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This article focuses on "how to understand PayPal's application and development of Node.js". Interested friends may wish to have a look. The method introduced in this paper is simple, fast and practical. Let's let the editor take you to learn "how to understand PayPal's application and development of Node.js".

Historically, our engineering team's code has been divided into browser layers (using HTML, CSS, and JavaScript) and application layers (using Java). Imagine a HTML developer asking a Java developer to link "A" and "B" pages together, but that's who we are. The model lags behind those who can create a good user interface by introducing full-stack engineers, and then generate applications to support it. Call them unicorns, but that's what we want. In PayPal, the main blocker is the artificial boundary we establish between the browser and the server.

Node.js uses javascript to help us solve this problem by building browsers and server-side applications. It unifies our team and allows us to understand and respond to any needs of our users on the technology stack.

Early use of Node.js

Like others, we use Node.js as a prototype platform. Like everything else, it showed good performance and we decided to use it on the product.

In the beginning, we used express as the route, nconf as the configuration, and grunt to establish the workflow. We particularly like the popularity of the express framework, but find that it does not extend well across multiple development teams. Express is non-mandatory and allows you to set up a server in any way appropriate. It is very flexible, but it is not good for consistency in large teams. Over time, the patterns we see stand out, and more people pick up node.js and enter Kraken.js, which is not a framework itself, but a layer based on express, allowing it to extend to larger organizations. We want our engineers to focus on building their own applications, not just on building their own environment.

We have been using kraken.js internally for several months now (soon, we will open source), and our team of engineers is looking forward to turning it into a real-time internal node.js application.

Promote Node.js to the product

We first try node.js on the product is not a small application, it is our account overview page, this page has a lot of traffic. We're going to use it, but we also have to reduce the risk.

So we built a java application at the same time. We know how to deploy and measure java applications, so if anything goes wrong with the node.js program, we can quickly switch to java. It provides settings for some data.

Deployment

We started in January, and it took us months to study the necessary basics of node.js. Such as sessions, centralized logging, keystores. During this time, we have five engineers working with java. After 2 months of java development, two engineers began to use node.js to develop app in parallel. In early July, they communicated with each other, and their applications had the same functionality. The node.js app started with a smaller team 2 months later, but soon caught up. After a few details stand out, we run the test case, and the two applications pass the same functional test. Node.js is:

1) fewer people to build, almost twice as fast or even faster

2) 33% less code

3) create 40% or less files

This provides encouraging news that javascript can work faster. We all agreed and made a decision: put the java application on hold. But the problem is that java engineers are not confident in turning to node.js at the beginning of the project and are happy to submit code in our workflow to double our productivity.

Performance

Performance is a happy and controversial topic, and in our case, our team has two sets of applications with the same functionality: one using java based on Spring and the other based on kraken.js using express, dust.js and other open source code. This application contains three sets of routes, and each route has two or five requests, and the data is rendered through Dust.

In our test route, the data we collected was throughput and response time

You can see in our node.js application:

1) double the number of requests per second compared to Java applications. More interestingly, Node.js applications are single-core, while in Java there are five cores. We hope to further widen this gap.

2) 35% decline, the average response time is on the same page. As a result, users who respond to 200ms faster will surely notice.

For this result, I would like to make it clear that our framework uses two different applications, and it is only a peer-to-peer test on different technologies. It's possible that you have a bigger difference. In other words, we are very excited to see the performance of node.js.

Kraken: a Node.js Framework for changing PayPal Development Culture

PayPal (the world's popular online payment service) has released a Node.js Web development framework-Kraken.

Kraken based on Express,Express is the most popular Web development framework based on MVC pattern on Node.js. It helps developers to create various Web applications quickly by providing a series of powerful features. On the other hand, Kraken provides a more robust collection of functions on the basis of Express, supporting localization, environment configuration, paying more attention to application security and so on.

Why is there a Kraken?

In the past, PayPal had a long-standing culture of "not created by me", which led to a negative attitude towards PayPal's adoption of new technologies and extremely slow progress in project development. It is precisely because PayPal moves slowly, other payment service providers Stripe and Square take advantage of the opportunity to grow, gradually shaking the market position of PayPal. At the same time, the development technology of PayPal at that time has been unable to meet the needs of rapid development, because the development at that time is basically Java, and those that do not need to be implemented with Java will be completed with Java.

