feat(sterni/machines): add edwin r/5336

This adds edwin, the machine running sterni.lv, as well as my
idiosyncratic deployment solution. It is based on instantiating the
system configuration locally (where you'd work on the configuration),
copying the derivation files to the remote machine where the system
derivation is realised and deployed. Unfortunately, the first step tends
to be quite slow (despite gzip compression), so this may not be the
definite way despite its advantages.

Change-Id: I30f597692338df3981e01a1b7eee9cdad48f94cb
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7293
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI

1 files changed, 77 insertions, 0 deletions

diff --git a/users/sterni/machines/default.nix b/users/sterni/machines/default.nix
new file mode 100644
index 000000000000..4a859a337a22
--- /dev/null
+++ b/users/sterni/machines/default.nix
@@ -0,0 +1,77 @@
+{ depot, lib, pkgs, ... }:
+
+let
+  bins = depot.nix.getBins pkgs.nq [ "fq" "nq" ];
+
+  machines = lib.mapAttrs
+    (name: _:
+      depot.ops.nixos.nixosFor (import (./. + ("/" + name)))
+    )
+    (lib.filterAttrs (_: type: type == "directory") (builtins.readDir ./.));
+
+  # TODO(sterni): share code with rebuild-system
+  localDeployScriptFor = { system, ... }:
+    pkgs.writeShellScript "local-deploy-${system.name}" ''
+      set -eu
+      nix-env -p /nix/var/nix/profiles/system --set "${system}"
+      "${system}/bin/switch-to-configuration" switch
+    '';
+
+  # Builds the system on the remote machine
+  deployScriptFor = { system, ... }@machine:
+    pkgs.writeShellScript "remote-deploy-${system.name}" ''
+      set -eu
+
+      if [ $# != 1 ]; then
+        printf 'usage: %s [USER@]HOST' "$0"
+        exit 100
+      fi
+
+      readonly TARGET_HOST="$1"
+      readonly DEPLOY_DRV="${
+        builtins.unsafeDiscardOutputDependency (
+          # Wrapper script around localDeployScriptFor that merely starts the
+          # local deploy script using and nq and then waits using fq. This means
+          # we can't Ctrl-C the deploy and it won't be terminated by a lost
+          # connection.
+          pkgs.writeShellScript "queue-deploy-${system.name}" ''
+            readonly STATE_DIR="''${XDG_STATE_HOME:-$HOME/.local/state}/sterni-deploy"
+            mkdir -p "$STATE_DIR"
+
+            export NQDIR="$STATE_DIR"
+
+            "${bins.nq}" "${localDeployScriptFor machine}"
+            "${bins.fq}"
+          ''
+        ).drvPath
+      }"
+
+      nix-copy-closure -s --gzip --to "$TARGET_HOST" "$DEPLOY_DRV"
+
+      readonly DEPLOY_OUT="$(ssh "$TARGET_HOST" "nix-store -r '$DEPLOY_DRV'")"
+
+      ssh "$TARGET_HOST" "$DEPLOY_OUT"
+    '';
+
+in
+
+depot.nix.readTree.drvTargets (
+  # this somehow becomes necessarily ugly with nixpkgs-fmt
+  machines // { inherit deployScriptFor; } //
+
+  lib.mapAttrs'
+    (name: _: {
+      name = "${name}System";
+      value = machines.${name}.system;
+    })
+    machines
+
+    //
+
+  lib.mapAttrs'
+    (name: _: {
+      name = "${name}Deploy";
+      value = deployScriptFor machines.${name};
+    })
+    machines
+)