One common cause of bugs in many applications is that development and production environments differ. Although in most cases it’s not possible to provide an exact copy of the production environment for development, pursuing dev-prod parity is a worthwhile cause. Most web applications are deployed to some sort of Linux VM. If you’re using a traditional web-host, this is referred to as VPS hosting. If we want to develop in an environment similar to our production environment, how could we approach this? The closest would be to set up a second VM for development purposes. So let’s have a look t

In the previous blog post in this series, I created a Vagrant VM and provisioned it with Ansible for Python development. In this part, we’ll have a look at a larger application which is configured in the same way. In this post, I’ll introduce an application that I’ll be using for more blog posts in the future, so let me know in the comments if you have any cool ideas about what can be done to make this application better. We’ll use the following: Flask Flask-RESTful PostgreSQL, and pgmigrate for migrations The Ubuntu, Vagrant, Ansible stack introduced in the blog post last we

One of the things that could make developing cloud applications hard, would be differences between the dev environment and the production environment. This is why one of the factors of the twelve factor app is maintaining dev-prod parity. Today we’ll start a blog series about developing cloud applications, and we’ll discuss how to set up a local development environment using Vagrant. We’ll use these technologies for this application: Vagrant Ansible Flask Virtualenv Ubuntu Today we'll just create a simple Flask application that'll say 'Hello world'. In the next post in th

Security is important, and that’s why we all use key pairs when authenticating to our servers. And as is best practice, we also protect our private key with a passphrase, don’t we? Ideally the passphrase is long and complicated, and therefore a massive pain to type. So how can we be lazy while still maintaining security? SSH Agent is the answer! Rather than typing the passphrase to your key individually for every connection, we can type it only once when we turn the computer on, and then SSH agent will keep the decrypted key safe in memory. Let’s have a look how to do this on Windows, Mac, an

By popular demand, PyCharm 2017.2 Professional Edition expands its Docker Compose support to those of you who run Windows. Let’s take a look and see how this works! In our last Docker Compose post, we created a guest book in Flask. This time we’ll take a simple todo app in Django, and dockerize it. The starting point today will be a Django todo app which works locally, see the code on GitHub. Setting Up Docker on Windows If you don’t have Docker installed yet, you’ll need to make a decision about which version to install: Are you using anything other than Windows 10 Pro or Enterprise, or

Last week we created a script that records ping times on a regular basis. We developed the script remotely on a Raspberry Pi, and then added it to Cron to make sure that times are recorded every 5 minutes into a PostgreSQL database. This week we’ll work on visualizing the data we’ve recorded. For this we’ll create a basic Flask app where we use Matplotlib to create a graph. Furthermore, we’ll take a look at some cool PostgreSQL features. Let’s see some results It’s no good to just record pings if we can’t see some statistics about them, so let’s write a small Flask app, and use matplotlib to d