nixos/pleroma: create cookie if not existing (#149368)

nixos/modules/services/networking/pleroma.nix

@@ -100,6 +100,7 @@ in {
       after = [ "network-online.target" "postgresql.service" ];
       wantedBy = [ "multi-user.target" ];
       restartTriggers = [ config.environment.etc."/pleroma/config.exs".source ];
+      environment.RELEASE_COOKIE = "/var/lib/pleroma/.cookie";
       serviceConfig = {
         User = cfg.user;
         Group = cfg.group;
@@ -116,8 +117,14 @@ in {
         # has not been updated. But the no-op process is pretty fast.
         # Better be safe than sorry migration-wise.
         ExecStartPre =
-          let preScript = pkgs.writers.writeBashBin "pleromaStartPre"
-            "${cfg.package}/bin/pleroma_ctl migrate";
+          let preScript = pkgs.writers.writeBashBin "pleromaStartPre" ''
+            if [ ! -f /var/lib/pleroma/.cookie ]
+            then
+              echo "Creating cookie file"
+              dd if=/dev/urandom bs=1 count=16 | hexdump -e '16/1 "%02x"' > /var/lib/pleroma/.cookie
+            fi
+            ${cfg.package}/bin/pleroma_ctl migrate
+          '';
           in "${preScript}/bin/pleromaStartPre";
 
         ExecStart = "${cfg.package}/bin/pleroma start";