45 lines
1.4 KiB
Nix
45 lines
1.4 KiB
Nix
# Pull-based NixOS updates for hosts that can't be pushed to reliably.
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# CI builds the system closure on muffin (which Harmonia serves), then
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# records the output store path at /deploy/<hostname>. On boot this
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# service fetches that path, pulls the closure from the binary cache,
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# and activates it.
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{ pkgs, hostname, ... }:
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let
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deploy-url = "https://nix-cache.sigkill.computer/deploy/${hostname}";
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pull-update = pkgs.writeShellScript "pull-update" ''
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set -euo pipefail
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STORE_PATH=$(${pkgs.lib.getExe pkgs.curl} -sf --max-time 30 "${deploy-url}" || true)
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if [ -z "$STORE_PATH" ]; then
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echo "Server unreachable or no deployment available, skipping"
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exit 0
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fi
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CURRENT=$(readlink -f /nix/var/nix/profiles/system)
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if [ "$CURRENT" = "$STORE_PATH" ]; then
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echo "Already on latest configuration"
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exit 0
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fi
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echo "Pulling update: $CURRENT -> $STORE_PATH"
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nix-store -r "$STORE_PATH"
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nix-env -p /nix/var/nix/profiles/system --set "$STORE_PATH"
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"$STORE_PATH/bin/switch-to-configuration" switch
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echo "Update applied"
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'';
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in
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{
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systemd.services.pull-update = {
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description = "Pull latest NixOS configuration from binary cache";
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after = [ "network-online.target" ];
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wants = [ "network-online.target" ];
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wantedBy = [ "multi-user.target" ];
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serviceConfig = {
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Type = "oneshot";
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ExecStart = pull-update;
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};
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};
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}
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