Rust implementation of fatcat API server (`fatcatd`).

## Development

You need the following dependencies installed locally to build, run tests, and
do development work:

- rust stable, 1.29+ (eg, via "rustup", includes cargo tool)
- diesel (`cargo install diesel_cli`)
- postgres (9.6+; targetting 11.1 for production)
- postgres libs (debian: `sudo apt install libsqlite3-dev libpq-dev`)
- libsodium library and development headers (debian: `libsodium-dev`)

Copying commands out of `../.gitlab-ci.yml` file may be the fastest way to get
started.

Create a new postgres superuser. A regular postgres user and an existing
database should also work (with up/down migrations), but it's easier to just
blow the entire database away.

Copy `env.example` to `.env`, update if needed, then re-create database from
scratch:

    diesel database reset

Build and run:

    cargo run --bin fatcatd

Tests:

    cargo test -- --test-threads 1

See `HACKING` for some more advanced tips and commands.

## Configuration

All configuration goes through environment variables, the notable ones being:

- `DATABASE_URL`: postgres connection details (username, password, host, and database)
- `TEST_DATABASE_URL`: used when running `cargo test`
- `AUTH_LOCATION`: the domain authentication tokens should be valid over
- `AUTH_KEY_IDENT`: a unique name for the primary auth signing key (used to
  find the correct key after key rotation has occured)
- `AUTH_SECRET_KEY`: base64-encoded secret key used to both sign and verify
  authentication tokens (symmetric encryption)
- `AUTH_ALT_KEYS`: additional ident/key pairs that can be used to verify tokens
  (to enable key rotation). Syntax is like `<ident1>:<key1>,<ident2>:key2,...`.

To setup authentication with a new secret authentication key, run:

    cargo run --bin fatcat-auth create-key

then copy the last line as `AUTH_SECRET_KEY` in `.env`, and update
`AUTH_KEY_IDENT` with a unique name for this new key (eg, including the date).