I had some dashboards built in Python with Dash. They were using version 1.13.4 and I updated it to version 2.0.0. In addition to converting the imports, as explained in the migration guide, I also had to change state variables because I was getting the error:

ValueError: The state keyword argument may not be provided without the input keyword argument

I didn't understand the explanation in the migration guide. After reading the new documentation about callbacks, I've found that I had to change my app_callbacks. Previously, I had something like this:

@app.callback(
    Output(component_id='wl-plot', component_property='src'),
    [
        Input(component_id='sol-select', component_property='value'),
        Input(component_id='button-apply', component_property='n_clicks'),
    ],
    state=
    [
        State(component_id='base-dir', component_property='value'),
    ]
)

And I had to change it to this:

@app.callback(
    Output(component_id='wl-plot', component_property='src'),
    Input(component_id='sol-select', component_property='value'),
    Input(component_id='button-apply', component_property='n_clicks'),
    State(component_id='base-dir', component_property='value'),
)

So, basically, now you only have a list of Output, Input and State instances and you don need the state=....

I've found this script which is very handy to analyze if you Linux-based system is vulnerable to Spectre and Meltdown. I found this through this talk.

In a previous post I explained how to use Pelican with GitHub pages but didn't explain how to change the theme. I've changed it now to use Flex and it was harder than expected.

Most of the guides I've found talked about cloning pelican-themes in a folder on your system and changing the variable THEME to that folder. However, that doesn't work when you are using GitHub actions to build your site because it won't find that folder.

My solution was cloning the theme I wanted, Flex, to a folder inside the root folder of the blog:

git clone https://github.com/alexandrevicenzi/Flex

Then I set in pelicanconf.py the variable THEME as follows:

THEME = 'Flex'

In order to make it work with GitHub actions, I had to add in the file publi.sh, before calling pelican, this line:

git clone https://github.com/alexandrevicenzi/Flex

After commiting and pushing, it worked.

I've got a Kubernetes cluster prepared to be be integrated with Prometheus, i.e., all relevant information is exposed with /metrics and scraped by a Prometheus instance. I want to save the information long term and I've decided that Influx DB is the best option for that. In addition, I want to create dashboards using Grafana.

This would require moving the information from Prometheus to Influx DB. According to this, for Influx DB v1, this would be accomplished by using directly remote writes in Prometheus. However, Influx DB v2 doesn't allow this way of working. Instead, Telegraf has to be inserted in the middle. Therefore, the whole pipeline would be Prometheus 🠮 Telegraf 🠮 Influx DB 🠮 Grafana.

I'm using EKS to deploy the cluster, but these instructions should work with any other Kubernetes cluster. I'll only assume that kubectl is already configured to work with your cluster. We are going to deploy many services, so you may require new nodes in your cluster.

Helm

We'are going to use Helm for installing all the components, so first we …

So I guess my first blog should be about setting up this blog.

I wanted to use GitHub pages. By default they use Jekyll, which is built with Ruby. I have no experience with that language, so I tried to use something Python-based. I found this post about using Pelican, but I had some problems. I'm going to try to give here step by step instructions, using Linux.

Create a directory for the blog, an environment and activate it:

mkdir blog
cd blog
python -m venv .venv
source .venv/bin/activate

Install pelican with one of these options:

# This option only allows reStructuredText
python -m pip install pelican

# This allows markdown and reStructuredText
python -m pip install "pelican[markdown]"

Create the basic structure:

pelican-quickstart

I'll leave the standard theme. Read in the mentioned post if you want to change the theme.

Note I've created a new post about how to change the style to Flex

To test locally the blog, generate the site with:

make html

Now start a web server with:

make serve

You …