From 459a63f20a8634ca081f68df5ca793ff1885ad60 Mon Sep 17 00:00:00 2001
From: 6543 <6543@obermui.de>
Date: Mon, 30 Dec 2024 20:28:55 +0100
Subject: [PATCH 1/7] services.mysqlBackup: cleanup

---
 nixos/modules/services/backup/mysql-backup.nix | 9 +--------
 1 file changed, 1 insertion(+), 8 deletions(-)

diff --git a/nixos/modules/services/backup/mysql-backup.nix b/nixos/modules/services/backup/mysql-backup.nix
index b30579103699..56ec17917753 100644
--- a/nixos/modules/services/backup/mysql-backup.nix
+++ b/nixos/modules/services/backup/mysql-backup.nix
@@ -5,9 +5,6 @@
   ...
 }:
 let
-
-  inherit (pkgs) mariadb gzip;
-
   cfg = config.services.mysqlBackup;
   defaultUser = "mysqlbackup";
 
@@ -22,7 +19,7 @@ let
   '';
   backupDatabaseScript = db: ''
     dest="${cfg.location}/${db}.gz"
-    if ${mariadb}/bin/mysqldump ${lib.optionalString cfg.singleTransaction "--single-transaction"} ${db} | ${gzip}/bin/gzip -c ${cfg.gzipOptions} > $dest.tmp; then
+    if ${pkgs.mariadb}/bin/mysqldump ${lib.optionalString cfg.singleTransaction "--single-transaction"} ${db} | ${pkgs.gzip}/bin/gzip -c ${cfg.gzipOptions} > $dest.tmp; then
       mv $dest.tmp $dest
       echo "Backed up to $dest"
     else
@@ -33,12 +30,9 @@ let
   '';
 
 in
-
 {
   options = {
-
     services.mysqlBackup = {
-
       enable = lib.mkEnableOption "MySQL backups";
 
       calendar = lib.mkOption {
@@ -106,7 +100,6 @@ in
       {
         name = cfg.user;
         ensurePermissions =
-          with lib;
           let
             privs = "SELECT, SHOW VIEW, TRIGGER, LOCK TABLES";
             grant = db: lib.nameValuePair "${db}.*" privs;

From ec9d4c4ae6425d68a4d2b5749b506eddc6eabd3e Mon Sep 17 00:00:00 2001
From: 6543 <6543@obermui.de>
Date: Mon, 30 Dec 2024 20:33:18 +0100
Subject: [PATCH 2/7] services.mysqlBackup: add option to change compression
 tool

---
 .../modules/services/backup/mysql-backup.nix  | 91 ++++++++++++++++++-
 1 file changed, 86 insertions(+), 5 deletions(-)

diff --git a/nixos/modules/services/backup/mysql-backup.nix b/nixos/modules/services/backup/mysql-backup.nix
index 56ec17917753..c4264120f997 100644
--- a/nixos/modules/services/backup/mysql-backup.nix
+++ b/nixos/modules/services/backup/mysql-backup.nix
@@ -8,6 +8,41 @@ let
   cfg = config.services.mysqlBackup;
   defaultUser = "mysqlbackup";
 
+  compressionPkg =
+    {
+      gzip = pkgs.gzip;
+      xz = pkgs.xz;
+      zstd = pkgs.zstd;
+    }
+    .${cfg.compressionAlg};
+
+  fileExt =
+    {
+      gzip = ".gz";
+      zstd = ".zst";
+      xz = ".xz";
+    }
+    .${cfg.compressionAlg};
+
+  validCompressionLevels = {
+    zstd = range: 1 <= range && range <= 19;
+    xz = range: 0 <= range && range <= 9;
+    gzip = range: 1 <= range && range <= 9;
+  };
+
+  compressionCmd =
+    let
+      compressionLevelFlag = lib.optionalString (cfg.compressionLevel != null) (
+        "-" + toString cfg.compressionLevel
+      );
+    in
+    {
+      gzip = "${pkgs.gzip}/bin/gzip -c ${cfg.gzipOptions} ${compressionLevelFlag}";
+      xz = "${pkgs.xz}/bin/xz -z -c ${compressionLevelFlag} -";
+      zstd = "${pkgs.zstd}/bin/zstd ${compressionLevelFlag} -";
+    }
+    .${cfg.compressionAlg};
+
   backupScript = ''
     set -o pipefail
     failed=""
@@ -17,9 +52,10 @@ let
       exit 1
     fi
   '';
+
   backupDatabaseScript = db: ''
-    dest="${cfg.location}/${db}.gz"
-    if ${pkgs.mariadb}/bin/mysqldump ${lib.optionalString cfg.singleTransaction "--single-transaction"} ${db} | ${pkgs.gzip}/bin/gzip -c ${cfg.gzipOptions} > $dest.tmp; then
+    dest="${cfg.location}/${db}${fileExt}"
+    if ${pkgs.mariadb}/bin/mysqldump ${lib.optionalString cfg.singleTransaction "--single-transaction"} ${db} | ${compressionCmd} > $dest.tmp; then
       mv $dest.tmp $dest
       echo "Backed up to $dest"
     else
@@ -43,6 +79,29 @@ in
         '';
       };
 
