From 45f3d5a117f336299a34ca1c6eea778da419200a Mon Sep 17 00:00:00 2001
From: Colin <colin@uninsane.org>
Date: Sun, 5 Mar 2023 03:50:04 +0000
Subject: [PATCH] ccache: default to 50G cache

---
 hosts/modules/roles/build-machine.nix | 12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

diff --git a/hosts/modules/roles/build-machine.nix b/hosts/modules/roles/build-machine.nix
index 25ebd6b7..8459680b 100644
--- a/hosts/modules/roles/build-machine.nix
+++ b/hosts/modules/roles/build-machine.nix
@@ -1,4 +1,4 @@
-{ config, lib, ... }:
+{ config, lib, sane-lib, ... }:
 
 let
   inherit (lib) mkIf mkOption types;
@@ -19,11 +19,19 @@ in
 
     # granular compilation cache
     # docs: <https://nixos.wiki/wiki/CCache>
-    # investigate the cache with `nix-cache --show-stats`
+    # investigate the cache with:
+    # - `nix-ccache --show-stats`
+    # - `build '.#ccache'
+    #   - `sudo CCACHE_DIR=/var/cache/ccache ./result/bin/ccache --show-stats -v`
+    # TODO: whitelist `--verbose` in <nixpkgs:nixos/modules/programs/ccache.nix>
+    # TODO: configure without compression (leverage fs-level compression), and enable file-clone (i.e. hardlinks)
     programs.ccache.enable = true;
     sane.persist.sys.plaintext = [
       { group = "nixbld"; mode = "0775"; directory = config.programs.ccache.cacheDir; }
     ];
+    sane.fs."/var/cache/ccache/ccache.conf" = sane-lib.fs.wantedText ''
+      max_size = 50G
+    '';
     nix.settings.extra-sandbox-paths = [ config.programs.ccache.cacheDir ];
     programs.ccache.packageNames = [
       # these have to exist in toplevel package set: