Learn how to use Puppeteer in function calculations in 3 minutes

Introduction to the

Using Puppeteer combined with function computing, you can quickly build resilient services to perform a variety of functions, including:

• Generate web screenshots or PDFS
• Advanced crawler, can climb a large number of asynchronously rendered content of the web page
• Simulate keyboard input, form automatic submission, login web page, etc., to achieve UI automatic testing
• Capture a timeline of your site to track your site and help analyze site performance issues

Next, we will develop our own Puppeteer project based on a scaffolding project.

Download the project

>>> git clone -o starter-kit https://github.com/awesome-fc/puppeteer-fc-starter-kit.git your_project_nameCopy the code

The project structure

├─ chrome │ ├─ buildchrome. sh buildChrome headless shell script based on the ├─ chrome │ ├─ buildchrome. sh buildChrome headless shell script based on the ├─ chrome │ ├─ buildChrome. You can compile the latest version │ └ ─ ─ headless_shell. Tar. Gz compiled chrome headless binary package files ├ ─ ─ the SRC │ ├ ─ ─ index. The js function call entry documents, │ ├─ gene-starter -kit │ ├─ config.js └─ gene-starter -kit │ ├─ config.js └─ gene-starter │ ├─ local.js To check whether the Chrome Headless API is correct by running NPM runlocal├─ ├─ package.zip, └─ ├─ package.zip, └─ ├─ garbage, └─ garbage, └─ garbage, └─ garbage, └─ garbage NPM run package or NPM run package-nochromeCopy the code

How to write business code

Index. Js file

const setup = require('./starter-kit/setup'); exports.handler = async (event, context, callback) => { const browser = await setup.getBrowser(context); exports.run(browser).then( (result) => callback(null, result) ).catch( (err) => callback(err) ); }; Exports.run = async (browser) => {// Implement your own business code // here is a sample code, Const page = await browser.newPage(); const page = await browser.newPage(); await page.goto('https://fc.console.aliyun.com');
  return page.screenshot({
    clip: {
      x: 200,
      y: 60,
      width: 780,
      height: 450,
    },
  });
};Copy the code

Local test

Run NPM run local. Test that your API for operating Chrome Headless works correctly.

Compile the package

Contains chrome headless

Run the NPM run package command. The command will pack chrome Headless files into the project and place them in the root directory of the project. When this function is executed, chrome Headless will be installed in/TMP by default.

Chrome Headless is not included

Run NPM run package-nochrome. The chrome Headless command will not package chrome headless files into the project, you will need to upload Chrome-headless files to OSS in addition, and use environment variables to tell functions how to download and install from OSS. By default, Chrome Headless will be installed in/TMP directory. Set environment variables for function evaluation:

• CHROME_BUCKET(Mandatory): Chrome headless bucket uploaded to the OSS
• CHROME_REGION(Mandatory): Chrome headless region uploaded to OSS
• CHROME_KEY(Mandatory): Chrome headless key to upload to OSS. Default value: headless_shell.tar.gz

The deployment of

Compile the packaged output file: package.zip, and upload the packaged file using the function computing console or the fCLI command tool. Fcli Command for uploading packaged files:

# in the corresponding service directory
>>> mkf myFunction -h index.handler -f package.zip -t nodejs8 The code is in package.zipCopy the code

Why use a function

Functional computing is a relatively new thing, probably unfamiliar to most developers or architects. Microservice architecture is a very popular system architecture at present. Is there anything not perfect about microservice architecture? The answer is yes. Based on the microservice architecture, we need to consider what microservice framework to use to construct the system, how many servers are needed, and how to effectively reduce the burden of operation and maintenance. In addition, according to Forbes magazine, typical servers in commercial and enterprise data centers provide only 5 to 15 percent of their average maximum processing power output. This is undoubtedly a huge waste of resources.

Is there a way to solve the above shortcomings? The answer is also yes, Ali cloud function calculation is in this context emerged. If the cloud computing as an execution environment, so, in this environment, the function (i.e., the carrier of the business logic) + data (i.e., input and output related to business) is the core of the application, function, data, events, these three any other code and framework, is nothing but the application of glue and the UI. The ideal scenario, then, is to spend as little time writing glue as possible, devote more time to core application development, and even microservize the entire software stack. The function calculation is the glue here.

Development efficiency

reliability

The cost of

security

conclusion

Function calculation has the following advantages:

• No need to purchase and manage infrastructure such as servers
• Focus on business logic development
• Provides log query, performance monitoring, and alarm functions to quickly rectify faults
• Trigger an application to respond to a user request in an event-driven manner
• Flexible expansion at the millisecond level enables rapid expansion of the bottom layer to cope with peak pressure
• Pay on demand. You only need to pay for the computing resources actually used, which is suitable for user access scenarios with obvious peaks and troughs
• The original link