Fix nix module logging and storage formatting

nix/modules/darwin.nix

@@ -25,10 +25,13 @@
     if cfg.darwin.paths.blocksRoot != null
     then cfg.darwin.paths.blocksRoot
     else "${stateDir}/blocks";
+  fileLoggingEnabled = cfg.configSchema.logTarget == "file" || cfg.configSchema.logTarget == "both";
   logsPath =
     if cfg.darwin.paths.logsDir != null
     then cfg.darwin.paths.logsDir
-    else defaultLogsPath;
+    else if fileLoggingEnabled
+    then defaultLogsPath
+    else "${stateDir}/logs";
   configSource = shared.mkConfigToml {
     inherit cfg;
     inherit accountsPath;
@@ -103,14 +106,10 @@ in {
   ];
 
   config = lib.mkIf cfg.enable {
-    assertions = [
-      {
-        assertion = !(cfg.configFile != null && cfg.environmentFile != null);
-        message = "services.mithril.configFile and services.mithril.environmentFile cannot both be set.";
-      }
-    ];
     warnings =
-      lib.optional (!darwinExternalDiskUsed)
+      lib.optional (cfg.configFile != null && cfg.environmentFile != null)
+      (builtins.throw "services.mithril.configFile and services.mithril.environmentFile cannot both be set.")
+      ++ lib.optional (!darwinExternalDiskUsed)
       "Mithril on macOS writes heavily; use external storage (e.g. /Volumes/...) via services.mithril.darwin.paths.* or services.mithril.configSchema.storage* to reduce SSD wear.";
 
     services.mithril.configFile = lib.mkForce configFile;

nix/modules/home-manager/service.nix

@@ -20,22 +20,28 @@
     if pkgs.stdenv.isDarwin && cfg.darwin.paths.blocksRoot != null
     then cfg.darwin.paths.blocksRoot
     else "${stateDir}/blocks";
+  fileLoggingEnabled = cfg.configSchema.logTarget == "file" || cfg.configSchema.logTarget == "both";
   logsPath =
-    if pkgs.stdenv.isDarwin && cfg.darwin.paths.logsDir != null
+    if !fileLoggingEnabled
+    then null
+    else if pkgs.stdenv.isDarwin && cfg.darwin.paths.logsDir != null
     then cfg.darwin.paths.logsDir
     else cfg.configSchema.storageLogs;
   shared = import ../shared/lib.nix {inherit lib pkgs;};
   configTemplate = shared.mkConfigTomlTemplate {
     inherit cfg;
     accountsPath = "@STATE_DIRECTORY@/accounts";
     blocksRoot = "@STATE_DIRECTORY@/blocks";
-    logsPath = "@LOGS_DIRECTORY@";
+    logsPath =
+      if fileLoggingEnabled
+      then "@LOGS_DIRECTORY@"
+      else "@STATE_DIRECTORY@/logs";
   };
   configInitScript = pkgs.writeShellScript "mithril-generate-config-user" ''
     set -euo pipefail
     config_dir="$CONFIGURATION_DIRECTORY"
     state_dir="$STATE_DIRECTORY"
-    logs_dir="$LOGS_DIRECTORY"
+    logs_dir="''${LOGS_DIRECTORY:-}"
     runtime_dir="$RUNTIME_DIRECTORY"
     mkdir -p "$config_dir"
     mkdir -p "$runtime_dir"
@@ -132,12 +138,9 @@ in {
   config = lib.mkIf cfg.enable (
     lib.mkMerge [
       {
-        assertions = [
-          {
-            assertion = !(cfg.configFile != null && cfg.environmentFile != null);
-            message = "services.mithril.configFile and services.mithril.environmentFile cannot both be set.";
-          }
-        ];
+        warnings =
+          lib.optional (cfg.configFile != null && cfg.environmentFile != null)
+          (builtins.throw "services.mithril.configFile and services.mithril.environmentFile cannot both be set.");
       }
       (lib.mkIf (effectiveGenerate && pkgs.stdenv.isDarwin) {
         xdg.configFile."mithril/config.toml".source = shared.mkConfigToml {

