Automatically rip audio CDs

Config and scripts for automatically ripping audio CDs.

These scripts were assembled on a Raspberry Pi Zero W in 2017.

Once installed, they're designed to recognize when a CD is inserted and subsequently rip the audio CD. After ripping the CD, the scripts copy the files to Dropbox and trigger a Zapier webhook. You can easily edit the scripts to run whatever you want when the ripping is complete.

I will happily accept pull requests for changes and improvements and appreciate any input and suggestions. I'm not planning to build this beyond my personal needs but I hope it will be a useful resource for other people with similar goals.

Components

1. /etc/udev/rules.d/99-cd-audio-processing.rules This script tells udev what to do when a disc is inserted into the CD drive (sr0 here). This rule tells udev to run a systemd service.

   Call udevadm control --reload to force udev to load this rule for the drive without a reboot.

   We have to use a service instead of running the script directly because udev kills long running scripts. And we have to call /bin/systemctl instead of using SYSTEMD_WANTS because change events don't do the SYSTEMD_WANTS tasks.

2. /etc/systemd/system/rip-audio-cd@service This just wraps the actual CD ripping script in a systemd service.

3. /usr/local/sbin/rip-audio-cd.sh This script handles ripping and ejecting the CD, and prevents the script from running multiple times if there are multiple events. (I don't know if the locking is necessary with the udev setup. It's something I found in tutorials and kept.)

   The real work is being done by abcde, a command line ripping program. The script redirects the log and errors to /var/log/cdrip.log. If abcde throws an error, this script makes sure to call eject.

4. /etc/abcde.conf This is the configuration file for abcde. You can pass in flags but it's better (and standard) to set things up here. My configuration is set to rip files and encode them as both flac and mp3. It then puts the encoded files in /srv/ripped-music/flac and /srv/ripped-music/mp3.

   The post_encode() function sets up the rest of the work. It logs the artist and album name in /srv/ripped-music/last-rip.log for use by the remaining scripts, and then it runs the scripts.

5. /usr/local/bin/upload-to-dropbox.sh This script uses the Dropbox REST API and curl to add the files to Dropbox. (You may need to apt-get install curl.)

   You'll need a Dropbox bearer token for authentication. I created a Dropbox API app for myself (which only has access to its own folder in Dropbox), and then copied the bearer token from the API website. Just replace the **DROPBOX_BEARER_TOKEN** in the script with your actual token.

6. /usr/local/bin/add-to-airtable.sh This script would be more aptly named trigger-zapier.sh. It posts the artist and album as a JSON object to a Zapier webhook. The webhook is setup to add a row to an AirTable table. (Another Zapier trigger sends me an email when that new row is added.)

   You can create a new webhook trigger on the Zapier website. Just replace the **ZAPIER_WEBHOOK** in the script with the url for the webhook.

Installing

1. You'll need to install abcde and eject. You can use sudo apt-get -y install abcde eject. If you're encoding to flac and mp3 you'll also want to install lame and flac.

2. If you're testing this stuff while logged in (i.e., if you're running abcde or eject from the command line, you may need to add yourself to the cdrom group. eject didn't work for me without sudo otherwise. useradd -G cdrom $USERNAME

3. You might need to create the /srv/ripped-music directory where the files are saved, and you'll want to give permissions to the cdrom group so that you can write the files if you call abcde manually.

4. At this point, just copy the files to their respective places in the filesystem. That should be it.

Issues

Ripping Errors

Here's how I diagnose:

1. Check the log file /var/log/cdrip.log

2. Check the abcde status and errors files.

   abcde creates a temp folder in the root directory, /abcde.??? (where ??? is just to say that whatever follows the . is random). Usually that directory will contain a status file and sometimes an errors file with details.

   Sometimes cdparanoia, which abcde uses to rip the audio, throws errors when reading, which shuts down the whole script. I've had this happen on perfect, just opened CDs. I'm not sure how to fix this. Sometimes you can just put the CD back in and abcde will pick up where it left off. Some CDs just seem likethey can't move forward.

The annoying part of these errors is that the rest of the scripts still run, so it still gets uploaded to AirTable and the subset of songs that have completed are uploaded to Dropbox. As a result, I end up looking at the upload folder and manually checking to make sure the songs are there. It'd be nice to have an automated way to detect errors and flag them.

Auto-run Errors

Sometimes the scripts don't run on insertion. Here's what I do:

1. eject the CD and put it back in.
2. Check the status of the systemd service with systemctl status [email protected]
3. Restart the service with sudo systemctl restart [email protected]

Tagging / CDDB Errors

Some CDs haven't been found by the CDDB lookups. Not sure what to do with this yet. The script just rips them as Unknown Artist and Unknown Album and Track 1-N.

Album Art

In theory abcde supports getting and embedding the album art, but I haven't got it working yet.

Double Albums

This depends a bit on what's in the CDDB database. If both discs have the same album name, the files will get ripped to the same directory but both discs' tracks will be numbered starting at 1. Right now I'll probably fix it manually but an automated solution would be lovely.

General Linux Stuff

I put files a) where they worked and b) where they made sense based on what I could find on the web. I think in general all of these directories are appropriate, but I wouldn't be surprised if there are better places to put them.

References

• For ripping: https://somewideopenspace.wordpress.com/yet-another-headless-cd-ripper-and-mpd-on-raspberry-pi-installation-guide-yahcdramorpig/rip-music-from-cd/
• For abcde configuration: http://www.andrews-corner.org/linux/abcde/index.html
• For running when the disc is inserted: https://somewideopenspace.wordpress.com/yet-another-headless-cd-ripper-and-mpd-on-raspberry-pi-installation-guide-yahcdramorpig/start-ripping-when-cd-is-inserted/
• For the post_encode() stuff: https://lists.einval.com/pipermail/abcde-users/2015-June/000161.html
• For systemd and udev: https://forums.opensuse.org/showthread.php/485261-Script-run-from-udev-rule-gets-killed-shortly-after-start
• For understanding why SYSTEMD_WANTS wasn't what I needed: https://superuser.com/questions/862533/how-to-start-a-systemd-service-when-a-dvd-is-inserted/862575#862575 and https://www.raspberrypi.org/forums/viewtopic.php?f=28&t=151450&p=993856