From 24467a7bdede3945dcbec4a35454931a7571848d Mon Sep 17 00:00:00 2001
From: Your Name <graham@grahamc.com>
Date: Tue, 24 Aug 2021 11:35:38 -0400
Subject: [PATCH] Nix::getHydraNotifyPrometheusConfig: print errors if the
 configuration provided is invalid.

---
 src/lib/Hydra/Helper/Nix.pm | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/src/lib/Hydra/Helper/Nix.pm b/src/lib/Hydra/Helper/Nix.pm
index ac0e54cf..bd294b73 100644
--- a/src/lib/Hydra/Helper/Nix.pm
+++ b/src/lib/Hydra/Helper/Nix.pm
@@ -74,12 +74,22 @@ sub getHydraNotifyPrometheusConfig {
     my ($config) = @_;
     my $cfg = $config->{hydra_notify};
 
-    if (!defined($cfg) || ref $cfg ne "HASH") {
+    if (!defined($cfg)) {
+        return undef;
+    }
+
+    if (ref $cfg ne "HASH") {
+        print STDERR "Error reading Hydra's configuration file: hydra_notify should be a block.\n";
         return undef;
     }
 
     my $cfg = $cfg->{prometheus};
-    if (!defined($cfg) || ref $cfg ne "HASH") {
+    if (!defined($cfg)) {
+        return undef;
+    }
+
+    if (ref $cfg ne "HASH") {
+        print STDERR "Error reading Hydra's configuration file: hydra_notify.prometheus should be a block.\n";
         return undef;
     }
 
@@ -88,6 +98,9 @@ sub getHydraNotifyPrometheusConfig {
             "listen_address" => $cfg->{'listen_address'},
             "port" => $cfg->{'port'},
         };
+    } else {
+        print STDERR "Error reading Hydra's configuration file: hydra_notify.prometheus should include listen_address and port.\n";
+        return undef;
     }
 
     return undef;