Improve printing

Reviewed-on: #2

README.md

@@ -2,3 +2,20 @@
 
 Small NixOS module to do backups to my NAS.
 
+## Usage example
+
+```nix
+# Example uses sops to store repo password
+sops.secrets."backup_helper_secret" = { };
+backup-helper = {
+  enable = true;
+  password-file = "/run/secrets/backup_helper_secret";
+  # Dirs to backup
+  backup-dirs = [
+    "/var/lib/important-data"
+    "/home/user/stuff"
+  ];
+};
+```
+
+See [this](https://git.t-juice.club/torjus/backup-helper/src/commit/e84295ad5951fe3eb97113a94c16fbed412734e5/backup.nix#L42-L71) for all options and defaults.

backup.nix

@@ -11,25 +11,7 @@ let
     runtimeInputs = [
       pkgs.restic
     ];
-    text = ''
-      if [ -z "$BACKUP_HELPER_DIRS"  ]; then
-        echo "BACKUP_HELPER_DIRS is not set"
-        exit 1;
-      fi
-      exit_code=0;
-      for i in ''${BACKUP_HELPER_DIRS//,/ }; do
-        echo "Starting backup of $i";
-        if ! output=$(restic backup "$i"); then
-          exit_code=1;
-          echo "Backup of $i failed with exit code $?:"
-          echo "$output"
-        else
-          echo "Backup of $i successful:"
-          echo "$output"
-        fi
-      done
-      exit "$exit_code";
-    '';
+    text = (builtins.readFile ./backup.sh);
   };
 in
 {
@@ -45,6 +27,11 @@ in
       default = [ ];
       description = "Directories to be backed up.";
     };
+    backup-commands = lib.mkOption {
+      type = lib.types.listOf lib.types.str;
+      default = [ ];
+      description = "Backup the stdout of commands. Format strings like key:command";
+    };
     schedule = lib.mkOption {
       type = lib.types.str;
       default = "*-*-* 00:00:00";
@@ -60,6 +47,11 @@ in
       default = 0;
       description = "Randomized delay in seconds to spread out backups.";
     };
+    forget = lib.mkOption {
+      type = lib.types.bool;
+      default = true;
+      description = "Run restic forget after backup.";
+    };
   };
   config = lib.mkIf cfg.enable {
     systemd.services."backup-helper" = {
@@ -69,9 +61,13 @@ in
         {
           RESTIC_REPOSITORY = cfg.restic-repository;
           BACKUP_HELPER_DIRS = lib.strings.concatStringsSep "," cfg.backup-dirs;
+          BACKUP_FORGET = if cfg.forget then "1" else "0";
         }
         // lib.attrsets.optionalAttrs (builtins.hasAttr "password-file" cfg) {
           RESTIC_PASSWORD_FILE = cfg.password-file;
+        }
+        // lib.attrsets.optionalAttrs (cfg.backup-commands != [ ]) {
+          BACKUP_HELPER_COMMANDS = lib.strings.concatStringsSep ";" cfg.backup-commands;
         };
       serviceConfig = {
         Type = "oneshot";

backup.sh

@@ -0,0 +1,51 @@
+#!/usr/bin/env bash
+
+# If neither of BACKUP_HELPER_DIRS and BACKUP_HELPER_COMMANDS not set. Exit
+if [ -z "$BACKUP_HELPER_DIRS" ] && [ -z "$BACKUP_HELPER_COMMANDS" ]; then
+  echo "BACKUP_HELPER_DIRS is not set"
+  exit 1;
+fi
+exit_code=0;
+
+# Backup directories
+if [ -n "$BACKUP_HELPER_DIRS" ]; then
+  for i in ${BACKUP_HELPER_DIRS//,/ }; do
+    echo "Starting backup of $i";
+    if ! output=$(restic backup "$i"); then
+      exit_code=1;
+      echo "Backup of $i failed with exit code $?:"
+      echo "$output"
+    else
+      echo "Backup of $i successful:"
+      echo "$output"
+    fi
+  done
+fi
+
+# Backup command outputs
+if [ -n "$BACKUP_HELPER_COMMANDS" ]; then
+  IFS=";" read -r -a pairs <<< "$BACKUP_HELPER_COMMANDS"
+
+  for pair in "${pairs[@]}"; do
+      IFS=":" read -r key value <<< "$pair"
+
+      # Split value into array of command args
+      IFS=' ' read -r -a cmd_parts <<< "$value"
+      if ! output=$(restic backup --stdin-filename "$key" --stdin-from-command -- "${cmd_parts[@]}"); then
+        exit_code=1;
+        echo "Backup of $key failed with exit code $?:"
+        echo "$output"
+      else
+        echo "Backup of $key successful:"
+        echo "$output"
+      fi
+        
+  done
+fi
+
+if [ "$BACKUP_FORGET" -eq 1 ]; then
+  echo "Removing old backups"
+  output=$(restic forget -d 7 -w 4 -m 6 --keep-within 1d --prune)
+  echo "$output"
+fi
+exit "$exit_code"

flake.nix

@@ -3,7 +3,8 @@
 
   inputs.nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
 
-  outputs = { self, nixpkgs }:
+  outputs =
+    { self, nixpkgs }:
     let
       allSystems = [
         "x86_64-linux"
@@ -11,24 +12,31 @@
         "x86_64-darwin"
         "aarch64-darwin"
       ];
-      forAllSystems = f: nixpkgs.lib.genAttrs allSystems (system: f {
+      forAllSystems =
+        f:
+        nixpkgs.lib.genAttrs allSystems (
+          system:
+          f {
             pkgs = import nixpkgs { inherit system; };
-      });
+          }
+        );
     in
     {
       nixosModules.backup-helper = import ./backup.nix;
       nixosModules.default = self.nixosModules.backup-helper;
 
-      devShells = forAllSystems ({ pkgs }: {
+      devShells = forAllSystems (
+        { pkgs }:
+        {
           default = pkgs.mkShell {
-          packages = with pkgs;
-            [
+            packages = with pkgs; [
               restic
               bash
               jq
               curl
             ];
           };
-      });
+        }
+      );
     };
 }