Ballerina is a modern programming language designed for integration, optimized for networked applications with strong typing and concurrency. It supports various data formats and APIs, offering a seamless experience for developers through its graphical and textual syntax. Open-source and extensible, Ballerina simplifies the creation and management of microservices and integration workflows.

1. Chintana Wilamuna
Solutions Architect
April, 06 2017
A programming language for the networked world
Asanka Abeysinghe
Vice President, Solutions Architecture
Future of Enterprise Integration Meetup: Silicon Valley

2. The world is changing …
• Networked interactions are no longer a niche
– The new shared library
– Ability to reuse and recompose is key to agility
– Everything you write integrates with other things
• Configuration over code not workable at scale
• Containers, microservices, micro integrations

3. Centralized vs decentralized
System
Ɣ
System
Ɣ
Service
Foo
Centralized Integration Solution
Service
Bar
System
α
System
β
Service
Foo
Integration
Microservice unit
Service
Bar
System
α
System
β
Integration Microservice unitVs

4. From data flows to sequence diagrams
• Every ESB technology based on dataflow
• Not very good at describing complex multi-party
interactions that are now common
• Sequence diagrams to the rescue
– Perfect for describing parallel, coordinated activities of many
parties

5. Timeline
2005
Apache Synapse
2008 Carbon
OSGified
Aug-2016 NEL
Q4-2016
Ballerina:
language spec
Apr-2017
0.85
Feb-2017
0.8 tec.preview

6. Why stop at using sequence diagrams to describe
programs?

8. Ballerina
• General purpose programming language, but optimized for
integration
• Strongly typed, concurrent with both text and graphical
syntaxes
• Modern, network-aware, data-aware, security-aware
programming system inspired by Java, Go, Maven, ...

9. The Ballerina Language
• Graphical/textual parity with ability to switch back and forth
• Common integration capabilities are baked into the language:
– Deep HTTP/REST/Swagger alignment
– Connectors for Web APIs and non-HTTP APIs
– Support for JSON, XML, (No)SQL data and mapping
• No magic – no weird syntax exceptions, everything is derived
from a few key language concepts
• Maximize developer productivity and abstraction clarity
• Support high performance implementations: low latency, low
memory and fast startup

10. Hello, World!
import ballerina.lang.system;
function main(string[] args) {
system:println("Hello, World!");
}

11. Demo: hello world

12. Ballerina knows services (and main)!
• Two models of programming: service and main
• Services are network invoked collections of entry points
• Main is regular main()

13. Demo: simple service

14. Ballerina knows data!
• XML, JSON and datatable are built-in data types
• All streamed, high performant
• Data (type) mapping between Ballerina types, XML, JSON and
datatables

15. Ballerina knows network APIs!
• Client and server connectors for HTTP 1.1/2, WebSockets, JMS,
(S)FTP(S) and more
• Client connectors for BasicAuth, OAuth, AmazonAuth, SOAP
• Client connectors for Web APIs: Twitter, GMail, LinkedIn,
Facebook, Lambda Functions, …

16. Ballerina knows (or rather, is) Swagger!
• Ballerina programs’ interface (in HTTP case) is
expressed in Swagger
– Text syntax, graphical syntax and Swagger syntax
are interchangeable
• Edit interface anywhere
• No more standard limitations of interface first design

17. Ballerina knows Docker!
• Built in build command to create Docker image with executable
Ballerina program package
• Run on any container management platform

18. Ballerina is highly extensible!
• Code organized into packages like Go
• Repository model similar to Maven/NPM/Go giving ability to
create ecosystem of connector contributors
• Recomposable network connectors

19. Ballerina is open source!
• Patent pending technology
• Implementation released under Apache License v2.0
– Fork me on GitHub: https://github.com/ballerinalang/
• Community
– Users: ballerina-user@googlegroups.com
– Slack: #ballerinalang
– Twitter: @ballerinalang
– StackOverflow: #ballerinalang
– Developers: ballerina-dev@googlegroups.com

20. Language Walk-Through
https://github.com/ballerinalang/ballerina/blob/master/docs/specification/README.
md

21. Ballerina Concepts
• Functions
• Services
• Resources
• Connectors
• Actions
• Workers

22. Modularity: Files & Packages
• Package model inspired by Go
– package org.wso2.foo;
• Packages are defined by the set of all files in a directory
• All symbols exposed by any file in the package is referred to with
packagename:symbolname
– In other words, file names have no meaning in the namespace of the language
• To use symbols from a package you must import:
– import org.wso2.foo [as xx];
• Packages that start with ballerina.* and ballerinax.* are reserved
• Packages will be versioned - details later

