index.js

var path = require('path')
var tar = require('tar-fs')
var fs = require('fs')

/**
 * Installs git binaries and updates this process's PATH to include
 * them, so you can child_process.exec('git') successfully.
 *
 * Git bundle is extracted to the the target directory. This defaults to
 * /tmp/git, but can be set with the `targetDirectory` option.
 *
 * The current process's path is prefixed with the binary folder, and other
 * required env vars for Git are set. If you set `updateEnv` to false in
 * your options then no changes will be made an object will be returned
 * instead including `binPath` (the path to the binaries folder) and `env`,
 * a set of required environmental variables.
 */
module.exports = function installGit(options) {
  return new Promise((resolve) => {
    options = options || {}

    var targetDirectory = options.targetDirectory || '/tmp/git'
    var updateEnv = (options.updateEnv !== undefined) ? options.updateEnv : true

    var reader = fs.createReadStream(path.join(__dirname, 'git-2.4.3.tar'))
    reader.pipe(tar.extract(targetDirectory))
    reader.on('end', done)

    var GIT_TEMPLATE_DIR = path.join(targetDirectory, 'usr/share/git-core/templates')
    var GIT_EXEC_PATH = path.join(targetDirectory, 'usr/libexec/git-core')
    var LD_LIBRARY_PATH = path.join(targetDirectory, 'usr/lib64')
    var binPath = path.join(targetDirectory, 'usr/bin')

    function done() {
      if (updateEnv) {
        process.env.PATH = process.env.PATH + ":" + binPath
        process.env.GIT_TEMPLATE_DIR = GIT_TEMPLATE_DIR
        process.env.GIT_EXEC_PATH = GIT_EXEC_PATH
        process.env.LD_LIBRARY_PATH = process.env.LD_LIBRARY_PATH
          ? process.env.LD_LIBRARY_PATH + ":" + LD_LIBRARY_PATH
          : LD_LIBRARY_PATH
        resolve()
      } else {
        resolve({
          binPath: binPath,
          env: {
            GIT_TEMPLATE_DIR: GIT_TEMPLATE_DIR,
            GIT_EXEC_PATH: GIT_EXEC_PATH,
            LD_LIBRARY_PATH: LD_LIBRARY_PATH
          }
        })
      }
    }
  })
}