Just some notes from my attempt at setting up Hydra.
No need for manual database creation and all that; just ensure that your PostgreSQL service is running (services.postgresql.enable = true;), and then enable the Hydra service (services.hydra.enable). The Hydra service will need a few more options to be set up, below is my configuration for it:
services.hydra = {
enable = true;
port = 3333;
hydraURL = "http://localhost:3333/";
notificationSender = "hydra@cryto.net";
useSubstitutes = true;
minimumDiskFree = 20;
minimumDiskFreeEvaluator = 20;
};
Database and user creation and all that will happen automatically. You'll only need to run hydra-init and then hydra-create-user to create the first user. Note that you may need to run these scripts as root if you get permission or filesystem errors.
If you already have a services.postgresql.authentication configuration line from elsewhere (either another service, or your own configuration.nix), it may be conflicting with the one specified in the Hydra service. There's an open issue about it here.
After running hydra-create-user in your shell, you may be running into the following error in the web interface: "Bad username or password."
When this occurs, it's likely because the hydra-* utility scripts stored your data in a local SQLite database, rather than the PostgreSQL database you configured. As far as I can tell, this happens because of some missing HYDRA_* environment variables that are set through /etc/profile, which is only applied on your next login. Simply opening a new shell is not enough.
As a workaround until your next login/boot, you can run the following to obtain the command you need to run to apply the new environment variables in your current shell:
cat /etc/profile | grep set-environment... and then run the resulting command (including the dot at the start, if there is one!) in the shell you intend to run the hydra-* scripts in. If you intend to run them as root, make sure you run the set-environment script in the root shell - using sudo will make the environment variables get lost, so you'll be stuck with the same issue as before.
Aha! Thanks, this saved me probably hours of time