From 4c4bb33ad85f893bf976ab69bb0775137b13266d Mon Sep 17 00:00:00 2001
From: Sam Simpson <sam.simpson@digital.cabinet-office.gov.uk>
Date: Wed, 3 Jan 2024 16:01:40 +0000
Subject: [PATCH] Add overdue scheduled publishing metric

This is a replacement for the old overdue scheduled publishing alert in Icinga
---
 config/initializers/prometheus.rb                  |  4 +++-
 .../scheduled_publishing_overdue_collector.rb      | 14 ++++++++++++++
 2 files changed, 17 insertions(+), 1 deletion(-)
 create mode 100644 lib/collectors/scheduled_publishing_overdue_collector.rb

diff --git a/config/initializers/prometheus.rb b/config/initializers/prometheus.rb
index 4b842d8413b..7c051946609 100644
--- a/config/initializers/prometheus.rb
+++ b/config/initializers/prometheus.rb
@@ -1,2 +1,4 @@
 require "govuk_app_config/govuk_prometheus_exporter"
-GovukPrometheusExporter.configure
+require "collectors/scheduled_publishing_overdue_collector"
+
+GovukPrometheusExporter.configure(collectors: [Collectors::ScheduledPublishingOverdueCollector])
diff --git a/lib/collectors/scheduled_publishing_overdue_collector.rb b/lib/collectors/scheduled_publishing_overdue_collector.rb
new file mode 100644
index 00000000000..c4760d0c4d9
--- /dev/null
+++ b/lib/collectors/scheduled_publishing_overdue_collector.rb
@@ -0,0 +1,14 @@
+module Collectors
+  class ScheduledPublishingOverdueCollector < PrometheusExporter::Server::CollectorBase
+    def type
+      "whitehall"
+    end
+
+    def metrics
+      whitehall_scheduled_publishing_overdue = PrometheusExporter::Metric::Gauge.new("whitehall_scheduled_publishing_overdue", "Overdue scheduled publications")
+      whitehall_scheduled_publishing_overdue.observe(Edition.due_for_publication.count)
+
+      [whitehall_scheduled_publishing_overdue]
+    end
+  end
+end