Spawn binary from AWS Lambda

example.js

var fs = require('fs');
var Q = require('q');
var spawn = require('child_process').spawn;
var path = require('path');

// Make sure you append the path with the lambda deployment path, so you can 
// execute your own binaries in, say, bin/
process.env["PATH"] = process.env["PATH"] + ":" + process.env["LAMBDA_TASK_ROOT"] + '/bin/';

function spawnCmd(cmd, args, opts) {
  var opts = opts||{};
  var basename = path.basename(cmd);

  console.log("[spawn]", cmd, args.join(' '), opts);

  var deferred = Q.defer();
  child = spawn(cmd, args, opts);
  child.stdout.on('data', function(chunk) {
    console.log("[" + basename + ":stdout] " + chunk);
  });

  child.stderr.on('data', function(chunk) {
    console.log("[" + basename + ":stderr] " + chunk);
  });
  child.on('error', function (error) {
    console.log("[" + basename + "] unhandled error:",error);
    deferred.reject(new Error(error));
  });
  child.on('close', function (code, signal) {
    if(signal) {
      deferred.reject("Process killed with signal " + signal);
    } else if(code==0) {
      deferred.resolve(code);
    } else {
      deferred.reject("Process exited with code " + code);
    }
    console.log("[" + basename + "] child process exited with code",code, "signal", signal);
  });

  return deferred.promise;
}

exports.handler = function(event, context) {
  spawnCmd("/usr/bin/uname", ["-a"], {
      cwd: '/tmp'
  }).then(function(result) {
    context.succeed(result);
  }, function(err) {
    context.fail(err);
  });
}

Thanks for this, it was really helpful to me!

I ended up changing it a bit to use child-process-promise (and not q):

function spawnCmd(cmd, args, opts) {
    var opts = opts||{};
    console.log("[spawn]", cmd, args.join(' '), opts);

    var cmd_promise = spawn(cmd, args, opts);
    var child = cmd_promise.childProcess;

    child.stdout.on('data', function(chunk) {
        console.log("[" + cmd + ":stdout] " + chunk);
    });

    child.stderr.on('data', function(chunk) {
        console.log("[" + cmd + ":stderr] " + chunk);
    });

    return cmd_promise;
}

I also removed the "basename" part because it didn't happen to be necessary for my usecase.

Hope this is helpful to any Node newbs like me who find this through google search :)

very helpful @emhoracek 👍
I forked it and put the child-process-promise example there.