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I've been trying to set up writefreely to federate with my Mastodon instance but it's been fighting me. Debug logs showed a cryptic message attempting to follow myself failed to decode PEM block:

Nov 10 03:45:39 notvery writefreely[555357]: 2022/11/10 03:45:39 Fetching actor https://notvery.social/users/therabidbanana locally
Nov 10 03:45:39 notvery writefreely[555357]: 2022/11/10 03:45:39 Not found; fetching actor https://notvery.social/users/therabidbanana remotely
Nov 10 03:45:39 notvery writefreely[555357]: 2022/11/10 03:45:39 GET https://notvery.social/users/therabidbanana
Nov 10 03:45:39 notvery writefreely[555357]: ERROR: 2022/11/10 03:45:39 activitypub.go:808: Unable to get actor! failed to decode PEM block containing private key
Nov 10 03:45:39 notvery writefreely[555357]: ERROR: 2022/11/10 03:45:39 activitypub.go:413: Unable to resolve Follow: Couldn't fetch actor.

This error turns out to come from here: https://github.com/writeas/web-core/blob/fd1559928a0f11640eded30121574376c15a396e/activitypub/keys.go#L73

But why? This is a fresh install, and writefreely generated its own keys! Turns out it is calling out to openssl to do the actual generate, and Ubuntu 22 comes with OpenSSL 3 that uses a different key format. Had to go and manually insert some traditional style RSA keys to my database to make federation work here:

https://stackoverflow.com/questions/70266909/create-pkcs1-formatted-rsa-key-using-openssl-v3-0-0

Lessons learned getting started hosting my own Mastodon instance

Getting Started

It all started with a tweet pointing to runyourown.social. This has been sitting in my browser for nearly a year – but recent Twitter events finally made it seem worth investing time and effort into.

Honestly the hardest part was probably coming up with a good name for a fake social network. I'm not very creative, so I landed on https://notvery.social/

Installation

Mastodon (and therefore the Hometown fork) is Ruby on Rails and Sidekiq, which are pretty familiar territory for me. The guides for setting up a Linux server were very easy to follow along with.

The hardest bits to get going with were setting up a Linode to send email directly (had to follow along with a guide and also set up SPF and DKIM) and also using Linode Object Storage, supposedly S3 compatible, but with some non-intuitive setup for the options – the key one here being S3_OVERRIDE_PATH_STYLE:

S3_ENABLED=true
S3_PROTOCOL=https
S3_BUCKET=files.notvery.social
S3_REGION=us-southeast-1
S3_HOSTNAME=us-southeast-1.linodeobjects.com
S3_ENDPOINT=https://us-southeast-1.linodeobjects.com
S3_OVERRIDE_PATH_STYLE=true
AWS_ACCESS_KEY_ID=….
AWS_SECRET_ACCESS_KEY=...
S3_ALIAS_HOST=us-southeast-1.linodeobjects.com/files.notvery.social/

Setting Up

Once the server was able to upload files and send emails, it was pretty straightforward to set up – just needed to find some users to follow in the fediverse. There's a growing number of tools for finding follows from Twitter – but this one I found to be most effective:

https://pruvisto.org/debirdify

You can also find some other lists of people to follow floating around, but make sure to check whether the people want to be followed.

Extras

Mastodon provides OAuth 2 which makes it also able to log into other services pretty easily.

@darius@friend.camp came up with an RSS-to-Activity Pub converter we can use to pull in some news articles.

WriteFreely.org is a blogging platform that can be subscribed to by any Mastodon instances and also runs as a self-contained service (with SQLite) with OAuth for login (which Mastodon can provide).