Dy.fi client

This a dynamic DNS updater client for the Finnish dy.fi service. It is written in the Rust language and a fair bit overengineered. It serves as a bit of a portfolio project.

Configuration

Configuration options are read from environment variables. If a .env file exists in the current working directory, those are also read, but they will not overwrite environment variables already set.

The variables are:

• DYFI_USER
• DYFI_PASSWORD
• DYFI_HOSTNAMES – a comma-separated list of hostnames associated with the selected username

To control the log level, you may also set the RUST_LOG variable. By default only errors are logged, but RUST_LOG=dyfi_client=info enables logging successes as well.

Exit statuses

Status	Meaning
0	OK
1	Bad authentication.
2	No hostname given or hostname not allocated for user.
3	Not a valid FQDN.
4	IP not valid or not registered to a Finnish organisation.
5	Request failed due to technical problem.
6	Request denied due to abuse.
10	Initialization error - usually due to environment variables.

Building

Easiest is to build an image from the included Dockerfile.

Building conventionally on host OS

Install these prerequisites:

• Development packages for OpenSSL:
  • libssl-dev on Debian and Ubuntu
  • openssl-dev on Fedora
• The Rust toolchain

Run cargo build --release. The resulting binary will be in ./target/release/.

Running

The dy.fi client is a daemon that runs on a loop and keeps track of some state. State is not saved on disk, so starting the daemon always performs an update first and then sleeps.

Options:

1. Build and start a container from the included Dockerfile. A docker-compose.yml is also provided.

2. Run the daemon on your host system, e.g. as a systemd unit.

Dy.fi documentation

• https://www.dy.fi/page/clients
• https://www.dy.fi/page/specification

TODO

• Maybe save last performed update on disk. This would require a volume in Docker.