builder: add attic binary cache

systems/x86_64-linux/builder/default.nix

@@ -211,6 +211,11 @@
       locations."/".proxyPass =
         "http://${config.services.nix-serve.bindAddress}:${toString config.services.nix-serve.port}";
     };
+
+    clientMaxBodySize = "2G";
+    virtualHosts."cache.julian-mutter.de" = {
+      locations."/".proxyPass = "http://127.0.0.1:8080";
+    };
   };
 
   # =========== Gitea actions ==========
@@ -242,6 +247,42 @@
     secretKeyFile = "/var/cache-priv-key.pem";
   };
 
+  # =========== Binary Cache with attic ==========
+  sops.secrets."attic_token".sopsFile = ../../../secrets/secrets-builder.yaml;
+
+  services.atticd = {
+    enable = true;
+    environmentFile = config.sops.secrets."attic_token".path;
+    settings = {
+      listen = "[::]:8080";
+
+      jwt = { };
+
+      # Data chunking
+      #
+      # Warning: If you change any of the values here, it will be
+      # difficult to reuse existing chunks for newly-uploaded NARs
+      # since the cutpoints will be different. As a result, the
+      # deduplication ratio will suffer for a while after the change.
+      chunking = {
+        # The minimum NAR size to trigger chunking
+        #
+        # If 0, chunking is disabled entirely for newly-uploaded NARs.
+        # If 1, all NARs are chunked.
+        nar-size-threshold = 64 * 1024; # 64 KiB
+
+        # The preferred minimum size of a chunk, in bytes
+        min-size = 16 * 1024; # 16 KiB
+
+        # The preferred average size of a chunk, in bytes
+        avg-size = 64 * 1024; # 64 KiB
+
+        # The preferred maximum size of a chunk, in bytes
+        max-size = 256 * 1024; # 256 KiB
+      };
+    };
+  };
+
   # ======================== DO NOT CHANGE THIS ========================
   system.stateVersion = "23.11";
   # ======================== DO NOT CHANGE THIS ========================