cluster/services/storage: externalize garage layout implementation

cluster/services/storage/default.nix

@@ -18,6 +18,7 @@ in
       heresy = [ ./heresy.nix ];
       garage = [
         ./garage.nix
+        ./garage-options.nix
         ./garage-layout.nix
       ];
       garageInternal = [ ./garage-internal.nix ];

cluster/services/storage/garage-layout.nix

@@ -1,13 +1,3 @@
-{ config, ... }:
-
-let
-  initialLayout = ''
-    garage layout assign -z eu-central -c 1000 28071b8673ad14c2 # checkmate
-    garage layout assign -z eu-central -c 1000 124d6acad43e5f70 # prophet
-    garage layout assign -z eu-central -c 1000 e354a1a70adc45c9 # VEGAS
-  '';
-in
-
 {
   system.ascensions.garage-layout = {
     distributed = true;
@@ -16,24 +6,9 @@ in
     incantations = i: [ ];
   };
 
-  systemd.services.garage-layout-init = {
-    distributed.enable = true;
-    wantedBy = [ "garage.service" ];
-    after = [ "garage.service" ];
-    path = [ config.services.garage.package ];
-
-    script = ''
-      while ! garage status >/dev/null 2>/dev/null; do
-        sleep 1
-      done
-
-      if [[ "$(garage layout show | grep -m1 '^Current cluster layout version:' | cut -d: -f2 | tr -d ' ')" != "0" ]]; then
-        exit 0
-      fi
-
-      ${initialLayout}
-
-      garage layout apply --version 1
-    '';
+  services.garage.layout.initial = {
+    checkmate = { zone = "eu-central"; capacity = 1000; };
+    prophet = { zone = "eu-central"; capacity = 1000; };
+    VEGAS = { zone = "eu-central"; capacity = 1000; };
   };
 }

cluster/services/storage/garage-options.nix

@@ -0,0 +1,77 @@
+{ config, lib, ... }:
+
+let
+  cfg = config.services.garage;
+
+  garageShellLibrary = /*bash*/ ''
+    getNodeId() {
+      nodeId=""
+      while [[ -z "$nodeId" ]]; do
+        nodeId="$(garage status | grep 'NO ROLE ASSIGNED' | grep -wm1 "$1" | cut -d' ' -f1)"
+        if [[ $? -ne 0 ]]; then
+          echo "Waiting for node $1 to appear..." 2>/dev/null
+          sleep 1
+        fi
+      done
+      echo "$nodeId"
+    }
+    waitForGarage() {
+      while ! garage status >/dev/null 2>/dev/null; do
+        sleep 1
+      done
+    }
+  '';
+in
+
+{
+  options.services.garage.layout = {
+    initial = lib.mkOption {
+      default = {};
+      type = with lib.types; attrsOf (submodule {
+        options = {
+          zone = lib.mkOption {
+            type = lib.types.str;
+          };
+          capacity = lib.mkOption {
+            type = lib.types.ints.positive;
+          };
+        };
+      });
+    };
+  };
+
+  config = {
+    system.extraIncantations = {
+      runGarage = i: script: i.execShellWith [ config.services.garage.package ] ''
+        ${garageShellLibrary}
+        waitForGarage
+        ${script}
+      '';
+    };
+
+    systemd.services.garage-layout-init = {
+      distributed.enable = true;
+      wantedBy = [ "garage.service" ];
+      after = [ "garage.service" ];
+      path = [ config.services.garage.package ];
+
+      serviceConfig = {
+        TimeoutStartSec = "1800s";
+      };
+      script = ''
+        ${garageShellLibrary}
+        waitForGarage
+
+        if [[ "$(garage layout show | grep -m1 '^Current cluster layout version:' | cut -d: -f2 | tr -d ' ')" != "0" ]]; then
+          exit 0
+        fi
+
+        ${lib.concatStringsSep "\n" (lib.mapAttrsToList (name: layout: ''
+          garage layout assign -z '${layout.zone}' -c '${toString layout.capacity}' "$(getNodeId '${name}')"
+        '') cfg.layout.initial)}
+
+        garage layout apply --version 1
+      '';
+    };
+  };
+}