gulpfile.js

var AWS         = require('aws-sdk');
var gulp        = require('gulp');
var zip         = require('gulp-zip');
var install     = require('gulp-install');
var runSequence = require('run-sequence');
var fs          = require('fs');

var packageJson = require('./package.json');

//constants
var region       = 'eu-west-1';
var functionName = 'LambdaTest';
var outputName   = 'LambdaTest.zip';

var IAMRole      = 'arn:aws:iam::655240720487:role/lambda_basic_execution';
var filesToPack  = ['./lambda-testing/functions/LambdaTest.js'];

/**
 * Adds the project files to the archive folder.
 */
gulp.task('js', function () {
  return gulp.src(filesToPack, {base: './lambda-testing/functions'})
    .pipe(gulp.dest('dist/'));
});

/**
 * This task will copy all the required dependencies to
 * the dist folder.
 */
gulp.task('node-mods', function () {
  return gulp.src('./package.json')
    .pipe(gulp.dest('dist/'))
    .pipe(install({production: true}));
});

/**
 * Create an archive based on the dest folder.
 */

gulp.task('zip', function () {
  return gulp.src(['dist/**', '!dist/package.json'])
    .pipe(zip(outputName))
    .pipe(gulp.dest('./'));
});

/**
* Upload deployment package to S3 (lambda function file + dependencies)
*/
gulp.task('upload-to-s3', function () {
  var s3 = new AWS.S3();
  var zipFilePath = './' + outputName;
  getZipFile(function (data) {
    var params = {
      Bucket: 'lambda-function-container',
      Key: zipFilePath,
      Body: data
    };
    s3.putObject(params, function(err, data) {
      if (err) console.log('Object upload unsuccessful!');
      else console.log('Object ' + outputName + ' was uploaded!');
    });
  });
  function getZipFile (next) {
    fs.readFile(zipFilePath, function (err, data) {
          if (err) console.log(err);
          else {
            next(data);
          }
    });
  }
});

/**
 *  update or create the lambda functon
 */
gulp.task('upload', function() {
  AWS.config.region = region;
  var lambda = new AWS.Lambda();
  var s3 = new AWS.S3();
  var zipFile = './' + outputName;
  var bucketName = 'lambda-function-container';

  lambda.getFunction({ FunctionName: functionName }, function(err, data) {
    if (err) checkObject(createFunction);
    else checkObject(updateFunction);
  });
  function checkObject (fn) {
    var params = {
      Bucket: bucketName,
      Key: zipFile
    };
    s3.getObject(params, function (err, data) {
      if (err) console.log('BUCKET ERROR', err);
      else fn();
    });
  }
  function createFunction () {
      var params = {
        Code: {
          S3Bucket: bucketName,
          S3Key: zipFile
        },
        FunctionName: functionName,
        Handler: 'LambdaTest.handler',
        Role: IAMRole,
        Runtime: 'nodejs'
      };

      lambda.createFunction (params, function (err, data) {
        if (err) console.error("CREATE ERROR", err);
        else console.log('Function ' + functionName + ' has been created.');
      });

  }

  function updateFunction () {
      var params = {
        FunctionName: functionName,
        S3Bucket: bucketName,
        S3Key: zipFile
      };

      lambda.updateFunctionCode(params, function(err, data) {
        if (err) console.error(err);
        else console.log('Function ' + functionName + ' has been updated.');
      });
  }

});

gulp.task('test-invoke', function() {
  var lambda = new AWS.Lambda();

  var params = {
    FunctionName: functionName,
    InvocationType: 'RequestResponse',
    LogType: 'Tail',
    Payload: '{ "key1" : "name" }'
  };

  lambda.getFunction({ FunctionName: functionName }, function(err, data) {
    if (err) console.log("FUNCTION NOT FOUND", err);
    else invokeFunction();
  });

  function invokeFunction() {
    lambda.invoke(params, function(err, data) {
      if (err) console.log(err, err.stack);
      else console.log(data);
    })
  }
})


gulp.task('deploy', function (callback) {
  return runSequence(
    ['js', 'node-mods'],
    ['zip'],
    ['upload-to-s3'],
    ['upload'],
    ['test-invoke']
    callback
  );
});