How to use the aws4.sign function in aws4

function request(options, cb) {
  if (typeof options === 'function') { cb = options; options = {} }
  cb = once(cb)
  for (var key in requestOpts) {
    if (options[key] === undefined)
      options[key] = requestOpts[key]
  }
  if (!options.noSign) {
    aws4.sign(options)
    options.noSign = true // don't sign twice if calling recursively
  }
  // console.log(options)
  (options.ssl ? https : http).request(options, function(res) {
    res.on('error', cb)
    var chunks = []
    res.on('data', function(chunk) { chunks.push(chunk) })
    res.on('end', function() {
      res.rawBody = Buffer.concat(chunks)
      if ((res.headers['content-type'] || '').indexOf('application/x-amz-cbor') !== 0) {
        res.body = res.rawBody.toString('utf8')
        try { res.body = JSON.parse(res.body) } catch (e) {} // eslint-disable-line no-empty
      } else {
        try { res.body = cbor.Decoder.decodeFirstSync(res.rawBody) } catch (e) {} // eslint-disable-line no-empty
      }
      if (res.body.__type == 'LimitExceededException' && /^Rate exceeded/.test(res.body.message))

var http  = require('http'),
    https = require('https'),
    aws4  = require('aws4')

// given an options object you could pass to http.request
var opts = {host: 'sqs.us-east-1.amazonaws.com', path: '/?Action=ListQueues'}

// alternatively (as aws4 can infer the host):
opts = {service: 'sqs', region: 'us-east-1', path: '/?Action=ListQueues'}

// alternatively (as us-east-1 is default):
opts = {service: 'sqs', path: '/?Action=ListQueues'}

aws4.sign(opts) // assumes AWS credentials are available in process.env

console.log(opts)
/*
{
  host: 'sqs.us-east-1.amazonaws.com',
  path: '/?Action=ListQueues',
  headers: {
    Host: 'sqs.us-east-1.amazonaws.com',
    'X-Amz-Date': '20121226T061030Z',
    Authorization: 'AWS4-HMAC-SHA256 Credential=ABCDEF/20121226/us-east-1/sqs/aws4_request, ...'
  }
}
*/

// we can now use this to query AWS using the standard node.js http API
http.request(opts, function(res) { res.pipe(process.stdout) }).end()

self._aws = opts
    return self
  }

  if (opts.sign_version === 4 || opts.sign_version === '4') {
    // use aws4
    var options = {
      host: self.uri.host,
      path: self.uri.path,
      method: self.method,
      headers: {
        'content-type': self.getHeader('content-type') || ''
      },
      body: self.body
    }
    var signRes = aws4.sign(options, {
      accessKeyId: opts.key,
      secretAccessKey: opts.secret,
      sessionToken: opts.session
    })
    self.setHeader('authorization', signRes.headers.Authorization)
    self.setHeader('x-amz-date', signRes.headers['X-Amz-Date'])
    if (signRes.headers['X-Amz-Security-Token']) {
      self.setHeader('x-amz-security-token', signRes.headers['X-Amz-Security-Token'])
    }
  } else {
    // default: use aws-sign2
    var date = new Date()
    self.setHeader('date', date.toUTCString())
    var auth = {
      key: opts.key,
      secret: opts.secret,

self._aws = opts
    return self
  }

  if (opts.sign_version == 4 || opts.sign_version == '4') {
    // use aws4
    var options = {
      host: self.uri.host,
      path: self.uri.path,
      method: self.method,
      headers: {
        'content-type': self.getHeader('content-type') || ''
      },
      body: self.body
    }
    var signRes = aws4.sign(options, {
      accessKeyId: opts.key,
      secretAccessKey: opts.secret
    })
    self.setHeader('authorization', signRes.headers.Authorization)
    self.setHeader('x-amz-date', signRes.headers['X-Amz-Date'])
  }
  else {
    // default: use aws-sign2
    var date = new Date()
    self.setHeader('date', date.toUTCString())
    var auth =
      { key: opts.key
      , secret: opts.secret
      , verb: self.method.toUpperCase()
      , date: date
      , contentType: self.getHeader('content-type') || ''

export function createPresignedURL(
  {
    host = process.env.AWS_IOT_HOST,
    path = '/mqtt',
    region = process.env.AWS_REGION,
    service = 'iotdevicegateway',
    accessKeyId = process.env.AWS_ACCESS_KEY_ID,
    secretAccessKey = process.env.AWS_SECRET_ACCESS_KEY,
    sessionToken = process.env.AWS_SESSION_TOKEN,
    // expires = 0, // @TODO: 300, check if this is working http://docs.aws.amazon.com/AmazonS3/latest/API/sigv4-query-string-auth.html
  } = {},
): string {
  const signed = aws4.sign(
    {
      host,
      path,
      service,
      region,
      signQuery: true,
      // headers: {
      //   'X-Amz-Expires': expires,
      // },
    },
    {
      accessKeyId,
      secretAccessKey,
    },
  )

self._aws = opts
    return self
  }

  if (opts.sign_version === 4 || opts.sign_version === '4') {
    // use aws4
    var options = {
      host: self.uri.host,
      path: self.uri.path,
      method: self.method,
      headers: {
        'content-type': self.getHeader('content-type') || ''
      },
      body: self.body
    }
    var signRes = aws4.sign(options, {
      accessKeyId: opts.key,
      secretAccessKey: opts.secret,
      sessionToken: opts.session
    })
    self.setHeader('authorization', signRes.headers.Authorization)
    self.setHeader('x-amz-date', signRes.headers['X-Amz-Date'])
    if (signRes.headers['X-Amz-Security-Token']) {
      self.setHeader('x-amz-security-token', signRes.headers['X-Amz-Security-Token'])
    }
  } else {
    // default: use aws-sign2
    var date = new Date()
    self.setHeader('date', date.toUTCString())
    var auth = {
      key: opts.key,
      secret: opts.secret,

signRequest(path, method) {
		const {accessKeyId, secretAccessKey, sessionToken} = this.session.resource;

		return aws4.sign({
			signQuery: true,
			service: 'imdbapi',
			region: 'us-east-1',
			method,
			host: API_BASE,
			path: `${path}?X-Amz-Security-Token=${encodeURIComponent(sessionToken).replace(/[!'()*]/g, escape)}`
		}, {
			accessKeyId,
			secretAccessKey
		});
	}

return new P(function(resolve, reject){
      if (!env || !env.accessKeyId || !env.secretAccessKey || !env.region ){
        reject(new Error('Config not complete. Run "shepherd config"'));
      } else {
        var mergedOpts = _.assign({ service: 'apigateway', region: env.region }, opts);
        aws4.sign(mergedOpts, env);
        var req = https.request(mergedOpts, function(response) {
          var body = '';
          response.on('data', function(d) { body += d; });
          response.on('end', function() {
            if (response.statusCode < 200 || response.statusCode > 299) {
              reject(body);
            } else {
              resolve(JSON.parse(body));
            }
          });
        });

        req.on('error', reject);
        req.end(opts.body || '');
      }
    });

async options => {
				const credentials = await chain.resolvePromise()
				aws4.sign(options, credentials)
			}
		]