refactor(ops): Split //ops/nixos into different locations r/2482

Splits //ops/nixos into:

* //ops/nixos.nix - utility functions for building systems
* //ops/machines - shared machine definitions (read by readTree)
* //ops/modules - shared NixOS modules (skipped by readTree)

This simplifies working with the configuration fixpoint in whitby, and
is overall a bit more in line with how NixOS systems in user folders
currently work.

Change-Id: I1322ec5cc76c0207c099c05d44828a3df0b3ffc1
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2931
Tested-by: BuildkiteCI
Reviewed-by: sterni <sternenseemann@systemli.org>
Reviewed-by: glittershark <grfn@gws.fyi>

1 files changed, 24 insertions, 0 deletions

diff --git a/ops/modules/tvl-sso/default.nix b/ops/modules/tvl-sso/default.nix
new file mode 100644
index 0000000000..8e33c708b7
--- /dev/null
+++ b/ops/modules/tvl-sso/default.nix
@@ -0,0 +1,24 @@
+# Configures an Apereo CAS instance for TVL SSO
+{ depot, ... }:
+
+let
+  inherit (depot.third_party) apereo-cas;
+in {
+  config = {
+    environment.systemPackages = [ apereo-cas ];
+    systemd.services.apereo-cas = {
+      description = "Apereo CAS Single Sign On server";
+      wantedBy = [ "multi-user.target" ];
+      after = [ "network.target" ];
+      serviceConfig = {
+        User = "apereo-cas";
+        Group = "apereo-cas";
+        ExecStart = "${apereo-cas}/bin/cas";
+        EnvironmentFile = "/etc/cas/secrets";
+        Restart = "always";
+      };
+    };
+    users.users.apereo-cas = {};
+    users.groups.apereo-cas = {};
+  };
+}