2 files changed, 28 insertions, 4 deletions
diff --git a/nixpkgs/nixos/modules/services/databases/mysql.nix b/nixpkgs/nixos/modules/services/databases/mysql.nix
index 7d0a3f9afc48..cf105daeb04e 100644
--- a/nixpkgs/nixos/modules/services/databases/mysql.nix
+++ b/nixpkgs/nixos/modules/services/databases/mysql.nix
@@ -375,6 +375,18 @@ in
           fi
         '';
 
+        script = ''
+          # https://mariadb.com/kb/en/getting-started-with-mariadb-galera-cluster/#systemd-and-galera-recovery
+          if test -n "''${_WSREP_START_POSITION}"; then
+            if test -e "${cfg.package}/bin/galera_recovery"; then
+              VAR=$(cd ${cfg.package}/bin/..; ${cfg.package}/bin/galera_recovery); [[ $? -eq 0 ]] && export _WSREP_START_POSITION=$VAR || exit 1
+            fi
+          fi
+
+          # The last two environment variables are used for starting Galera clusters
+          exec ${cfg.package}/bin/mysqld --defaults-file=/etc/my.cnf ${mysqldOptions} $_WSREP_NEW_CLUSTER $_WSREP_START_POSITION
+        '';
+
         postStart = let
           # The super user account to use on *first* run of MySQL server
           superUser = if isMariaDB then cfg.user else "root";
@@ -481,8 +493,7 @@ in
           Type = if hasNotify then "notify" else "simple";
           Restart = "on-abort";
           RestartSec = "5s";
-          # The last two environment variables are used for starting Galera clusters
-          ExecStart = "${cfg.package}/bin/mysqld --defaults-file=/etc/my.cnf ${mysqldOptions} $_WSREP_NEW_CLUSTER $_WSREP_START_POSITION";
+
           # User and group
           User = cfg.user;
           Group = cfg.group;
diff --git a/nixpkgs/nixos/modules/services/databases/postgresql.nix b/nixpkgs/nixos/modules/services/databases/postgresql.nix
index f582b0592774..900185fbbdf7 100644
--- a/nixpkgs/nixos/modules/services/databases/postgresql.nix
+++ b/nixpkgs/nixos/modules/services/databases/postgresql.nix
@@ -18,7 +18,12 @@ let
     else toString value;
 
   # The main PostgreSQL configuration file.
-  configFile = pkgs.writeText "postgresql.conf" (concatStringsSep "\n" (mapAttrsToList (n: v: "${n} = ${toStr v}") cfg.settings));
+  configFile = pkgs.writeTextDir "postgresql.conf" (concatStringsSep "\n" (mapAttrsToList (n: v: "${n} = ${toStr v}") cfg.settings));
+
+  configFileCheck = pkgs.runCommand "postgresql-configfile-check" {} ''
+    ${cfg.package}/bin/postgres -D${configFile} -C config_file >/dev/null
+    touch $out
+  '';
 
   groupAccessAvailable = versionAtLeast postgresql.version "11.0";
 
@@ -53,6 +58,12 @@ in
         '';
       };
 
+      checkConfig = mkOption {
+        type = types.bool;
+        default = true;
+        description = "Check the syntax of the configuration file at compile time";
+      };
+
       dataDir = mkOption {
         type = types.path;
         defaultText = "/var/lib/postgresql/\${config.services.postgresql.package.psqlSchema}";
@@ -314,6 +325,8 @@ in
      "/share/postgresql"
     ];
 
+    system.extraDependencies = lib.optional (cfg.checkConfig && pkgs.stdenv.hostPlatform == pkgs.stdenv.buildPlatform) configFileCheck;
+
     systemd.services.postgresql =
       { description = "PostgreSQL Server";
 
@@ -337,7 +350,7 @@ in
               touch "${cfg.dataDir}/.first_startup"
             fi
 
-            ln -sfn "${configFile}" "${cfg.dataDir}/postgresql.conf"
+            ln -sfn "${configFile}/postgresql.conf" "${cfg.dataDir}/postgresql.conf"
             ${optionalString (cfg.recoveryConfig != null) ''
               ln -sfn "${pkgs.writeText "recovery.conf" cfg.recoveryConfig}" \
                 "${cfg.dataDir}/recovery.conf"