Add postgresql replication for backup-2

1 files changed, 21 insertions, 0 deletions

diff --git a/modules/private/databases/postgresql.nix b/modules/private/databases/postgresql.nix
index 6d1901d..1932a82 100644
--- a/modules/private/databases/postgresql.nix
+++ b/modules/private/databases/postgresql.nix
@@ -121,6 +121,27 @@ in {
       SupplementaryGroups = "keys";
       RuntimeDirectory = cfg.systemdRuntimeDirectory;
     };
+    systemd.services.postgresql.postStart = lib.mkAfter ''
+      # This line is already defined in 19.09
+      PSQL="${pkgs.sudo}/bin/sudo -u postgres psql --port=5432"
+
+      ${builtins.concatStringsSep "\n" (lib.mapAttrsToList (role: _: ''
+        $PSQL -tAc "SELECT 1 FROM pg_roles WHERE rolname='${role}'" \
+            | grep -q 1 \
+            || $PSQL -tAc 'CREATE USER "${role}" WITH REPLICATION'
+        '') cfg.replicationHosts)}
+
+      ${builtins.concatStringsSep "\n" (lib.mapAttrsToList (role: _:
+        let
+          sname = builtins.replaceStrings ["-"] ["_"] role;
+        in
+        ''
+        $PSQL -tAc "SELECT 1 FROM pg_replication_slots WHERE slot_name='${sname}'" \
+              | grep -q 1 \
+              || $PSQL -tAc "SELECT * FROM pg_create_physical_replication_slot('${sname}')"
+        '') cfg.replicationHosts)}
+      '';
+
     services.postgresql = {
       enable = true;
       package = cfg.package;