From a1cb0717730f775f4150aac23b9aab5285a2c2cb Mon Sep 17 00:00:00 2001
From: teutat3s <teutates@mailbox.org>
Date: Sat, 25 Feb 2023 17:54:47 +0100
Subject: [PATCH] mailman: trigger postfix reload when caddy renews

TLS Let's Encrypt certificates
---
 hosts/flora-6/mailman.nix | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/hosts/flora-6/mailman.nix b/hosts/flora-6/mailman.nix
index 2ac2dbc7..955723d4 100644
--- a/hosts/flora-6/mailman.nix
+++ b/hosts/flora-6/mailman.nix
@@ -29,6 +29,31 @@ in {
     hostname = "list.pub.solar";
   };
 
+  systemd.paths.watcher-caddy-ssl-file = {
+    description = "Watches for changes in caddy's TLS cert file (after renewals) to reload postfix";
+    documentation = ["systemd.path(5)"];
+    partOf = ["postfix-reload.service"];
+    pathConfig = {
+      PathChanged = "/var/lib/caddy/.local/share/caddy/certificates/acme-v02.api.letsencrypt.org-directory/list.pub.solar/list.pub.solar.crt";
+      Unit = "postfix-reload.service";
+    };
+    wantedBy = ["multi-user.target"];
+  };
+
+  systemd.services."postfix-reload" = {
+    description = "Reloads postfix config, e.g. after TLS certs change, notified by watcher-caddy-ssl-file.path";
+    documentation = ["systemd.path(5)"];
+    requires = ["postfix.service"];
+    after = ["postfix.service"];
+    startLimitIntervalSec = 10;
+    startLimitBurst = 5;
+    serviceConfig.Type = "oneshot";
+    script = ''
+      ${pkgs.systemd}/bin/systemctl reload postfix
+    '';
+    wantedBy = ["multi-user.target"];
+  };
+
   services.mailman = {
     enable = true;
     # We use caddy instead of nginx