Merge branch 'dev/user-maildir' into 'master'

Support customized maildir type and location per virtual user

See merge request simple-nixos-mailserver/nixos-mailserver!347

default.nix

@@ -140,6 +140,60 @@ in
             '';
           };
 
+          customMaildir = mkOption {
+            type = types.nullOr (types.submodule ({ name, ...}: {
+              options = {
+                uid = mkOption {
+                  type = types.int;
+                  example = 1000;
+                  description = ''
+                    User ID for files and directories in the maildir. Files and
+                    directories created by Dovecot will be assigned this UID.
+                  '';
+                };
+
+                gid = mkOption {
+                  type = types.int;
+                  example = 1000;
+                  description = ''
+                    Group ID for files and directories in the maildir. Files and
+                    directories created by Dovecot will be assigned this GID.
+                  '';
+                };
+
+                dovecotHome = mkOption {
+                  type = types.str;
+                  example = "/home/myusername";
+                  description = ''
+                    Home directory for Dovecot virtual user. This is used to
+                    maintain mail user's private state. This MUST be different
+                    for each Dovecot virtual user and MUST be an absolute path.
+                    Refer to the Dovecot documentation for further information
+                    on this configuration option:
+                    https://wiki.dovecot.org/VirtualUsers/Home
+                  '';
+                };
+
+                mailDirectorySpec = mkOption {
+                  type = types.str;
+                  example = "maildir:~/mail";
+                  description = ''
+                    Dovecot mail location specification. Refer to the Dovecot
+                    documentation for further information on this configuration
+                    option:
+                    https://doc.dovecot.org/configuration_manual/mail_location/
+                  '';
+                };
+              };
+            }));
+            default = null;
+            description = ''
+              Configuration options for a custom Maildir location. For instance,
+              this can be used to implement home-directory Maildirs for specific
+              users only. If null, a Maildir under /var/vmail will be assigned.
+            '';
+          };
+
           sieveScript = mkOption {
             type = with types; nullOr lines;
             default = null;

mail-server/dovecot.nix

@@ -102,10 +102,36 @@ let
     EOF
 
     cat <<EOF > ${userdbFile}
-    ${lib.concatStringsSep "\n" (lib.mapAttrsToList (name: value:
-      "${name}:::::::"
-        + lib.optionalString (value.quota != null) "userdb_quota_rule=*:storage=${value.quota}"
-    ) cfg.loginAccounts)}
+    ${lib.concatStringsSep "\n" (
+      lib.mapAttrsToList (name: value: let
+        # Space-separated "extra fields" options, appended as the 8-th element
+        # in a userdb entry tuple in passwd format:
+        # $user:$passwd:$uid:$gid:$uidinfo:$home:$shell:$extraFields
+        extraFieldsStr = lib.concatStringsSep " " (
+          # Custom Maildir location option:
+          (lib.optional
+            (value.customMaildir != null)
+            "userdb_mail=${value.customMaildir.mailDirectorySpec}")
+          ++
+          # Quota option:
+          (lib.optional
+            (value.quota != null)
+            "userdb_quota_rule=*:storage=${value.quota}")
+        );
+      in (
+        if value.customMaildir == null then
+          "${name}:::::::${extraFieldsStr}"
+        else
+          "${name}"
+          + ":"
+          + ":${builtins.toString value.customMaildir.uid}"
+          + ":${builtins.toString value.customMaildir.gid}"
+          + ":"
+          + ":${value.customMaildir.dovecotHome}"
+          + ":/run/current-system/sw/bin/nologin"
+          + ":${extraFieldsStr}"
+      )) cfg.loginAccounts
+    )}
     EOF
   '';