nixos/firefox-syncserver: fix setup failure due to duplicate key

in some circumstances, the setup service would fail with:
ERROR 1062 (23000) at line 5: Duplicate entry '1' for key 'PRIMARY'
so let's use an upsert instead of insert. This also simplifies the
script.

Besides, also fix that when the setup script changes, the corresponding
script is not restarted as it is usually not active, so we trigger a
restart of the main systemd service.

nixos/modules/services/networking/firefox-syncserver.nix

@@ -32,6 +32,44 @@ let
     };
   };
   configFile = format.generate "syncstorage.toml" (lib.recursiveUpdate settings cfg.settings);
+  setupScript = pkgs.writeShellScript "firefox-syncserver-setup" ''
+        set -euo pipefail
+        shopt -s inherit_errexit
+
+        schema_configured() {
+          mysql ${cfg.database.name} -Ne 'SHOW TABLES' | grep -q services
+        }
+
+        update_config() {
+          mysql ${cfg.database.name} <<"EOF"
+            BEGIN;
+
+            INSERT INTO `services` (`id`, `service`, `pattern`)
+              VALUES (1, 'sync-1.5', '{node}/1.5/{uid}')
+              ON DUPLICATE KEY UPDATE service='sync-1.5', pattern='{node}/1.5/{uid}';
+            INSERT INTO `nodes` (`id`, `service`, `node`, `available`, `current_load`,
+                                 `capacity`, `downed`, `backoff`)
+              VALUES (1, 1, '${cfg.singleNode.url}', ${toString cfg.singleNode.capacity},
+              0, ${toString cfg.singleNode.capacity}, 0, 0)
+              ON DUPLICATE KEY UPDATE node = '${cfg.singleNode.url}', capacity=${toString cfg.singleNode.capacity};
+
+            COMMIT;
+        EOF
+        }
+
+
+        for (( try = 0; try < 60; try++ )); do
+          if ! schema_configured; then
+            sleep 2
+          else
+            update_config
+            exit 0
+          fi
+        done
+
+        echo "Single-node setup failed"
+        exit 1
+      '';
 in
 
 {
@@ -210,6 +248,7 @@ in
       wantedBy = [ "multi-user.target" ];
       requires = lib.mkIf dbIsLocal [ "mysql.service" ];
       after = lib.mkIf dbIsLocal [ "mysql.service" ];
+      restartTriggers = lib.optional cfg.singleNode.enable setupScript;
       environment.RUST_LOG = cfg.logLevel;
       serviceConfig = {
         User = defaultUser;
@@ -255,56 +294,7 @@ in
       requires = [ "firefox-syncserver.service" ] ++ lib.optional dbIsLocal "mysql.service";
       after = [ "firefox-syncserver.service" ] ++ lib.optional dbIsLocal "mysql.service";
       path = [ config.services.mysql.package ];
-      script = ''
+      serviceConfig.ExecStart = [ "${setupScript}" ];
-        set -euo pipefail
-        shopt -s inherit_errexit
-
-        schema_configured() {
-          mysql ${cfg.database.name} -Ne 'SHOW TABLES' | grep -q services
-        }
-
-        services_configured() {
-          [ 1 != $(mysql ${cfg.database.name} -Ne 'SELECT COUNT(*) < 1 FROM `services`') ]
-        }
-
-        create_services() {
-          mysql ${cfg.database.name} <<"EOF"
-            BEGIN;
-
-            INSERT INTO `services` (`id`, `service`, `pattern`)
-              VALUES (1, 'sync-1.5', '{node}/1.5/{uid}');
-            INSERT INTO `nodes` (`id`, `service`, `node`, `available`, `current_load`,
-                                 `capacity`, `downed`, `backoff`)
-              VALUES (1, 1, '${cfg.singleNode.url}', ${toString cfg.singleNode.capacity},
-                      0, ${toString cfg.singleNode.capacity}, 0, 0);
-
-            COMMIT;
-        EOF
-        }
-
-        update_nodes() {
-          mysql ${cfg.database.name} <<"EOF"
-            UPDATE `nodes`
-              SET `capacity` = ${toString cfg.singleNode.capacity}
-              WHERE `id` = 1;
-        EOF
-        }
-
-        for (( try = 0; try < 60; try++ )); do
-          if ! schema_configured; then
-            sleep 2
-          elif services_configured; then
-            update_nodes
-            exit 0
-          else
-            create_services
-            exit 0
-          fi
-        done
-
-        echo "Single-node setup failed"
-        exit 1
-      '';
     };
 
     services.nginx.virtualHosts = lib.mkIf cfg.singleNode.enableNginx {