In April 2012, David Marcuss became president of PayPal and appointed a team of engineers to rewrite the payment system, which generated $3.5 billion in revenue for PayPal, within six weeks. In the end, the team of engineers took eight weeks to complete the task, and they chose Node.js to redevelop the system. Of course, a large number of other subsystems of PayPal need to be integrated into the Node.js system, so at first Node.js was only used as a rapid development prototype architecture.

Later, more and more new development projects of PayPal are gradually completed by Node.js and other open source software, which led to the birth of a Kraken.js project that can quickly develop Web applications.

Below, we briefly summarize and analyze the framework structure and characteristics of Kraken, hoping to help you understand Kraken better.

Kraken Framework Kit

The Kraken framework suite consists of several parts, and Kraken.js is only the main part of the framework. The framework also includes other modules (which can be used independently):

Lusca: an application security module that supports Express

Makara: internationalization (i18n) module that supports Dust.js

Adaro: a Dust.js view renderer that supports Express

Kappa:NPM proxy plug-in

In addition to the above stand-alone modules, the Kraken suite includes a series of dependencies and utilities:

Generator-kraken:Yeoman generator

Enrouten: routing (route) configuration middleware for Express (initialization and configuration module)

A collection of tools needed for Kraken-devtools:Kraken application development

Characteristics of Kraken

Through the previous introduction, we have a basic understanding of what Kraken is all about, so what are the features of Kraken that attract developers?

1. The project structure is clear

Kraken puts the configuration, content and templates, and routing logic (routing logic) of the generated project in different locations, making it easy for developers to organize and manage files. Let's take a closer look at the basic structure of the project created by Kraken:

/ config to store the application and middleware configuration

/ controllers, controller

/ lib, which stores developer-defined library files and other code

/ locales, specific language content

/ models, model

/ public, a public network resource

/ public/templates, server and browser-side templates

/ test, storing units and functional test cases, etc.

Index.js, application entry file

As the project grows, this organization and strategy will be more friendly to developers.

two。 A good balance between development environment and production environment

The configuration file for Kraken is / config/app.json, which loads the key-value pairs contained in the file at run time. All the application configurations are stored in this file, which is very convenient for developers. / config/middleware.json is a custom middleware configuration file.

When it comes to the development environment and the production environment, the two usually have different parameter settings in terms of port number and host name. Kraken allows you to create configuration files for use in the development mode, such as / config/app.json for the production environment and / config/app-development.json for the development environment. You can then control which configuration file is loaded by customizing the environment variable (defining the environment variable NODE_ENV to production or development). In this way, it is convenient for developers to quickly switch between production environment and development environment.

3. Pay attention to safety

Escort security through the Lusca module, and follow the OWASP security principles, and also default to enable several request / response header files for all calls:

Cross-site request forgery (CSRF) header

Content Security Policy (CPS) header

Privacy priority platform (P3P) header

X-FRAME-OPTIONS prevents click hijacking

4. Other

Meanwhile, it also has the following features:

Separation of route and logic: facilitates a quick locking problem when a program fails.

Template sharing: Kraken uses Dust as the template language and uses the same template on both the server side and the client side, so that code can be reused.

Support localization: Kraken can load content packs (content bundle) based on the request context at run time, so you can provide users with local language support by adding context before the template rendering, greatly enhancing the application friendliness.

Examples and documentation

With regard to Kraken, officials have given the following two examples to help you learn and understand:

Example 1: localization and internationalization: add multilingual support to Web applications, so that users everywhere can use Web applications in local languages

Example 2: deploy middleware: create a web counter to explain how to deploy middleware during the application lifecycle

Open source project

Kraken is an open source project (the distribution protocol is Apache License v2.0), and everyone can Fork and submit changes to the project. It also provides a concise usage document. The project source code and documentation can be viewed on the Github page.

Last

The birth of any project has its background, and there must be a corresponding demand-driven. Just like Kraken, it is precisely because PayPal chose Node.js to meet its strong demand for the rapid development of Web applications that led to this project.

At the same time, we also need to pay attention to the "non-self-created" culture in the engineer team, and adopt a positive attitude towards the new technology, otherwise it will hinder the development of the enterprise.

At this point, I believe you have a deeper understanding of "how to understand PayPal's application and development of Node.js". You might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

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