+      compressionAlg = lib.mkOption {
+        type = lib.types.enum [
+          "gzip"
+          "zstd"
+          "xz"
+        ];
+        default = "gzip";
+        description = ''
+          Compression algorithm to use for database dumps.
+        '';
+      };
+
+      compressionLevel = lib.mkOption {
+        type = lib.types.nullOr lib.types.int;
+        default = null;
+        description = ''
+          Compression level to use for gzip, zstd or xz.
+          For gzip: 1-9 (note: if compression level is also specified in gzipOptions, the gzipOptions value will be overwritten)
+          For zstd: 1-19
+          For xz: 0-9
+        '';
+      };
+
       user = lib.mkOption {
         type = lib.types.str;
         default = defaultUser;
@@ -63,7 +122,7 @@ in
         type = lib.types.path;
         default = "/var/backup/mysql";
         description = ''
-          Location to put the gzipped MySQL database dumps.
+          Location to put the compressed MySQL database dumps.
         '';
       };
 
@@ -80,13 +139,32 @@ in
         type = lib.types.str;
         description = ''
           Command line options to use when invoking `gzip`.
+          Only used when compression is set to "gzip".
+          If compression level is specified both here and in compressionLevel, the compressionLevel value will take precedence.
         '';
       };
     };
-
   };
 
   config = lib.mkIf cfg.enable {
+    # assert config to be correct
+    assertions = [
+      {
+        assertion =
+          cfg.compressionLevel == null || validCompressionLevels.${cfg.compressionAlg} cfg.compressionLevel;
+        message =
+          let
+            rangeMsg = {
+              "zstd" = "zstd compression level must be between 1 and 19";
+              "xz" = "xz compression level must be between 0 and 9";
+              "gzip" = "gzip compression level must be between 1 and 9";
+            };
+          in
+          rangeMsg.${cfg.compressionAlg};
+      }
+    ];
+
+    # ensure unix user to be used to perform backup exist.
     users.users = lib.optionalAttrs (cfg.user == defaultUser) {
       ${defaultUser} = {
         isSystemUser = true;
@@ -96,6 +174,10 @@ in
       };
     };
 
+    # add the compression tool to the system environment.
+    environment.systemPackages = [ compressionPkg ];
+
+    # ensure database user to be used to perform backup exist.
     services.mysql.ensureUsers = [
       {
         name = cfg.user;
@@ -132,5 +214,4 @@ in
       ];
     };
   };
-
 }

From 8b4703426c0e129ca8425fbf5e396158ccd4b8fe Mon Sep 17 00:00:00 2001
From: 6543 <6543@obermui.de>
Date: Mon, 6 Jan 2025 15:42:16 +0100
Subject: [PATCH 3/7] services.mysqlBackup: add myselfe as maintainer

---
 nixos/modules/services/backup/mysql-backup.nix | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/nixos/modules/services/backup/mysql-backup.nix b/nixos/modules/services/backup/mysql-backup.nix
index c4264120f997..ef6e94ddd1d5 100644
--- a/nixos/modules/services/backup/mysql-backup.nix
+++ b/nixos/modules/services/backup/mysql-backup.nix
@@ -214,4 +214,6 @@ in
       ];
     };
   };
+
+  meta.maintainers = [ lib.maintainers._6543 ];
 }

From 085ebf0376df870bc410d6441647b511946f959e Mon Sep 17 00:00:00 2001
From: 6543 <6543@obermui.de>
Date: Wed, 8 Jan 2025 14:41:02 +0100
Subject: [PATCH 4/7] services.mysqlBackup: apply suggested refactoring

---
 .../modules/services/backup/mysql-backup.nix  | 94 ++++++++-----------
 1 file changed, 40 insertions(+), 54 deletions(-)

diff --git a/nixos/modules/services/backup/mysql-backup.nix b/nixos/modules/services/backup/mysql-backup.nix
index ef6e94ddd1d5..9819c5bda443 100644
--- a/nixos/modules/services/backup/mysql-backup.nix
+++ b/nixos/modules/services/backup/mysql-backup.nix
@@ -8,40 +8,36 @@ let
   cfg = config.services.mysqlBackup;
   defaultUser = "mysqlbackup";
 