23. Type System
ANY
VALUE TYPE
INT
FLOAT
BOOLEAN
REFERENCE TYPE
BUILT-IN USER DEFINED
STRUCT ARRAY
STRING
MAP
EXCEPTION
MESSAGE
XML
JSON
ITERATOR
XMLDOCUMENT
DATATABLE

24. JSON Support
• Variables of type “json” can hold any JSON value
• Optionally, can associate a JSON Schema to the
declaration:
– json[<json_schema_name>] jsdoc;
– Constraints the value to conform to the schema
• Useful for type mapping
• JSON literals can be used to initialize JSON typed variables
– json address_json = `{"name" : "$name", "streetName" : "${street}"}`;

25. XML Support
• Variables of type “xml” can hold any XML element
• Variables of type “xmldocument” can hold any XML
document
• Optionally can associate an XML Schema to constrain the
value space of XML
– xml[<{xsd_namespace_name}type_name}>] e;
• XML literals
– xmlElement address_xml = `<address><name>${name}</name></address>`;

26. Tabular Data Support
• Variables of type “datatable” can hold any tabular data
coming from a data source
• Database connectors to query and produce datatables

27. Type Coercion and Conversion
• Lossless type coercions are automatic
– E.g. int -> float
• Other type conversions can be invoked with the cast
operator
– TypeT1 v1;
– TypeT2 v2;
– v2 = (TypeT2) v1;
• Users can define their own type mappers which fit into the
language type system and get invoked with the cast
operator

28. Type Mappers
typemapper TypeMapperName (TypeName VariableName) (TypeName) {
Statement;+
}
(More constraints coming)

29. Language Statements
• assignment
• if
• while
• break
• try/catch/throw
• return
• action invocation
• fork/join
• worker initiation/invocation/join/reply

30. Fork/Join
fork (MessageName) {
worker WorkerName (message VariableName) {
Statement;+
[reply MessageName;]
}+
} [join (JoinCondition) (message[] VariableName) {
Statement;*
} timeout (Expression) (message[] VariableName) {
Statement;*
}]

31. Fork/Join

32. Worker Interaction
worker WorkerName (message m) {
Statement;+
[reply MessageName;]
}
• Send/receive message to coordinate
MessageName -> WorkerName;
MessageName <- WorkerName;

33. Language System

34. Ballerina is not just the language
• Composer with debugging, type mapping
• IDE plugins
• Docerina
• Testerina
• (Coming soon) Packerina

35. Composer
• Textual, graphical and Swagger editing of Ballerina
programs
• Runs in the browser
– Currently not packaged with embedded Chromium;
considering it
• Will be hosted in the cloud as well

36. IDE Plugins
• Available (still WIP)
– Atom
– Vim
– Idea
– Sublime Text
– VSCode
– Adobe Brackets
• More to be done!
– Send a pull request ☺

37. Docerina
• Tool to generate API docs for your Ballerina code
• All Ballerina code is documented using Docerina

38. Testerina
• Unit test and mocking framework for Ballerina

39. Packerina
• Tool to manage repositories, manage dependencies and
build Ballerina programs
• Coming soon under this name .. partly shipping already

40. Ballerina Future

41. When should I use Ballerina?
• Write integration microservices
– 80-20 rule: if 80% of your service is about integrating with
other services, data and APIs then use Ballerina. If its just
20% then use Java / Node / Go / XYZ
• Re-compose existing services to be API backends
• Write integration scripts
– Replacement for shell scripts that use curl too much

42. Integration Microservice in MSA

43. Summary

44. Available now: Ballerina v0.85 Technology
Preview
• Language runtime
– Run once, run one service, run many services (bus)
• Developer tools
– Composer: browser based graphic/text/Swagger editor and
debugger
– IDE plugins: Idea, Atom, Vim, Sublime, VSCode, Brackets
– Testerina: Unit testing framework
– Docerina: API doc generation framework
• Connectors

45. http://ballerinalang.org/

46. Next Steps
• Download, twirl with it, give us feedback
• Engage with the community
– Users: ballerina-user@googlegroups.com
– Slack: #ballerinalang
– Twitter: @ballerinalang
– StackOverflow: #ballerinalang
– Developers: ballerina-dev@googlegroups.com

47. Demo: advanced use-cases

48. Questions?

49. Ballerina Concepts: Functions

50. Ballerina Concepts: Resource

51. Ballerina Concepts: Services

52. Ballerina Concepts: Client & Server Connectors
• Ballerina services are attached to network protocols with
server connectors
• Ballerina programs interact with network endpoints with
client connectors
– Networked endpoints can mean pretty much anything

53. WORKERCLIENT
CLIENT WORKER
CONNECTOR
CONNECTOR
CONNECTOR
CONNECTOR
START
REPLY
STATEMENT
ACTION
WORKER2
WORKER2