Intro to Node.js (German)

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Netflix, Tinder, NASA – Node.js und die Digitale TransformationDaniel KhanNode.js Technology Lead

Daniel Khan• @dkhan• [email protected]• Node.js Technology Lead

www.dynatrace.com

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Gegründet in Linz 2006210 Mitarbeiter in LinzWeltweit ca. 2.000#2 Arbeitgeber Ranking

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Complete Transaction CoverageBrowser / Native Mobile Java/

.NET

PerformanceWarehouse

PurePathCollector

DynatraceServer

DynatraceClient

SessionsStore

ExportedSession

OfflineSession Analysis

Web Server/ PHP

C++, VB, ADK

CICS

Mainframez/OS

MQ/ESB

Database

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@dkhanQuelle: Indeed Job Trends

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Relativ!

Quelle: Indeed Job Trends

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Node@Dynatrace | März 2015

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Bestehende KundenNicht unbedingt Startups

Node Foundation

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“Digital Transformation”

We see ourselves as a technology company with a banking license

“”Michael Corbat

PDG de Citi

Nike has many more software developers in Oregon than

apparel designers.*

“”*from Dynatrace Perform 2015

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November 2016“Wir sehen Node.js überall in den USA’

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Quelle: IBM/StrongLoop

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Node.js komplementiert bestehende Systeme

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Aber warum ausgerechnet Node.js?

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JavaScript• Easy to learn / easy to find developers• No language boundaries between frontend and backend• Easy to deploy and rollback• Fast development cycles

PayPal built a web app side by side in Node and Javaand the Node version was:• Built almost twice as fast with fewer people• Written in 33% fewer lines of code• Constructed with 40% fewer files

Source: https://www.paypal-engineering.com/2013/11/22/node-js-at-paypal/

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Performance• Google V8 JavaScript Engine• Non-Blocking I/O• Asynchronous event based execution

Node.js shines in modern web-connected applications where it needs togather data from different sources, consolidate it and push it to manyclients in real-time.

Never(!) use it for CPU-bound tasks!

Source: PayPal

Double the requests per second vs. the Java application.

35% decrease in the average response time

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Usecases

• Authentifizierung / Autorisierung• Proxy / Vermittler• Datentransformation• Präsentation (HTML)

Node.js in a Nutshell

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Node Standard Library

Node Bindings

V8 Thread Pool

Event Loop

JavaScript

C++

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“Asynchronous I/O"

DatabaseBrowser Java Application

1 Thread per request

If number of max threads is exhausted requests are

blocked

Threads are waiting, doing nothing

Thread context switches, synchronization necessary

Traditional approach

DatabaseBrowser Node.js Application

IO Threads

Event-handling in 1 Thread

Reduced waiting time

More concurrent requests possible

No synchronization necessary

Nodes approach

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“Node.js ist Single Threaded”

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calculateFibonacci();

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Die Event Loop

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Erste Schritte zu einer Node.js Applikation

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Über 350.000 Module auf npm

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• JavaScript ist einfach• Dynamisch typisiert• Einfache API für

asynchrone Tasks• Erstklassige I/O

Performance• Einfaches Deployment

• JavaScript ist einfach• Dynamisch typisiert• Nicht geeignet für CPU-

Aufwändige Aufgaben• Events und Callbacks führen zu

komplizierten Strukturen (Callback Hell)

Contra:Pro:

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If all you have is a hammer, everything looks like a nail

Abraham Maslow, 1966

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Thank You! | Daniel Khan | @dkhan | [email protected]