2701665904
Since we're already fetching one datum, we may as well fetch the others needed by fetch-ec2-data. This also eliminates the dependency on wget.
49 lines
1.5 KiB
Nix
49 lines
1.5 KiB
Nix
{ config, pkgs, modulesPath, ... }:
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# This attempts to pull a nix expression from this EC2 instance's user-data.
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let
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bootScript = pkgs.writeScript "bootscript.sh" ''
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#!${pkgs.stdenv.shell} -eu
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echo "attempting to fetch configuration from EC2 user data..."
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export PATH=${config.nix.package}/bin:${pkgs.systemd}/bin:${pkgs.gnugrep}/bin:${pkgs.gnused}/bin:${config.system.build.nixos-rebuild}/bin:$PATH
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export NIX_PATH=/nix/var/nix/profiles/per-user/root/channels/nixos:nixos-config=/etc/nixos/configuration.nix:/nix/var/nix/profiles/per-user/root/channels
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userData=/etc/ec2-metadata/user-data
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if [ -s "$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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boot.postBootCommands = ''
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${bootScript} &
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'';
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}
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