[wso2con eu 2017] introduction to ballerina

Senior Director - Platform Architecture, WSO2

Introduction to Ballerina

Afkham Azeez

http://ballerinalang.org

• An event-driven, parallel programming language for networked applications

• Textual and graphical syntaxes with sequence diagram metaphor

• Strongly and statically typed with powerful type system• Designed for network with JSON, XML, SQL, MIME and

HTTP, WebSocket, MQTT, etc.• Modular and designed for modern development practices• Microservices, serverless, and container friendly

Ballerina

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.

Yet Another Programming Language?

• Type system mismatches – no understanding of JSON, XML, SQL

• Generally poor at handling asynchronous programming• Writing network resilient programs is hard/error-prone• DSLs for integration (Camel/ESBs) are not workable at

scale• Heavy – unsuitable for microservices, serverless,

containerized world

Motivation for Ballerina

function main (string[] args) { println("Hello, World!");}

Hello World

$ ballerina run hello-world.bal Hello, World!

Running

Ballerina Knows JSON, XML, and data

• All a 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

• JSON is a union type– Can be an object, an array, or a simple

value (string, number, boolean)

• Literal value syntax same as other record types

JSON

json j = {fname:"John", lname:"Stallone", "age":age};

• New tree-less data model• Deeply merged to language

– Embedded literal syntax– XML qualified names and Ballerina qualified

names unified

XML

function main (string[] args) { xml person1 = xml `<person><fname>John</fname><lname>Doe</lname></person>`; xml person2 = xml `<person><fname>Jane</fname><lname>Doe</lname></person>`;

xml persons = xml `<persons/>`;

persons.setChildren(persons, person1 + person2); println(persons);}

Example

• Represents tabular data– SQL– Cassandra– MongoDB– etc

• SQL connector is transaction-aware and produces streaming datatables that can efficiently move data from database to network

Datatable

endpoint<sql:ClientConnector> empDB { create sql:ClientConnector(sql:MYSQL, "localhost", 3306, "empdb", "root", "root", {maximumPoolSize:5});}

datatable dt = empDB.select("SELECT id,name from employees", params);

var j, _ = <json>dt;println(j);

Example

Ballerina Knows Network Protocols

• HTTP, WebSocket, JMS, FTP, Files, etc. • Popular APIs: Facebook, Twitter, Gmail,

LinkedIn, etc.• Extensible authentication/policy support

import ballerina.net.http;

service<http> helloWorld { resource sayHello (http:request req, http:response resp) { resp.setStringPayload ("Hello, World!"); resp.sendResponse (200, "OK"); }}

Ballerina Services

$ curl http://localhost:8080/helloWorld

Hello, World!

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

ballerina swagger connector http://petstore.swagger.io/v2/swagger.json -d swagger-example/petstore/ -p org.example

Ballerina is Naturally Parallel

• Sequence diagram approach makes parallelism innate

• Think parallel first, not sequential first

function main (string[] args) { worker w1 { println ("Hello, World from w1!"); } worker w2 { println ("Hello, World from w2!"); } worker w3 { println ("Hello, World from w3!"); }}

Parallel Hello World

$ ballerina run hello-world-parallel.bal Hello, World from w1!Hello, World from w2!Hello, World from w3!

Running

Ballerina Supports Safety & Resiliency

• Highly structured error and exception handling• Taint checking of network delivered data• Built-in retrying, failover, load balancing, and

more, to make programs more resilient to network failures

transaction [with acid, retry(expression)] { statement;*} [failed { statement;*}] [aborted { statement;*}] [committed { statement;*}]

Ballerina Transactions

• A common requirement in integration• Different systems have different data formats

Data Transformation

Example

transformer <Person p, User u> { u.username = p.first_name; u.category, u.ageCode = getCategory(p.age); u.geoCode = getGeoCode(p.state, p.city); u.name = p.first_name;}

Person p = {first_name: "John", last_name: "Doe", age: 30, city: "London"};User u = <User> p;

Example

IO API

• Endpoints are logical entities that represent remote services

• Connectors are like the type (class): for example an HTTPClient connector

• Connections are instances– e.g. the connector configured with a particular URL

and credentials• Actions are invoked on connections

Endpoints, Connectors, Connections & Actions

Ballerina Knows Docker

• Built in ability to create Docker image with executable Ballerina program package

• Run on any container management platform

ballerina docker hello-world.balx

Ballerina is Open Source

• Patent pending technology• Implementation released under Apache License v2.0

– Fork me on GitHub: https://github.com/ballerinalang/• Community

– Slack: #ballerinalang– Twitter: @ballerinalang– StackOverflow: #ballerinalang– Developers: ballerina-dev@googlegroups.com

• Graphical composer in browser/as IDE• IDE plugins - Intellij IDEA, Visual Code, Atom, Eclipse,

etc.• Testerina - testing and mocking tool• Docerina - API doc generation tool• Packerina - library and package management tool

Ballerina is More Than a Language

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