fix(nix): support configured database credentials in maintenance tools

Author: Bolyki György

lib/teslamate/log.ex

@@ -240,6 +240,13 @@ defmodule TeslaMate.Log do
     |> Repo.insert()
   end
 
+  def delete_drive(id) when is_integer(id) do
+    case Repo.get(Drive, id) do
+      nil -> :not_found
+      drive -> delete(drive)
+    end
+  end
+
   def close_drive(%Drive{id: id} = drive, opts \\ []) do
     drive = Repo.preload(drive, [:car])
 
@@ -407,6 +414,13 @@ defmodule TeslaMate.Log do
     |> Repo.update()
   end
 
+  def delete_charging_process(id) when is_integer(id) do
+    case Repo.get(ChargingProcess, id) do
+      nil -> :not_found
+      charging_process -> delete(charging_process)
+    end
+  end
+
   def start_charging_process(%Car{id: id}, %{latitude: _, longitude: _} = attrs, opts \\ []) do
     lookup_address = Keyword.get(opts, :lookup_address, true)
     position = Map.put(attrs, :car_id, id)
@@ -708,4 +722,11 @@ defmodule TeslaMate.Log do
     |> Update.changeset(%{start_date: date, end_date: date, version: version})
     |> Repo.insert()
   end
+
+  defp delete(struct) do
+    case Repo.delete(struct) do
+      {:ok, _struct} -> :ok
+      {:error, _changeset} = error -> error
+    end
+  end
 end

nix/backup_and_restore.nix

@@ -1,39 +1,118 @@
 {
   stdenv,
   lib,
-  pkgs,
+  coreutils,
+  gnused,
+  postgresql,
+  systemd,
   writeShellScript,
   databaseUser,
   databaseName,
+  databaseHost,
+  databasePort,
+  environmentFilePath,
   ...
 }:
 let
+  pgDump = lib.getExe' postgresql "pg_dump";
+  psql = lib.getExe' postgresql "psql";
+  sed = lib.getExe gnused;
+  systemctl = lib.getExe' systemd "systemctl";
+  tail = lib.getExe' coreutils "tail";
+  databaseArgs = lib.escapeShellArgs [
+    "--host=${databaseHost}"
+    "--port=${toString databasePort}"
+    "--username=${databaseUser}"
+    "--dbname=${databaseName}"
+    "--no-password"
+  ];
+  loadDatabasePassword = ''
+    load_database_password() {
+      if [ ! -r ${lib.escapeShellArg environmentFilePath} ]; then
+        printf '%s\n' ${lib.escapeShellArg "Environment file ${environmentFilePath} not found or not readable."} >&2
+        return 1
+      fi
+
+      database_password="$(
+        ${sed} -n 's/^DATABASE_PASS=//p' ${lib.escapeShellArg environmentFilePath} |
+          ${tail} -n 1
+      )"
+
+      case "$database_password" in
+        \"*\")
+          database_password="''${database_password#\"}"
+          database_password="''${database_password%\"}"
+          ;;
+      esac
+
+      if [ -z "$database_password" ]; then
+        printf '%s\n' ${lib.escapeShellArg "DATABASE_PASS must be set in ${environmentFilePath} (services.teslamate.secretsFile)."} >&2
+        return 1
+      fi
+    }
+
+    run_with_database_password() {
+      PGPASSWORD="$database_password" "$@"
+    }
+  '';
   backup = writeShellScript "teslamate-backup" ''
     set -euo pipefail
-    : ''${1?' Please specify a file to save backup'}
-    sudo -u teslamate pg_dump -U ${databaseUser} ${databaseName} > "$1"
+    : "''${1:?'Please specify a file to save backup'}"
+
+    ${loadDatabasePassword}
+    load_database_password
+    run_with_database_password ${pgDump} ${databaseArgs} > "$1"
   '';
   restore = writeShellScript "teslamate-restore" ''
     set -euo pipefail
-    : ''${1?' Please specify a file to restore from'}
+    : "''${1:?'Please specify a file to restore from'}"
+
+    if [ ! -f "$1" ]; then
+      printf 'Restore file %q does not exist, is not a regular file, or is not readable.\n' "$1" >&2
+      exit 1
+    fi
+    if ! exec 3< "$1"; then
+      printf 'Restore file %q does not exist, is not a regular file, or is not readable.\n' "$1" >&2
+      exit 1
+    fi
 
-    # Stop the teslamate service to avoid write conflicts
-    systemctl stop teslamate.service
+    ${loadDatabasePassword}
+    load_database_password
+
+    restart_teslamate() {
+      original_status="$?"
+      trap - EXIT
+
+      if ${systemctl} start teslamate.service 3<&-; then
+        restart_status=0
+      else
+        restart_status="$?"
+      fi
+
+      if [ "$original_status" -ne 0 ]; then
+        exit "$original_status"
+      fi
+
+      exit "$restart_status"
+    }
+
+    # Restart TeslaMate on every exit after this point. If reset or restore
+    # fails, preserve that original status even when restarting also fails.
+    trap restart_teslamate EXIT
+
+    ${systemctl} stop teslamate.service 3<&-
 
     # Drop existing data and reinitialize
-    sudo -u teslamate psql -U ${databaseUser} -d ${databaseName} << .
-      DROP SCHEMA IF EXISTS public cascade;
-      DROP SCHEMA IF EXISTS private CASCADE;
-      CREATE SCHEMA public;
-      CREATE EXTENSION cube WITH SCHEMA public;
-      CREATE EXTENSION earthdistance WITH SCHEMA public;
-    .
+    run_with_database_password ${psql} ${databaseArgs} --set=ON_ERROR_STOP=1 <<'SQL'
+    DROP SCHEMA IF EXISTS public CASCADE;
+    DROP SCHEMA IF EXISTS private CASCADE;
+    CREATE SCHEMA public;
+    CREATE EXTENSION cube WITH SCHEMA public;
+    CREATE EXTENSION earthdistance WITH SCHEMA public;
+    SQL
 
     # Restore
-    sudo -u teslamate psql -U ${databaseUser} -d ${databaseName} < "$1"
-
-    # Restart the teslamate container
-    systemctl start teslamate.service
+    run_with_database_password ${psql} ${databaseArgs} --set=ON_ERROR_STOP=1 <&3
   '';
 in
 stdenv.mkDerivation {