List of executables available in Firebase Cloud Functions Node.js runtime

google-firebase-functions-list-available-executables.js

/**
 * List of executables in Cloud Functions runtime.
 * Invoke with https://us-central1-‹project-name›.cloudfunctions.net/ls
 */
const functions = require( "firebase-functions");
const spawn = require( "child-process-promise").spawn;

const ls = (req, res) => {
  console.log( "Listing contents of /usr/[local/][s]bin");
  return spawn( "ls",
      [ "-1F", "/usr/local/bin", "/usr/local/sbin", "/usr/bin", "/usr/sbin" ],
      { capture: [ "stdout", "stderr"] })
    .then(( result) => {
      console.log( "List of files", result.stdout);
      return res.status( 200)
                .send( `List of files: ${result.stdout.split("\n").join("<br/>")}`);
    })
    .catch(( err) => {
      console.error( `ls error: ${err.stderr}`)
      throw err;
    });
};

exports.ls = functions.https.onRequest( ls);

Nice, next to ImageMagick and many utilities to work with the PBM image format, Ghostscript is also available on the command-line to process PDF and PS documents. Although not explicitely listed in Google Cloud Node.js runtime image, it probably comes from the base Ubuntu 16.04 image.