From 07a7baeb6bf21ce2018fc558fb849ba17669fb89 Mon Sep 17 00:00:00 2001
From: Joe Mou <dev@mou.fo>
Date: Fri, 26 Apr 2024 23:51:10 -0400
Subject: elmo: E-mail on certain systemd failures

---
 hostnix/elmo/configuration.nix |  2 ++
 hostnix/elmo/dyndns.nix        |  1 +
 hostnix/elmo/email.nix         |  3 +++
 hostnix/elmo/system.nix        | 21 ++++++++++++++++++++-
 4 files changed, 26 insertions(+), 1 deletion(-)

(limited to 'hostnix')

diff --git a/hostnix/elmo/configuration.nix b/hostnix/elmo/configuration.nix
index 6945fa5..444dc5b 100644
--- a/hostnix/elmo/configuration.nix
+++ b/hostnix/elmo/configuration.nix
@@ -39,6 +39,8 @@
     dig
     file
     gitFull
+    openssl
+    psmisc
     tmux
     tree
   ];
diff --git a/hostnix/elmo/dyndns.nix b/hostnix/elmo/dyndns.nix
index aea6776..5bfde47 100644
--- a/hostnix/elmo/dyndns.nix
+++ b/hostnix/elmo/dyndns.nix
@@ -30,6 +30,7 @@
       # Defer errors for ~45min, throttle e-mails to ~hourly.
       StartLimitIntervalSec = "1hr";
       StartLimitBurst = "45";
+      OnFailure = "status-email@%n.service";
     };
     serviceConfig = {
       Type = "oneshot";
diff --git a/hostnix/elmo/email.nix b/hostnix/elmo/email.nix
index 462a3d7..1ea4000 100644
--- a/hostnix/elmo/email.nix
+++ b/hostnix/elmo/email.nix
@@ -17,6 +17,9 @@
   systemd.services.postfix-tls-rotate = {
     requires = [ "network-online.target" ];
     after = [ "network-online.target" ];
+    unitConfig = {
+      OnFailure = "status-email@%n.service";
+    };
     serviceConfig = {
       Type = "oneshot";
       # Not really necessary indirection but interesting to try out. Note we
diff --git a/hostnix/elmo/system.nix b/hostnix/elmo/system.nix
index 4f6ddb7..407ca42 100644
--- a/hostnix/elmo/system.nix
+++ b/hostnix/elmo/system.nix
@@ -34,11 +34,30 @@
   # https://nixos.wiki/wiki/Hardware/Apple#Auto_Restart
   systemd.services.enable-autorestart = {
     description = "Boot after power failure (server mode)";
-    wantedBy = [ "default.target" ];
+    wantedBy = [ "multi-user.target" ];
     serviceConfig = {
       Type = "oneshot";
     };
     # https://superuser.com/a/1051137
     script = "${pkgs.pciutils}/bin/setpci -s 00:1f.0 0xa4.b=0";
   };
+
+  # https://wiki.archlinux.org/index.php/Systemd/Timers#MAILTO
+  systemd.services."status-email@" = {
+    description = "Status email for %i";
+    serviceConfig = {
+      Type = "oneshot";
+    };
+    scriptArgs = "%i";
+    script = ''
+      ${pkgs.mailutils}/bin/mail -s "$1 status" root <<EOF
+      From: systemd <root>
+      Subject: $1 status
+      Content-Transfer-Encoding: 8bit
+      Content-Type: text/plain; charset=UTF-8
+
+      $(systemctl status --full "$1")
+      EOF
+    '';
+  };
 }
-- 
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