This code checks if Docker is installed by running the docker ps command and signals completion with a message indicating whether Docker is found or not.

Run example

npm run import -- "install Docker on Windows"

install Docker on Windows

$.async();
var exec = require('child_process').exec;
var installed = false;
var docker = exec('docker ps', function (err, stdout, stderr) {
    if (stdout.indexOf('not found') > -1) {
        $.done('Docker not found, installing');
    } else {
        installed = true;
        $.done('Docker is already installed');
    }
});

// Import required modules
const childProcess = require('child_process');
const { async: $, done } = require('./asyncUtil'); // Assuming asyncUtil is a separate module

// Define a constant for docker command
const DOCKER_PS_CMD = 'docker ps';

// Define a function to check if docker is installed
const checkDockerInstalled = async () => {
  try {
    // Execute docker ps command
    const { stdout } = await childProcess.exec(DOCKER_PS_CMD);
    if (stdout.includes('not found')) {
      // Docker not found, install it
      await $;
      return 'Docker not found, installing';
    }
    // Docker is already installed
    return 'Docker is already installed';
  } catch (error) {
    // If command execution fails, return an error message
    return `Error executing command: ${error.message}`;
  }
};

// Call the function to check docker installation
checkDockerInstalled()
 .then((message) => done(message))
 .catch((error) => done(`Error checking docker installation: ${error.message}`));

This code snippet checks if Docker is installed on the system and signals completion based on the result.

Breakdown:

1. $.async();:

   • This line likely initializes an asynchronous operation using a variable $ (possibly a custom function or library).

2. var exec = require('child_process').exec;:

   • Imports the exec function from the child_process module, which allows executing shell commands.

3. var installed = false;:

   • Initializes a boolean variable installed to false, assuming Docker is not installed initially.

4. var docker = exec('docker ps', function (err, stdout, stderr) { ... });:

   • Executes the command docker ps (which lists running Docker containers) using exec().
   • The callback function handles the result:
     • err: Error object if any occurred during execution.
     • stdout: Standard output from the command (the list of containers).
     • stderr: Standard error output (if any).

5. Inside the callback:

   • if (stdout.indexOf('not found') > -1) { ... }:
     • Checks if the output contains the string "not found", indicating Docker is not installed.
     • If found, calls $.done('Docker not found, installing') to signal the asynchronous operation with a message.
   • else { ... }:
     • If "not found" is not found, it means Docker is installed.
     • Sets installed to true.
     • Calls $.done('Docker is already installed') to signal completion with a success message.