From 84abcc05e87e275afdddc83df24b9a16cbe681d2 Mon Sep 17 00:00:00 2001
From: Sebastien Bourdeauducq <sb@m-labs.hk>
Date: Sun, 17 Feb 2019 12:33:27 +0800
Subject: [PATCH] enable useSubstitutes for hydra

This prevents rebuilds of nixpkgs, and those rebuilds getting stuck due to missing features
on the default buildslave.

Thanks cleverca22 for figuring this out.
---
 nixbld-etc-nixos/configuration.nix | 1 +
 1 file changed, 1 insertion(+)

diff --git a/nixbld-etc-nixos/configuration.nix b/nixbld-etc-nixos/configuration.nix
index f636216..638ce6c 100644
--- a/nixbld-etc-nixos/configuration.nix
+++ b/nixbld-etc-nixos/configuration.nix
@@ -126,6 +126,7 @@ ACTION=="add", SUBSYSTEM=="tty", \
   services.hydra = {
     enable = true;
     package = pkgs.callPackage ./hydra.nix {};
+    useSubstitutes = true;
     hydraURL = "https://nixbld.m-labs.hk";
     notificationSender = "hydra@m-labs.hk";
     minimumDiskFree = 2;  # in GB