Software, Cloud & DevOps

Hi! My name is Kim Lehtinen, and I’m a Software Engineer. I’m currently on a journey of specialising in backend development, and learning Cloud Native technologies. These technologies are truly powerful and changing the computing world. Here you can follow along on my journey where I write about things I’ve learned lately.

Task-based containers using Kubernetes Jobs

Apr 27, 2023

Containers Kubernetes

Containers Kubernetes Python

Containers are widely used for deploying and running applications. There are several benefits for containerizing applications. They offer a consistent environment for applications to be deployed to together with their dependencies. Containers are able to isolate workloads, and guarantee a certain amount of resources for each workload. In addition, they can be created fast, on the fly. This makes containers good for running resource-intensive workloads. Why not just use serverless? Serverless functions are great for events and on-demand services, and would probably be my first choice for smaller tasks.

Flask Unit Testing

Mar 31, 2023

Flask Python

Flask Python Testing

For the longest time I haven’t found good examples online on how to unit test Flask applications. Especially when following clean architecture, and when using dependency injection. That is why I decided to write this post. Flask is a minimalistic web framework, so I understand that most examples are small and simple. However, I know there are people out there building larger and more complex applications that requires good quality code, clean architecture and maintainability over time.

Flask database migrations using Flask-Migrate

Aug 1, 2022

Flask Python

Alembic Flask Python SQLAlchemy

Flask-Migrate is a python package that configures SQLAlchemy and Alembic for your Flask application. Alembic is the migration tool that actually takes care of database migrations under the hood. It can automatically generate migration files based on database schema models, and apply those migrations to databases. This is truly powerful, since it enables you to have a single source of truth and a history of your database changes in source control.

Python Flask Dependency Injection

Jul 15, 2022

Flask Python

One the best features of Flask is that it’s a “microframework”, meaning it’s easy to get started and to extend as the project grows. However, sometimes projects grow so large that it becomes hard to maintain all the dependencies and coupling between components. This is where dependency injection can help, by decoupling components and dependencies. This will make the code more reusable and easier to test through mocking the interfaces that a component uses.

Local Kubernetes cluster using kubeadm and Weave Ignite

Mar 9, 2022

Kubernetes

Kubernetes Kubeadm Ignite

As someone who is just learning Kubernetes, I want a local cluster where I can learn the basics of Kubernetes by testing and breaking things! I have lately been testing different tools for creating local kubernets clusters, and there are many good tools for doing so. However, many of them only spin up a single node cluster, I wanted multiple nodes. In addition, many tools make it difficult to control the amount of ram and cpu in each node.