62 lines
1.8 KiB
Nix
62 lines
1.8 KiB
Nix
{ config, pkgs, ... }:
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let
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script = ''
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#!${pkgs.runtimeShell} -eu
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echo "attempting to fetch configuration from EC2 user data..."
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export HOME=/root
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export PATH=${pkgs.lib.makeBinPath [ config.nix.package pkgs.systemd pkgs.gnugrep pkgs.gnused config.system.build.nixos-rebuild]}:$PATH
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export NIX_PATH=/nix/var/nix/profiles/per-user/root/channels/nixos:nixos-config=/etc/nixos/configuration.nix:/nix/var/nix/profiles/per-user/root/channels
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userData=/etc/ec2-metadata/user-data
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if [ -s "$userData" ]; then
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# If the user-data looks like it could be a nix expression,
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# copy it over. Also, look for a magic three-hash comment and set
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# that as the channel.
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if sed '/^\(#\|SSH_HOST_.*\)/d' < "$userData" | grep -q '\S'; then
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channels="$(grep '^###' "$userData" | sed 's|###\s*||')"
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printf "%s" "$channels" | while read channel; do
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echo "writing channel: $channel"
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done
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if [[ -n "$channels" ]]; then
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printf "%s" "$channels" > /root/.nix-channels
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nix-channel --update
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fi
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echo "setting configuration from EC2 user data"
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cp "$userData" /etc/nixos/configuration.nix
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else
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echo "user data does not appear to be a Nix expression; ignoring"
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exit
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fi
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else
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echo "no user data is available"
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exit
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fi
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nixos-rebuild switch
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'';
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in {
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systemd.services.amazon-init = {
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inherit script;
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description = "Reconfigure the system from EC2 userdata on startup";
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wantedBy = [ "multi-user.target" ];
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after = [ "multi-user.target" ];
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requires = [ "network-online.target" ];
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restartIfChanged = false;
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unitConfig.X-StopOnRemoval = false;
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serviceConfig = {
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Type = "oneshot";
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RemainAfterExit = true;
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};
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};
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}
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