Romulo Santos soeirosantos

Async functions in a usage context

The task we want to accomplish in this example is, given a URL and a file system path, download the document content and save it in the file system.

Let's begin our example by using the modules request and fs to perform the task directly:

const request = require('request')
const fs = require('fs')

If you are playing around with Kafka you, probably, would prefer to use containers. But, for some reason, you may want to use VMs instead. With this Vagrant script you can get a cluster installed and configured locally with a few steps.

Note that this script doesn't use the most recent version of Kafka. But you can change the version by changing the lines 12 and 13 of the script. Check the Confluent Platform and Apache Kafka Compatibilty table for details.

Instructions to execute and test

Install Virtual Box https://www.virtualbox.org/
Install Vagrant >= 1.6.4 http://www.vagrantup.com/

GKE Persistent Volumes

Let's play around with persistent volumes on GKE.

Setup stuff

$ gcloud init
<output_omitted>

	package br.com.soeirosantos;

	import java.util.LinkedList;
	import java.util.Queue;
	import java.util.Stack;

	public class Main {

	public static void main(String[] args) {
	System.out.println(isAlmostPalindrome("abcddcba", 0));

	#!/usr/bin/env python
	# -- coding: utf-8 --
	import feedparser, operator
	import re
	from stop_words import get_stop_words
	from time import gmtime, strftime

	stop_words = get_stop_words('en')

	OUTPUT_FOLDER = 'out/'

	double fixedCost = 0.1;
	double variableCost = 0.7;

	double totalCost = fixedCost + variableCost;

	System.out.println(totalCost);
	//output: 0.7999999999999999

	Integer[] array = {1, 1, 1, 2, 2, 2, 4, 4, 1, 1, 2, 5, 5,};
	Map<Integer, Long> collect =
	Arrays.stream(array).collect(
	Collectors.groupingBy(Function.identity(), Collectors.counting()));

	buildscript {
	ext {
	versions = [
	gradle : '3.2.1',
	springBoot : '1.4.3.RELEASE',
	springfox : '2.6.1',
	lombok : '1.16.10',
	lombok_plugin : '1.6',
	commons_io : '2.5',
	commons_lang : '3.4',

	package com.todevornot.hncounter

	import com.rometools.rome.io.SyndFeedInput
	import com.rometools.rome.io.XmlReader
	import java.net.URL

	val HN_URL = URL("https://news.ycombinator.com/bigrss")

	fun main(args: Array<String>) {

	/**
	It's a dummy example about how to synchronize the KafkaConsumer accross threads in scala.

	"The Kafka consumer is NOT thread-safe. All network I/O happens in the thread of the
	application making the call. It is the responsibility of the user to ensure that multi-threaded
	access is properly synchronized. Un-synchronized access will result in ConcurrentModificationException."
	- https://kafka.apache.org/0100/javadoc/org/apache/kafka/clients/consumer/KafkaConsumer.html#multithreaded

	*/