rsstotwitter is an application that posts stories from an RSS feed to Twitter.

There is an experimental web interface (which by default runs on port 8080) where I am learning how to do that type of work in Go.

rsstotwitter started out as a specific application to post news stories from lobste.rs to Twitter.

The first version was written in 92 source lines of code in Python, and is a fairly basic system based on SQLite. I've been learning Go lately, and needed a project to work on, preferably writing some type of webapp as that is an area I have no experience in. Ergo, the decision to rewrite lobsterpie in Go.

rsstotwitter is comprised of two main components, bot (the backend) and frontend. The backend employs a worker pool using goroutines and channels, while the frontend simply displays the last time the bot updated.

The backend starts up the worker pool, which communicate via a channel for new stories. This channel is written to by the RSS feed parser, which is in a separate goroutine. When the RSS feed is updated, it reads the entries, converts them to the internal data structure that represents a story, and writes that to the channel. The next available worker picks it up, checks whether the story has already been posted, and if not, posts the story to Twitter and marks the story as read in the database. Reading from a channel blocks, so each worker essentially sleeps while waiting for new stories.

The code is designed to be deployable to Heroku, and uses a Postgres database that is configurable from the environment. As the application effectively only has one user, the transaction cost isn't an issue.

I had originally wanted to use Redis as the datastore, but Heroku's Redis addon costs money. This app generates no revenue, so I didn't want to end up paying for keeping it running; Redis also requires an SSL tunnel in order to communicate securely with remote datastores which would end up being a hassle to setup. I already had a VPS set up with Postgres, so I ended up just using that. It is overkill, as the table merely stores the guid of the story, but the infrastructure was already in place, and therefore the decision to base this on Postgres.

See also the DEPLOYMENT.md file that ships with the source code.

You will need to run tools/customise.sh in the project root to properly set up imports.