nix/modules/nixos/service.nix

@@ -23,30 +23,61 @@
     if cfg.storage.singleDisk.mountPoint != null
     then "${escapeSystemdPath cfg.storage.singleDisk.mountPoint}.mount"
     else null;
+  fileLoggingEnabled = cfg.configSchema.logTarget == "file" || cfg.configSchema.logTarget == "both";
+  hasExternalStorage =
+    cfg.storage.singleDisk.enable
+    || cfg.storage.accounts.device != null
+    || cfg.storage.blocks.device != null;
   shared = import ../shared/lib.nix {inherit lib pkgs;};
   configTemplate = shared.mkConfigTomlTemplate {
     inherit cfg;
-    accountsPath = "@STATE_DIRECTORY@/accounts";
-    blocksRoot = "@STATE_DIRECTORY@/blocks";
-    logsPath = "@LOGS_DIRECTORY@";
+    accountsPath =
+      if cfg.storage.accounts.mountPoint != null
+      then cfg.storage.accounts.mountPoint
+      else "@STATE_DIRECTORY@/accounts";
+    blocksRoot =
+      if cfg.storage.blocks.mountPoint != null
+      then cfg.storage.blocks.mountPoint
+      else "@STATE_DIRECTORY@/blocks";
+    logsPath =
+      if fileLoggingEnabled
+      then "@LOGS_DIRECTORY@"
+      else "@STATE_DIRECTORY@/logs";
   };
   mkdirsScript = pkgs.writeShellScript "mithril-mkdirs" ''
     set -euo pipefail
+    ${lib.optionalString hasExternalStorage ''
+      # External storage mounts are root-owned after mkfs.
+      # Chown mount point roots so the DynamicUser can write.
+      if [ -n "${singleDiskMountPoint}" ]; then
+        chown "${cfg.user}:${cfg.group}" "${singleDiskMountPoint}"
+      fi
+      ${lib.optionalString (cfg.storage.accounts.device != null) ''
+        if [ -n "${accountsMountPoint}" ]; then
+          chown "${cfg.user}:${cfg.group}" "${accountsMountPoint}"
+        fi
+      ''}
+      ${lib.optionalString (cfg.storage.blocks.device != null) ''
+        if [ -n "${blocksMountPoint}" ]; then
+          chown "${cfg.user}:${cfg.group}" "${blocksMountPoint}"
+        fi
+      ''}
+    ''}
     if [ -n "${accountsMountPoint}" ]; then
-      install -d -m 0755 -o ${cfg.user} -g ${cfg.group} "${accountsMountPoint}"
+      install -d -m 0755 ${lib.optionalString hasExternalStorage "-o ${cfg.user} -g ${cfg.group}"} "${accountsMountPoint}"
     fi
     if [ -n "${blocksMountPoint}" ]; then
-      install -d -m 0755 -o ${cfg.user} -g ${cfg.group} "${blocksMountPoint}"
+      install -d -m 0755 ${lib.optionalString hasExternalStorage "-o ${cfg.user} -g ${cfg.group}"} "${blocksMountPoint}"
     fi
     if [ -n "${logsMountPoint}" ]; then
-      install -d -m 0755 -o ${cfg.user} -g ${cfg.group} "${logsMountPoint}"
+      install -d -m 0755 ${lib.optionalString hasExternalStorage "-o ${cfg.user} -g ${cfg.group}"} "${logsMountPoint}"
     fi
   '';
   configInitScript = pkgs.writeShellScript "mithril-generate-config" ''
     set -euo pipefail
     config_dir="$CONFIGURATION_DIRECTORY"
     state_dir="$STATE_DIRECTORY"
-    logs_dir="$LOGS_DIRECTORY"
+    logs_dir="''${LOGS_DIRECTORY:-}"
     runtime_dir="$RUNTIME_DIRECTORY"
     mkdir -p "$config_dir"
     mkdir -p "$runtime_dir"
@@ -90,6 +121,10 @@
     ' "$config_dir/config.toml" > "$runtime_dir/config.toml.tmp"
     mv "$runtime_dir/config.toml.tmp" "$config_dir/config.toml"
   '';
+  singleDiskMountPoint =
+    if cfg.storage.singleDisk.mountPoint != null
+    then cfg.storage.singleDisk.mountPoint
+    else "";
   accountsMountPoint =
     if cfg.storage.accounts.mountPoint != null
     then cfg.storage.accounts.mountPoint
@@ -99,7 +134,7 @@
     then cfg.storage.blocks.mountPoint
     else "";
   logsMountPoint =
-    if cfg.configSchema.storageLogs != null
+    if fileLoggingEnabled && cfg.configSchema.storageLogs != null
     then cfg.configSchema.storageLogs
     else "";
 in {
@@ -131,8 +166,8 @@ in {
           ++ lib.optional (cfg.storage.blocks.device != null && blocksMountUnit != null) blocksMountUnit;
 
         serviceConfig.ExecStartPre =
-          [mkdirsScript]
-          ++ lib.optionals (effectiveGenerate && cfg.configFile == null) [configInitScript];
+          ["+${mkdirsScript}"]
+          ++ lib.optionals (effectiveGenerate && cfg.configFile == null) ["+${configInitScript}"];
       };
 
       mithril-thp = lib.mkIf cfg.performance.enable {