nixos/mastodon: Fix sidekiq's DB_POOL, add configurable concurrency

The `services.mastodon` module currently hardcodes sidekiq's concurrency
to 25, but doesn't set a DB pool size, which defaults to 5 or the number
of configured web threads.

(This behaviour is very strange, and arguably a mastodon bug.)

This also makes sidekiq's concurrency configurable, because 25 is a tad
high for the hardware I'm running it on.

1 files changed, 8 insertions, 2 deletions

diff --git a/nixos/modules/services/web-apps/mastodon.nix b/nixos/modules/services/web-apps/mastodon.nix
index 5e24bd06ffdb..e3bc70791cfb 100644
--- a/nixos/modules/services/web-apps/mastodon.nix
+++ b/nixos/modules/services/web-apps/mastodon.nix
@@ -154,10 +154,15 @@ in {
       };
 
       sidekiqPort = lib.mkOption {
-        description = "TCP port used by the mastodon-sidekiq service";
+        description = "TCP port used by the mastodon-sidekiq service.";
         type = lib.types.port;
         default = 55002;
       };
+      sidekiqThreads = lib.mkOption {
+        description = "Worker threads used by the mastodon-sidekiq service.";
+        type = lib.types.int;
+        default = 25;
+      };
 
       vapidPublicKeyFile = lib.mkOption {
         description = ''
@@ -524,9 +529,10 @@ in {
       wantedBy = [ "multi-user.target" ];
       environment = env // {
         PORT = toString(cfg.sidekiqPort);
+        DB_POOL = toString cfg.sidekiqThreads;
       };
       serviceConfig = {
-        ExecStart = "${cfg.package}/bin/sidekiq -c 25 -r ${cfg.package}";
+        ExecStart = "${cfg.package}/bin/sidekiq -c ${toString cfg.sidekiqThreads} -r ${cfg.package}";
         Restart = "always";
         RestartSec = 20;
         EnvironmentFile = "/var/lib/mastodon/.secrets_env";