
that exposes coarse grained APIs by
composing fined grained functionality
provided by the microservices.
● Orchestration logic is built with Java, RxJava

10. Microservice - Compositions
Uber
● ‘Edge Services’ which are exposed to the
external client/mobile applications and the
service orchestration logic is burnt into the
edge service.
● Edge services are primarily implemented
on top of Node.js

11. Microservice - Compositions
Paypal
● The API façade layer exposes Paypal
business functionalities to various internal
and external client applications
● The orchestration logic resides in the API
façade layer and its implemented using
Groovy.

12. Miniservices
“A miniservice is a coarse-grained, independently deployable and independently
scalable application component.”
● “Innovation Insight for Miniservices” : Published: February 2017
○ https://www.gartner.com/doc/3615120/innovation-insight-miniservices

13. The ‘new’ monolith…
API Gateway
● A central gateway with heavy composition
logic is becoming an anti-pattern.
● https://medium.com/netflix-techblog/engineering-trade-offs-and-
the-netflix-api-re-architecture-64f122b277dd
● Ability to develop, deploy and scale APIs
independently -> Micro-API Gateways

14. Pragmatic Microservices Architecture
● Microservices types with different granularities

15. Integration/Composite Microservices
● A composite microservice with multiple network interactions
● Create composite microservices by integrating web APIs/SaaS, legacy
systems and microservices
● API services/Edge service is also an integration microservice with some API
gateway capabilities.
● Similar to the ‘Miniservice’ concept wrt to the granularity

16. Technologies for building Composite/Integration
Microservices
● Frameworks based on general purpose lang. : Java, Node.js, Groovy - e.g.:
SpringBoot, Dropwizard
○ Not designed with suitable abstractions for integration/network interactions
○ Compositions cannot be illustrated graphically.
● Apache Camel and other ESBs.
○ Bulky traditional ESB architecture -> Not fully compatible with MSA principles.
○ High level DSLs with a lot of tweaks to make it a powerful programming lang. (e.g. expression
languages, properties)
● Ballerina - ballerinalang.org - Open source microservice composition
framework
● Service mesh frameworks - for Inter-service communication

17. Ballerina (ballerinalang.org)
● Ballerina is a new parallel programming language that is designed and
optimized for integration.
● Graphical and textual syntax which is built on top of the sequence diagram
metaphor.
● Designed for network interactions with JSON/XML/SQL/MIME and
HTTP/JMS/File/WebSockets
● Lightweight, high-performance and container native Integration runtime
● 100% open source.

18. Routing Service

19. Ballerina - Key Concepts
Components Overview

20. Ballerina - Features
● Network Protocols
○ HTTP/HTTP2, WebSockets, JMS, File/FTP, Databases
○ SaaS Integration - Salesforce, Twitter, Gmail, etc.
○ Proprietary and legacy connectors
● Service definition and implementation
○ Swagger, Jax-RS like service annotations
● Data Types
○ Native support for JSON, XML and SQL data
○ Graphical Type mapping
● High performance and container native
○ One of the fastest HTTP transport based on Netty
○ Minimal Startup time(< 1s), low resource consumption.
○ Built-in ability to create Docker image with executable Ballerina program package
○ Run on any container management platform

21. Ballerina - Future
● Ballerina 1.0 release on 2017 Q4
● Why yet another language?
○ Make it easier to consume and produce networked services and applications.
○ Ballerina has been influenced by Java, Go, C, Node, Javascript, Maven, Tomcat, and a variety
of other awesome tools.
● When should I use Ballerina?
○ Write integration microservices/miniservices: 80-20 rule
■ If 80% of your service is about integrating with other services, data and APIs then use
Ballerina.
■ If just 20% is integration then use Java / Node / Go / PHP / XYZ
○ Re-compose existing services to be API backends
○ Write integration scripts
■ Replacement for shell scripts that use curl a lot

22. When to use Ballerina?

23. Ballerina - Try it!
● DOWNLOAD v0.91 and twirl away:
○ http://ballerinalang.org/
● Source Code : https://github.com/ballerinalang/
● NOTE: Still work-in-progress. New releases every two weeks with major
features still coming along. Missing docs. A (few) bugs. Etc.!

24. ● Managing a network of microservices and inter-service communications
● Not really a composite microservice development technology.
● Eg: Istio - https://istio.io, Linkered https://linkerd.io/
Service Mesh Solutions

25. ● Understanding service granularities.
● Technologies for building integration microservices.
Summary

26. Thank You!
● kasun@wso2.com
● https://twitter.com/kasunindrasiri