nixos/prometheus-exporters: add option renaming for submodules

Adds the functionality to create option renamings and removals
for exporter submodules as in nixos/modules/rename.nix.

nixos/modules/services/monitoring/prometheus/exporters.nix

@@ -102,9 +102,10 @@ let
     };
   });
 
-  mkSubModule = { name, port, extraOpts, ... }: {
+  mkSubModule = { name, port, extraOpts, imports }: {
     ${name} = mkOption {
       type = types.submodule {
+        inherit imports;
         options = (mkExporterOpts {
           inherit name port;
         } // extraOpts);
@@ -117,13 +118,15 @@ let
   mkSubModules = (foldl' (a: b: a//b) {}
     (mapAttrsToList (name: opts: mkSubModule {
       inherit name;
-      inherit (opts) port serviceOpts;
+      inherit (opts) port;
       extraOpts = opts.extraOpts or {};
+      imports = opts.imports or [];
     }) exporterOpts)
   );
 
   mkExporterConf = { name, conf, serviceOpts }:
     mkIf conf.enable {
+      warnings = conf.warnings or [];
       networking.firewall.extraCommands = mkIf conf.openFirewall (concatStrings [
         "ip46tables -A nixos-fw ${conf.firewallFilter} "
         "-m comment --comment ${name}-exporter -j nixos-fw-accept"

nixos/modules/services/monitoring/prometheus/exporters.xml

@@ -113,7 +113,7 @@
      specific options and configuration:
 <programlisting>
 # nixpgs/nixos/modules/services/prometheus/exporters/postfix.nix
-{ config, lib, pkgs }:
+{ config, lib, pkgs, options }:
 
 with lib;
 
@@ -184,4 +184,42 @@ in
    </listitem>
   </itemizedlist>
  </section>
+ <section xml:id="module-services-prometheus-exporters-update-exporter-module">
+  <title>Updating an exporter module</title>
+   <para>
+     Should an exporter option change at some point, it is possible to add
+     information about the change to the exporter definition similar to
+     <literal>nixpkgs/nixos/modules/rename.nix</literal>:
+<programlisting>
+{ config, lib, pkgs, options }:
+
+with lib;
+
+let
+  cfg = config.services.prometheus.exporters.nginx;
+in
+{
+  port = 9113;
+  extraOpts = {
+    # additional module options
+    # ...
+  };
+  serviceOpts = {
+    # service configuration
+    # ...
+  };
+  imports = [
+    # 'services.prometheus.exporters.nginx.telemetryEndpoint' -> 'services.prometheus.exporters.nginx.telemetryPath'
+    (mkRenamedOptionModule [ "telemetryEndpoint" ] [ "telemetryPath" ])
+
+    # removed option 'services.prometheus.exporters.nginx.insecure'
+    (mkRemovedOptionModule [ "insecure" ] ''
+      This option was replaced by 'prometheus.exporters.nginx.sslVerify' which defaults to true.
+    '')
+    ({ options.warnings = options.warnings; })
+  ];
+}
+</programlisting>
+    </para>
+  </section>
 </chapter>