machines/nix/modules/nixos/services/read-vault-auth-from-userdata/default.nix

77 lines
2.9 KiB
Nix

{
config,
lib,
pkgs,
...
}:
let
cfg = config.khscodes.services.read-vault-auth-from-userdata;
in
{
options.khscodes.services.read-vault-auth-from-userdata = {
enable = lib.mkEnableOption "Enables reading vault auth information from instance userdata";
url = lib.mkOption {
type = lib.types.str;
description = "URL to retrieve instance metadata from";
};
};
config = lib.mkIf (cfg.enable && config.khscodes.services.vault-agent.enable) (
let
vault_addr = lib.escapeShellArg config.khscodes.services.vault-agent.vault.address;
secretIdFilePath = lib.escapeShellArg config.khscodes.services.vault-agent.vault.secretIdFilePath;
roleIdFilePath = lib.escapeShellArg config.khscodes.services.vault-agent.vault.roleIdFilePath;
cacheFilePath = lib.escapeShellArg "${config.khscodes.services.vault-agent.vault.secretIdFilePath}.wrapped";
in
{
systemd.services."read-vault-auth-from-userdata" = {
enable = true;
wantedBy = [ "multi-user.target" ];
wants = [ "network-online.target" ];
after = [ "network-online.target" ];
serviceConfig = {
Type = "oneshot";
RemainAfterExit = true;
ExecStart = lib.getExe (
pkgs.writeShellApplication {
name = "read-vault-auth-from-userdata";
runtimeInputs = [
pkgs.curl
pkgs.jq
pkgs.openbao
pkgs.getent
pkgs.systemd
];
text = ''
userdata="$(curl ${lib.escapeShellArg cfg.url})"
role_id="$(echo "$userdata" | jq --raw-output '.VAULT_ROLE_ID')"
secret_id_wrapped="$(echo "$userdata" | jq --raw-output '.VAULT_SECRET_ID_WRAPPED')"
if [[ -f ${cacheFilePath} ]]; then
cache_key="$(cat ${cacheFilePath})"
if [[ "$secret_id_wrapped" == "$cache_key" ]]; then
echo "Secret id matched last used value, exiting program"
exit 0
fi
fi
secret_id="$(BAO_ADDR=${vault_addr} bao unwrap -field=secret_id "$secret_id_wrapped")"
mkdir -p "$(dirname ${secretIdFilePath})"
mkdir -p "$(dirname ${roleIdFilePath})"
echo -n "$role_id" > ${roleIdFilePath}
echo -n "$secret_id" > ${secretIdFilePath}
chown root:root ${secretIdFilePath}
chmod 0600 ${secretIdFilePath}
chown root:root ${roleIdFilePath}
chmod 0600 ${roleIdFilePath}
echo -n "$secret_id_wrapped" > ${cacheFilePath}
chmod 0600 ${cacheFilePath}
chown root:root ${cacheFilePath}
echo "Role id and secret id copied, restarting vault-agent"
systemctl restart vault-agent-openbao.service
'';
}
);
};
};
}
);
}