-  compressionPkg =
-    {
-      gzip = pkgs.gzip;
-      xz = pkgs.xz;
-      zstd = pkgs.zstd;
-    }
-    .${cfg.compressionAlg};
-
-  fileExt =
-    {
-      gzip = ".gz";
-      zstd = ".zst";
-      xz = ".xz";
-    }
-    .${cfg.compressionAlg};
-
-  validCompressionLevels = {
-    zstd = range: 1 <= range && range <= 19;
-    xz = range: 0 <= range && range <= 9;
-    gzip = range: 1 <= range && range <= 9;
+  compressionAlgs = {
+    gzip = rec {
+      pkg = pkgs.gzip;
+      ext = ".gz";
+      minLevel = 1;
+      maxLevel = 9;
+      cmd = compressionLevelFlag: "${pkg}/bin/gzip -c ${cfg.gzipOptions} ${compressionLevelFlag}";
+    };
+    xz = rec {
+      pkg = pkgs.xz;
+      ext = ".xz";
+      minLevel = 0;
+      maxLevel = 9;
+      cmd = compressionLevelFlag: "${pkg}/bin/xz -z -c ${compressionLevelFlag} -";
+    };
+    zstd = rec {
+      pkg = pkgs.zstd;
+      ext = ".zst";
+      minLevel = 1;
+      maxLevel = 19;
+      cmd = compressionLevelFlag: "${pkg}/bin/zstd ${compressionLevelFlag} -";
+    };
   };
 
-  compressionCmd =
-    let
-      compressionLevelFlag = lib.optionalString (cfg.compressionLevel != null) (
-        "-" + toString cfg.compressionLevel
-      );
-    in
-    {
-      gzip = "${pkgs.gzip}/bin/gzip -c ${cfg.gzipOptions} ${compressionLevelFlag}";
-      xz = "${pkgs.xz}/bin/xz -z -c ${compressionLevelFlag} -";
-      zstd = "${pkgs.zstd}/bin/zstd ${compressionLevelFlag} -";
-    }
-    .${cfg.compressionAlg};
+  compressionLevelFlag = lib.optionalString (cfg.compressionLevel != null) (
+    "-" + toString cfg.compressionLevel
+  );
+
+  selectedAlg = compressionAlgs.${cfg.compressionAlg};
+  compressionCmd = selectedAlg.cmd compressionLevelFlag;
 
   backupScript = ''
     set -o pipefail
@@ -54,7 +50,7 @@ let
   '';
 
   backupDatabaseScript = db: ''
-    dest="${cfg.location}/${db}${fileExt}"
+    dest="${cfg.location}/${db}${selectedAlg.ext}"
     if ${pkgs.mariadb}/bin/mysqldump ${lib.optionalString cfg.singleTransaction "--single-transaction"} ${db} | ${compressionCmd} > $dest.tmp; then
       mv $dest.tmp $dest
       echo "Backed up to $dest"
@@ -80,11 +76,7 @@ in
       };
 
       compressionAlg = lib.mkOption {
-        type = lib.types.enum [
-          "gzip"
-          "zstd"
-          "xz"
-        ];
+        type = lib.types.enum (lib.attrNames compressionAlgs);
         default = "gzip";
         description = ''
           Compression algorithm to use for database dumps.
@@ -95,10 +87,13 @@ in
         type = lib.types.nullOr lib.types.int;
         default = null;
         description = ''
-          Compression level to use for gzip, zstd or xz.
-          For gzip: 1-9 (note: if compression level is also specified in gzipOptions, the gzipOptions value will be overwritten)
-          For zstd: 1-19
-          For xz: 0-9
+          Compression level to use for ${lib.concatStringsSep ", " (lib.init (lib.attrNames compressionAlgs))} or ${lib.last (lib.attrNames compressionAlgs)}.
+          ${lib.concatStringsSep "\n" (
+            lib.mapAttrsToList (
+              name: algo: "  For ${name}: ${toString algo.minLevel}-${toString algo.maxLevel}"
+            ) compressionAlgs
+          )}
+          (note: if compression level is also specified in gzipOptions, the gzipOptions value will be overwritten)
         '';
       };
 
@@ -150,17 +145,8 @@ in
     # assert config to be correct
     assertions = [
       {
-        assertion =
-          cfg.compressionLevel == null || validCompressionLevels.${cfg.compressionAlg} cfg.compressionLevel;
-        message =
-          let
-            rangeMsg = {
-              "zstd" = "zstd compression level must be between 1 and 19";
-              "xz" = "xz compression level must be between 0 and 9";
-              "gzip" = "gzip compression level must be between 1 and 9";
-            };
-          in
-          rangeMsg.${cfg.compressionAlg};
+        assertion = cfg.compressionLevel == null || selectedAlg.minLevel <= cfg.compressionLevel && cfg.compressionLevel <= selectedAlg.maxLevel;
+        message = "${cfg.compressionAlg} compression level must be between ${toString selectedAlg.minLevel} and ${toString selectedAlg.maxLevel}";
       }
     ];
 
