nixos/mastodon: use redis.servers

nixos/doc/manual/from_md/release-notes/rl-2205.section.xml

@@ -1879,6 +1879,37 @@
           during the time when the timer was inactive.
         </para>
       </listitem>
+      <listitem>
+        <para>
+          Mastodon now uses <literal>services.redis.servers</literal> to
+          start a new redis server, instead of using a global redis
+          server. This improves compatibility with other services that
+          use redis.
+        </para>
+        <para>
+          Note that this will recreate the redis database, although
+          according to the
+          <link xlink:href="https://docs.joinmastodon.org/admin/backups/">Mastodon
+          docs</link>, this is almost harmless:
+        </para>
+        <blockquote>
+          <para>
+            Losing the Redis database is almost harmless: The only
+            irrecoverable data will be the contents of the Sidekiq
+            queues and scheduled retries of previously failed jobs. The
+            home and list feeds are stored in Redis, but can be
+            regenerated with tootctl.
+          </para>
+        </blockquote>
+        <para>
+          If you do want to save the redis database, you can use the
+          following commands:
+        </para>
+        <programlisting language="bash">
+redis-cli save
+cp /var/lib/redis/dump.rdb &quot;/var/lib/redis-mastodon/dump.rdb&quot;
+</programlisting>
+      </listitem>
       <listitem>
         <para>
           If you are using Wayland you can choose to use the Ozone

nixos/doc/manual/release-notes/rl-2205.section.md

@@ -699,6 +699,20 @@ In addition to numerous new and upgraded packages, this release has the followin
   By default auto-upgrade will now run immediately if it would have been triggered at least
   once during the time when the timer was inactive.
 
+- Mastodon now uses `services.redis.servers` to start a new redis server, instead of using a global redis server. 
+  This improves compatibility with other services that use redis.
+  
+  Note that this will recreate the redis database, although according to the [Mastodon docs](https://docs.joinmastodon.org/admin/backups/), 
+  this is almost harmless:
+  > Losing the Redis database is almost harmless: The only irrecoverable data will be the contents of the Sidekiq queues and scheduled retries of previously failed jobs. 
+  >  The home and list feeds are stored in Redis, but can be regenerated with tootctl.
+  
+  If you do want to save the redis database, you can use the following commands:
+  ```bash
+  redis-cli save
+  cp /var/lib/redis/dump.rdb "/var/lib/redis-mastodon/dump.rdb"
+  ```
+
 - If you are using Wayland you can choose to use the Ozone Wayland support
   in Chrome and several Electron apps by setting the environment variable
   `NIXOS_OZONE_WL=1` (for example via

nixos/modules/services/web-apps/mastodon.nix

@@ -294,7 +294,7 @@ in {
         port = lib.mkOption {
           description = "Redis port.";
           type = lib.types.port;
-          default = 6379;
+          default = 31637;
         };
       };
 
@@ -605,8 +605,10 @@ in {
       enable = true;
       hostname = lib.mkDefault "${cfg.localDomain}";
     };
-    services.redis = lib.mkIf (cfg.redis.createLocally && cfg.redis.host == "127.0.0.1") {
+    services.redis.servers.mastodon = lib.mkIf (cfg.redis.createLocally && cfg.redis.host == "127.0.0.1") {
       enable = true;
+      port = cfg.redis.port;
+      bind = "127.0.0.1";
     };
     services.postgresql = lib.mkIf databaseActuallyCreateLocally {
       enable = true;