mysql: fix replication tests (#17174)

Eliminate race condition in replication test
Remove replication configuration from standalone test
Improve mysql command syntax consistency

nixos/modules/services/databases/mysql.nix

···
                     # Set up the replication master
 
                     ( echo "use mysql;"
+                      echo "CREATE USER '${cfg.replication.masterUser}'@'${cfg.replication.slaveHost}' IDENTIFIED WITH mysql_native_password;"
+                      echo "SET PASSWORD FOR '${cfg.replication.masterUser}'@'${cfg.replication.slaveHost}' = PASSWORD('${cfg.replication.masterPassword}');"
                       echo "GRANT REPLICATION SLAVE ON *.* TO '${cfg.replication.masterUser}'@'${cfg.replication.slaveHost}';"
-                      echo "update user set Password=password('${cfg.replication.masterPassword}') where User='${cfg.replication.masterUser}';"
                     ) | ${mysql}/bin/mysql -u root -N
                   ''}
 

nixos/tests/mysql-replication.nix

···
         services.mysql.enable = true;
         services.mysql.package = pkgs.mysql;
         services.mysql.replication.role = "master";
+        services.mysql.replication.slaveHost = "%";
+        services.mysql.replication.masterUser = replicateUser;
+        services.mysql.replication.masterPassword = replicatePassword;
         services.mysql.initialDatabases = [ { name = "testdb"; schema = ./testdb.sql; } ];
-        services.mysql.initialScript = pkgs.writeText "initmysql"
-          ''
-            create user '${replicateUser}'@'%' identified by '${replicatePassword}';
-            grant replication slave on *.* to '${replicateUser}'@'%';
-          '';
         networking.firewall.allowedTCPPorts = [ 3306 ];
       };
 
···
   };
 
   testScript = ''
-    startAll;
-
+    $master->start;
     $master->waitForUnit("mysql");
-    $master->waitForUnit("mysql");
+    $slave1->start;
+    $slave2->start;
+    $slave1->waitForUnit("mysql");
     $slave2->waitForUnit("mysql");
     $slave2->sleep(100); # Hopefully this is long enough!!
     $slave2->succeed("echo 'use testdb; select * from tests' | mysql -u root -N | grep 4");

nixos/tests/mysql.nix

···
 
       {
         services.mysql.enable = true;
-        services.mysql.replication.role = "master";
         services.mysql.initialDatabases = [ { name = "testdb"; schema = ./testdb.sql; } ];
         services.mysql.package = pkgs.mysql;
       };