@@ -175,7 +161,7 @@ in
     };
 
     # add the compression tool to the system environment.
-    environment.systemPackages = [ compressionPkg ];
+    environment.systemPackages = [ selectedAlg.pkg ];
 
     # ensure database user to be used to perform backup exist.
     services.mysql.ensureUsers = [

From 710b189b1477656abc6fed7172e12a9a865cce22 Mon Sep 17 00:00:00 2001
From: 6543 <6543@obermui.de>
Date: Sun, 12 Jan 2025 19:46:45 +0100
Subject: [PATCH 5/7] services.mysqlBackup: apply markdown to description

Co-authored-by: Silvan Mosberger <github@infinisil.com>
---
 nixos/modules/services/backup/mysql-backup.nix | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/nixos/modules/services/backup/mysql-backup.nix b/nixos/modules/services/backup/mysql-backup.nix
index 9819c5bda443..494871acb6d1 100644
--- a/nixos/modules/services/backup/mysql-backup.nix
+++ b/nixos/modules/services/backup/mysql-backup.nix
@@ -90,10 +90,13 @@ in
           Compression level to use for ${lib.concatStringsSep ", " (lib.init (lib.attrNames compressionAlgs))} or ${lib.last (lib.attrNames compressionAlgs)}.
           ${lib.concatStringsSep "\n" (
             lib.mapAttrsToList (
-              name: algo: "  For ${name}: ${toString algo.minLevel}-${toString algo.maxLevel}"
+              name: algo: "- For ${name}: ${toString algo.minLevel}-${toString algo.maxLevel}"
             ) compressionAlgs
           )}
-          (note: if compression level is also specified in gzipOptions, the gzipOptions value will be overwritten)
+          
+          :::{.note}
+          If compression level is also specified in gzipOptions, the gzipOptions value will be overwritten
+          :::
         '';
       };
 

From 233db85960bc6037b25c11af84c278a5eb3812b4 Mon Sep 17 00:00:00 2001
From: 6543 <6543@obermui.de>
Date: Sun, 12 Jan 2025 19:58:18 +0100
Subject: [PATCH 6/7] ci/OWNERS: add myselfe as maintainer for mysql-backup

---
 ci/OWNERS | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/ci/OWNERS b/ci/OWNERS
index bf6e070d80e4..53bc85394e46 100644
--- a/ci/OWNERS
+++ b/ci/OWNERS
@@ -251,6 +251,9 @@ pkgs/development/python-modules/buildcatrust/ @ajs124 @lukegb @mweinelt
 /nixos/modules/services/databases/postgresql.nix @NixOS/postgres
 /nixos/tests/postgresql @NixOS/postgres
 
+# MySQL/MariaDB and related stuff
+/nixos/modules/services/backup/mysql-backup.nix @6543
+
 # Hardened profile & related modules
 /nixos/modules/profiles/hardened.nix                       @joachifm
 /nixos/modules/security/lock-kernel-modules.nix            @joachifm

From 917be2fef67d5bf8fa0567a5f3e192b968ae1cd7 Mon Sep 17 00:00:00 2001
From: 6543 <6543@obermui.de>
Date: Sun, 12 Jan 2025 20:00:54 +0100
Subject: [PATCH 7/7] services.mysqlBackup: nixfmt

---
 nixos/modules/services/backup/mysql-backup.nix | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/nixos/modules/services/backup/mysql-backup.nix b/nixos/modules/services/backup/mysql-backup.nix
index 494871acb6d1..33dc1c35ebeb 100644
--- a/nixos/modules/services/backup/mysql-backup.nix
+++ b/nixos/modules/services/backup/mysql-backup.nix
@@ -93,7 +93,7 @@ in
               name: algo: "- For ${name}: ${toString algo.minLevel}-${toString algo.maxLevel}"
             ) compressionAlgs
           )}
-          
+
           :::{.note}
           If compression level is also specified in gzipOptions, the gzipOptions value will be overwritten
           :::
@@ -148,7 +148,9 @@ in
     # assert config to be correct
     assertions = [
       {
-        assertion = cfg.compressionLevel == null || selectedAlg.minLevel <= cfg.compressionLevel && cfg.compressionLevel <= selectedAlg.maxLevel;
+        assertion =
+          cfg.compressionLevel == null
+          || selectedAlg.minLevel <= cfg.compressionLevel && cfg.compressionLevel <= selectedAlg.maxLevel;
         message = "${cfg.compressionAlg} compression level must be between ${toString selectedAlg.minLevel} and ${toString selectedAlg.maxLevel}";
       }
     ];