The core for asynchronous programming are the objects Task and Task<T>. Both of them are compatible with the keywords async and await.

First of all we need to identify if the code’s I/O-bound or CPU-bound.

• the code’s limited for external operations and waits for something a lot of time. Examples of this are DDBB calls, or a server’s response. In this case we have to use async/await to free the thread while we wait
• the code does a CPU-intensive operation. Then we move the work to another thread using Task.Run() so we don’t block the main thread.

async code vs parallel code

(!) Asynchronous code is not the same as parallel code (!)

• In async code you are trying to make your threads do as little work as possible. This will keep your app responsibe, capable to serve many requests at once and scale well.
• In parallel code you do the opposite. You use and keep a hold on a thread to do CPU-intensive calculations

async code

The importante of async programming is that you choose when to wait on a task. This way, you can start other tasks concurrently

In async code, one single thread can start the next task concurrently before the previous one completes.
(!) async code doesn’t cause additional threads to be created because an async method doesn’t run on its own thread. (!) It runs on the current synchronization context and uses time on the thread only when the method is active.

parallel code

For parallelism you need multiple threads where each thread executes a task, and all of those tasks are executed at the same time

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Working docker-compose and DockerFile examples to complement this information
Interesting tool to analyze custom Image layers size

Basic Definitions

Image Executable package that includes everything needed to run an application. It consists of read-only layers, each of which represent a DockerFile instruction. The layers are stacked and each one is a delta of changes from the previous layer.
Container Instance of an image.

Stack Defines the interaction of all the services
Services Image for a microservice which defines how containers behave in production

DockerFile File with instructions that allows us to build upon an already existing image. It defines:

• the base image to build from
• our own files to use or append
• the commands to run

At the end, a DockerFile will form a service, which we may call from docker-compose or standalone with docker build.

DockerFiles vs docker-compose A DockerFile is used when managing a single individual container. docker-compose is used to manage an application, which may be formed by one or more DockerFiles. Docker-compose may also be used as support to input large customization options, which otherwise would be parameters in a really long command.

You can do everything docker-compose does with just docker commands and a lot of shell scripting

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This are my Rust posts, as I wanted to test it briefly as a backend language.

1. From Java to Rust
2. Rust installation
3. Rust experience sheet

Config

• see config git config -l
• modify username git config --global user.name "newName"
• modify email git config --global user.mail "new@mail.com"

Git bisect

Is a tool to find the exact commit where a bug was introduced.

Usage

I have a file with the following content and an obvious bug

Row row row your car at the river

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Rest levels

Model of restful maturity used to help explain the specific properties of a web-style system.

Level 0

The starting point for the model is using HTTP as a transport system for remote interactions, but without using any of the mechanisms of the web.
We publish a document on how to use our API. We declare only one endpoint and do all the communication through this endpoint.

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Template

This is all needed to test.

package main

func main() {

}

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Check installation

go version

Environment variables

GOROOT
Folder where go was installated. It must only be set when installing to a custom location.

GOPATH
Place to get, build and install packages outside the standard Go Tree.

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Liquid is a template engine for HTML. It’s used by Jekyll.

Variables Usage

1. Declaration in a config.yml file with home_sidebar: Home
2. Usage with liquid in file.html as {{ site.home_sidebar }}

Functions

Show liquid code snippets

When writing liquid code snippets, jekyll process this code instead of showing it. To solve this, wrap the code snippet with the tags

{percent raw percent}
{percent endraw percent}

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Implementation of several patterns in Java, which may be used as future example on how to technically implement them.

Database

DAO & DTO

Data Access Object & Data Transfer Object. DAO - Design pattern, used to encapsulate the access to a persistence resource (e.g a database) and eliminate dependencies which come with the implementation of the code. DTO is the object which representates an entity of the database, with all its own properties to be manipulated.

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Which problem does it solve?

Since the beginning of my programming career, I’ve been writting small notes and how-to’s in Markdown. This approachhelps me avoid relearning the same thing twice and saves me from repeteadly searching for solutions for obscure problems.

Over time, this collection grew significantly, and I needed a more efficient way to index, access, and search through all my information. Building a website that also serves as a portfolio seemed like the best long-term solution.

Technology Stack

• Ruby
• Jekyll
• Liquid
• Markdown
• Gitlab CI/CD
• HTML, CSS, vanilla JS

Link

You’re inside.