Busy hands | Disquiet mind

So simply joining an existing mastodon instance is not enough for you, you want control? Set up your own! The official documentation has a page about that, including listing a bunch of specialised hosting providers that will do this installation bit for you. But we like the more difficult road with the rewarding learning curve around here. Make sure you get get your linux box prepared, and we'll get into setting up a mastodon instance on local hardware, running linux, without docker, and without cloud storage.

Step 1; Get to installing mastodon

( Details )

Step 2; Get to customising mastodon

( Details )

Step 3; Should you set up an instance for other people?

( Details )

Let's Encrypt's root cert expired the end of September just gone.

For the first time since then I tried running an old python script on a Raspberry Pi. It failed with an all too familiar error message. In both python3, and with curl.

I never see these errors in my browser (because Firefox is great like that). Even when I didn't have the certs on my site fully configured it didn't matter because Firefox had the necessary root and intermediate certs.

So I tried curl on my Windows machine, and it worked, no errors. Okay, it's not the configuration of my site. It's the Raspberry Pi. I need to update its cert cache.

I found most of what I needed here. The certs I want are here. (We'll be picking up local certs, so changing into the same directory is important.)

sudo mkdir /usr/share/ca-certificates/local
cd /usr/share/ca-certificates/local

sudo wget https://letsencrypt.org/certs/isrgrootx1.pem
sudo wget https://letsencrypt.org/certs/lets-encrypt-r3.pem

sudo openssl x509 -inform PEM -in isrgrootx1.pem -outform PEM -out isrgrootx1.crt
sudo openssl x509 -inform PEM -in lets-encrypt-r3.pem -outform PEM -out lets-encrypt-r3.crt

sudo dpkg-reconfigure ca-certificates

When prompted choose 'ask'. Mark your new certs with an asterisk, choose 'ok', and wait for it to finish.

Test by trying that curl command again. All goes well, no more errors!

Great, let's try that script again. Nope! More errors. Now that our Raspberry Pi has the correct certs we need to update the python certs. Enter an interactive session and find out where it keeps these certs.

python3
import certifi
certifi.where()

It says '/home/pi/.local/lib/python3.7/site-packages/certifi/cacert.pem'. Let's replace it!

rm /home/pi/.local/lib/python3.7/site-packages/certifi/cacert.pem
cp /etc/ssl/certs/ca-certificates.crt /home/pi/.local/lib/python3.7/site-packages/certifi/cacert.pem

Test by trying that python3 script again. All goes well, no more errors! Hopefully for real this time.

I am fed up of expensive handheld devices (phone, tablet, etc) working great for a year or two, and then slowing down, and down, and becoming unreliable, or having support suspended. I need a more open solution, on which I can install the mandatory Android apps to be able to use the hardware I have purchased that only communicate over bluetooth low-energy. For example, my activity tracker. What do I have to hand?

At the back of the cupboard I found my old pi-topCEED, which is a Raspberry Pi 3 Model B, with custom hub and accessories (like speakers, breakout boards), together with a display, in a custom case. (Specs here.) I love the form factor. It's just so neat. (No, it's not a touch-screen, but that doesn't stop people from trying.) Just add a mouse and keyboard and you have a full desktop computer set up. It has it's own OS, a flavour of debian, that is very targeted at kids. But I can always install a different OS on a another SD card.

To run the apps I need Android. I have an old Raspberry Pi. After some searching I found a MagPi issue from when the board was new. It has two suggestions; Emteria.OS and Android Things. I can't install the Play Store on Android Things, so that's out. I tried Emteria.OS. You have to sign up to get a trial download, and full versions need to be paid for, but if you can live with the restrictions this is an option. The install went very smoothly, but it is only Android 7. We must be able to do better.

So how about an unofficial LineageOS Raspberry Pi port by KonstaKANG? It looks like Raspberry Pi 3 support is topped out at LineageOS 17.1, which is Android 10. I gave it a go and everything goes pretty smoothly. Mostly. I encountered a problem on power up, after the rainbow square appears nothing else happens. I set the magic config.txt settings for the pi-topCEED, but no joy. (I did learn a lot about the various video options along the way though.) Eventually I found the thing I needed in the instructions themselves; I (also?) needed to set the resolution in the resolution.txt file. Then it booted up fine and I was flying. Until I installed the Play Store. Now, the instructions do warn against this, but I had to try it. And, yes. It does work, but it is incredibly, almost unusably slow. So if I really want to make this work I'm going to need to get my hands on a Raspberry Pi 4. Project paused.

( Photographic proof )

But, even when I get the Raspberry Pi 4, can I use the pi-topCEED custom hardware with it? Turns out no. I would need to have a debian compatible package manager, with which to install the pi-top repos. The future Android Raspberry Pi 4 is not destined for a fancy home in the pi-topCEED. But now I know I can install those repos on Raspberry Pi OS! A nice option to keep the Raspberry Pi 3 occupied.

I have VLC running on a headless system, in the form of the Pimoroni Pirate Radio. You can easily setup the radio station playlist by creating editing /etc/vlcd/default.m3u or /home/pi/.config/vlc/playlist.m3u. But what about adding local files to the Media Library? All the posts assume a graphical interface, so this took a little digging.

You will want to edit;
sudo vim /usr/bin/vlcd

To add on command line options for customisation. If you simply add the paths you want included to the end of the list they'll be included on reboot. But it doesn't get them into the actual Media Library section so instead I just disabled it, and enabled playlist trees for a nice folder structure.

( code )

In Pi Life, part one I only got as far as making my raspberry pi functional again through upgrade. Now on to the script I want to put on it.

After doing a project, and writing it up, I am usually too lazy to tweet my own blog posts, so I wrote a little python script to scrape my RSS feed and post a link to the most recent post to twitter. (For people who don't use RSS.)


Step Two; create twitter app entry and get access tokens

This part seems to change constantly, so here are some posts I used to help me along the way;
https://www.digitalocean.com/community/tutorials/how-to-create-a-twitter-app
https://iag.me/socialmedia/how-to-create-a-twitter-app-in-8-easy-steps/
https://code.tutsplus.com/articles/creating-a-twitter-oauth-application--net-16614


Step Three; create python script

Assuming you have python3 already;
pip3 install tweepy
pip3 install feedparser
pip3 install bs4
pip3 install lxml

And because BeautifulSoup can't seem to find lxml this way;
sudo apt-get install python3-lxml

Create a python script something like this (the exact code will depend on the structure of your RSS);
( code )


Step Four; deal with errors

My main error happened when I wanted to get an image used in a post. My images are self-hosted, Let's Encrypt signed. And the python3 libraries were not happy;
ssl.SSLCertVerificationError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: unable to get local issuer certificate (_ssl.c:1056)

Now you can just turn off verification;
response = get(img_link, verify=False)
But you still get an annoying warning message.

I tried so many different ways to try and fix this. This is the only thing I found that worked.

First, go to Let's Encrypt Certs and save the Intermediate, Active, cross-signed cert. Remove the .txt suffix. Verify this cert fixes the error for you with;
curl https://your_website --cacert /path/to/lets-encrypt-x3-cross-signed.pem
If no errors, all good.

Now, in python;
import certifi
print(certifi.where())

Mine returns /home/pi/.local/lib/python3.7/site-packages/certifi/cacert.pem
Edit this file, append everything in lets-encrypt-x3-cross-signed.pem to the end. (Leave a comment telling yourself what you did for future.) Save and exit. Rerun the tweeting python script.


Step Five;

Glory in the lack of errors/warnings. And automatically created tweets, I guess.