- Integration microservices are used to compose other microservices and APIs to create new services, similar to the concept of "miniservices". They help integrate web APIs, legacy systems, and microservices. - Technologies for building integration microservices include frameworks like SpringBoot and Dropwizard, Apache Camel, and the Ballerina programming language. Ballerina is designed specifically for integration and allows graphical composition of services and connectors. - Integration microservices are an important part of microservices architecture as they handle service compositions and orchestration between multiple microservices and external APIs.

1. Integration Microservices
Bridging Microservices, Integration, and APIs
SF Microservices - June Meetup 2017
Kasun Indrasiri
Director-Integration Architecture at WSO2

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

3. Microservices Architecture in a nutshell
Monolithic Applications

4. Microservices Architecture in a nutshell
SOA

5. Microservices Architecture in a nutshell
SOA with APIs

6. Microservices Architecture in a nutshell
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. Microservices and ESB - Facts and Myths
● How to Integrate Microservices/How to create microservice compositions?
● From ESB to ‘Smart endpoints and dumb pipes’
○ Routing logic or business logic that resides at the central ESB layer has to be segregated and
distributed among the (smart) clients and (micro) services.
(source : YOW! 2016 — Microservices by Martin Fowler)

9. Microservices and ESB - Myths and Facts
Point to Point Interactions
● Strict, dogmatic adherence to ‘smart-endpoint and dumb pipes’ results
Point-to-point(P2P) connectivity between your services and consumers.
● P2P approach is not scalable and exponentially increases the complexity of
the service interactions.
‘Smart-endpoint and dumb pipes’ in practice (source : Microservices in Practice)

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

11. 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

12. 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

13. 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.

14. Miniservices
“A miniservice is a coarse-grained, independently deployable and independently
scalable application component.”
● “Innovation Insight for Miniservices” : Published: 21 February 2017
○ https://www.gartner.com/doc/3615120/innovation-insight-miniservices

15. Pragmatic Microservices Architecture
● Microservices types with different granularities

16. Integration Microservices
● Composing microservices and create a new service
● Similar to the ‘Miniservice’ concept wrt to the granularity
● Integrate web APIs/SaaS, legacy systems and microservices
● API services/Edge service is also an integration microservice with some API
gateway capabilities.

17. Technologies for building 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.

18. 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.

19. Hello World - Service

20. Hello World - Main

21. Ballerina - Key Concepts
Components Overview

22. Ballerina - Key Concepts
Service and Resource
● A service comprises of a homogeneous collection of network accessible entry
points; ‘resources’.
● A ‘resource’ contains the set of statements which are executed sequentially.

23. Ballerina - Key Concepts
Workers
● Worker is a thread of execution that can be programmed independently.
● A resource or a function contains the default worker that where you
sequentially configure the ballerina programming logic.

24. Ballerina - Key Concepts
Server Connectors
● Services are protocol agnostic.
● You can bind a ‘Server Connector’ to any service to receive messages from
respective the network protocol.
● Are defined as platform extensions – not written in Ballerina
● May offer of utility functions to access info in the message
● Can be configured via annotations that bind a service to a server connector.

25. Ballerina - Key Concepts
Connectors and Actions
● Ballerina is all about integrating with other systems using connectors
● “Other systems” are represented by a (client) “connector” that defines a set of
“actions” that you can do with that system
● The client connectors represent an external system that is accessible through
the network such as HTTP service, Database or any SaaS application.
● Graphically, the connector is represented as an actor in the sequence diagram
(i.e. a vertical line) and actions are boxes that go into a worker with lines going
to the actor.

26. Ballerina - Key Concepts
Functions
● Represent the reusable integration scenarios/code.

27. Ballerina Demo
Code is located at :
https://github.com/kasun04/rnd/tree/master/ballerina_use_cases

28. Ballerina knows main() and services
● Run as a command line program
● Run as a network service.

29. Ballerina knows JSON, XML and SQL data
● All part of Ballerina type system
● Deeply unified and integrated both syntactically and semantically
● Data transformation across all of these graphically and textually
● Transactional data management

30. Ballerina knows network protocols
● HTTP, WebSockets, JMS, FTP, Files, ...
● Popular APIs: Facebook, Twitter, Gmail, LinkedIn, …
● Extensible authentication / policy support

31. Ballerina knows Swagger
● Ballerina services’ interface is Swagger and Ballerina syntax, Swagger YAML
syntax and graphical syntaxes are interchangeable
● Reduces pains of interface-first design

32. Ballerina is naturally parallel
● Sequence diagram approach makes parallelism innate
● Think parallel first, not sequential first

33. Ballerina supports safety & resiliency
● Highly structured error and exception handling
● Taint tracking of network delivered data
● Stability Patterns : Supports Timeout, Circuit Breaker
● Failover, Load balancing, Reliable delivery.

34. High Performance and Container-native runtime
● Performance
○ Extremely lightweight and high performant runtime.
○ Minimal Startup time(< 1s), low resource consumption.
● Container-native
○ Built in ability to create Docker image with executable Ballerina program package
○ Run on any container management platform

35. Ballerina is Open Source!
● Implementation released under Apache License v2.0
○ Fork me on GitHub: https://github.com/ballerinalang/
● Community
○ Developers: ballerina-dev@googlegroups.com
○ Slack: #ballerinalang
○ Twitter: @ballerinalang
○ StackOverflow: #ballerinalang

36. Ballerina - Future
● 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

37. Ballerina - Try it!
● DOWNLOAD v0.87 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.!

38. ● Integration Microservices plays a key part of MSA.
● Understanding service granularities.
● Technologies for building integration microservices.
Summary

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