The Dev World – Sergio Lema

Author: Sergio Lema

  • How to Calculate the Servers Sizes for my Microservices

    How to Calculate the Servers Sizes for my Microservices

    —

    by

    Sergio Lema
    in

    In this article I show how to calculate the size of a microservices cluster. Taking into account the CPU and memory capacity for the servers and for the services of my cluster.

  • Authenticate Your Angular Application with JWT

    Authenticate Your Angular Application with JWT

    —

    by

    Sergio Lema
    in

    In this article, I create an Angular application protected by JWT. I create a public component, private component and login component to show the different usages of each one. I use the JWT with the requests to my backend in the HTTP headers.

  • Microservices Communications

    Microservices Communications

    —

    by

    Sergio Lema
    in ,

    Here is a list of the most used communictions protocols in microservices architecture. REST, a commonly used protocol, is simple and synchronous. SOAP uses XML and is often more verbose. RPC uses binary format, offering fast and compact communication. Messages or queues allow asynchronous communication, but require a message broker. Lastly, database communication uses a…

  • My Problems with Flyway

    My Problems with Flyway

    —

    by

    Sergio Lema
    in

    How I’ve created a framework to solve the most common problems with the Flyway migrations. I must first identify the problem from the log files. Then apply the solution depending on the problem. It can go from a simple changeset rollback to stop the production.

  • Microservices vs Serverless

    Microservices vs Serverless

    —

    by

    Sergio Lema
    in ,

    Microservices and Serverless Architectures, advantages and drawbacks. Microservices Architecture allows different teams to work on various services, but requires a deep understanding of network and service orchestration. Serverless Architecture allows for automatic scaling and load calibration, but can make database connections more complex.

  • Stop Using Null on Database Rows

    Stop Using Null on Database Rows

    —

    by

    Sergio Lema
    in

    Stop Using Null on Database Rows. In this article I show why it’s a bad idea, what problem I’ve encountered and what is the solution I used.

  • Protect your Spring Boot application with JWT

    Protect your Spring Boot application with JWT

    —

    by

    Sergio Lema
    in

    The article provides a comprehensive guide on how to protect a Spring Boot application using JWT and Spring Security. It offers a detailed explanation on various aspects, including adding dependencies, encoding passwords, creating login endpoints, JWT HTTP filtering, and configuring Spring Security. It also emphasizes the importance of having protected routes and a HTTP filter…

  • Implement the CRUD Operations in Angular

    Implement the CRUD Operations in Angular

    —

    by

    Sergio Lema
    in

    The article explains setting up CRUD operations in an Angular frontend for a vehicle management system, paired with a Spring Boot backend. The tutorial breaks down each CRUD operation: Read, Create, Delete, and Update, detailing how to display data using Material components, form creation for data upload, data deletion, and updating existing data. It also…

  • The Hardest Bug I’ve Faced

    The Hardest Bug I’ve Faced

    —

    by

    Sergio Lema
    in

    In this article, I will describe some of the worst bugs that happen in an application. Let’s start by splitting them into two main categories: those which I can reproduce on my laptop, and those I can’t reproduce on my laptop.

  • PostgreSQL’s Deadlocks

    PostgreSQL’s Deadlocks

    —

    by

    Sergio Lema
    in

    Have you ever faced a database deadlocks in Postgres? In this article, I will tell a story about the deadlocks, A Journey Through PostgreSQL’s Conundrums.