dyn-gandi/README.md

# Dyn-Gandi
A DNS record updater for [Gandi's LiveDNS](https://api.gandi.net/docs/livedns/) API.
This script is heavily inspired by [dyn-gandi](https://github.com/Danamir/dyn-gandi).

## How it works
This script determines the the current IP address by querying the resolvers defined in the config file.
It then queries the subdomains' A records off of Gandi and compares their IP addresses to the current IP address.
Should the IP address of a subdomain's A record not match your current IP address it will be updated. The subdomain's A record will be created should it not already exist.

## Notes
Every invocation of the script causes at least 1 request to a resolver specified and 1 API call to Gandi per domain.
Updating a subdomain's A record is 1 API request per subdomain, even if they share the same domain.  
Resolvers are queried in the order specified until one returns a valid IP address.  
It is also possible to define a path to a file with the API key written in it. This is good for environments where the config file has to be shared like in a nix project.

## How to use
First, get your API key from https://account.gandi.net/en/users/USER/security where `USER` is your Gandi username.

The script looks for a config file at `$HOME/.config/dyn-gandi/config.log` or `/etc/dyn-gandi.conf` in that order. So create a file at one of these locations according to the schema below.

```json
{
  "api": {
    "<Your-API-Key>": {
      "example.com": [ "@", "www", "sub1" ],
      "example.org": [ "@", "www", "sub1", "sub2" ]
    },
    "/path/to/a/file/containing/api_key": {
      "example.at": [ "sub1" ],
      "example.au": [ "sub1", "sub2" ]
    }
  },
  "resolvers": [
    "https://ifconfig.me/ip",
    "https://me.gandi.net"
  ],
  "ttl": 3600,
  "log_path": "./log.txt"
}
```

## Nix
Add this to the modules.
```nix

inputs = {
  nixpkgs.url = "github:NixOS/nixpkgs/nixos-23.05";
  dyn-gandi.url = "git+https://git.krsnik.at/Kristian/dyn-gandi";
};

outputs = {
  self,
  nixpkgs,
  dyn-gandi
}: {
  ...
  modules = [
    dyn-gandi.nixosModules.default
    {
      dyn-gandi.enable = true;
      dyn-gandi.timer = 300;
      dyn-gandi.settings = {
        api = {
          "/path/to/a/file/containing/api_key" = {
            "example.com" = ["@" "www"];
          };
        };
        resolvers = [
          "https://ifconfig.me/ip"
          "https://me.gandi.net"
        ];
        ttl = 3600;
        log_path = "/path/to/log/file";
      };
    }
    ...
  ];
  ...
}
```
Use `dyn-gandi.nixosModules.default` for a NixOs module and `dyn-gandi.homeManagerModules.default` for home-manager

`dyn-gandi.timer` specifies a timer in seconds when the script should be repeated.


## Features
* Support for arbitrarily many domains and subdomains through a nested data structure.
* Small codebase
* Logging
* NixOS and home-manager modules

## Limitations
* Only IPv4 addresses are supported

## TODO
* Testing
* Command line options controlling: dry-run, config, log, verbosity, force
* Support IPv6
* Per subdomain TTL
* Better documentation
* Better logging