Allow query/query_range key contain numbers

A number is a valid Prometheus query. Such queries are usually used
to display a threshold on a chart.

changelogs/unreleased/rpereira2-allow-numbers-in-dashboard-query-key.yml

+---
+title: Allow query/query_range keys in metrics dashboard to contain numbers
+merge_request: 39530
+author:
+type: changed

lib/gitlab/metrics/dashboard/stages/metric_endpoint_inserter.rb

@@ -47,7 +47,7 @@ module Gitlab
 
             # We need to remove any newlines since our UrlBlocker does not allow
             # multiline URLs.
-            query.squish
+            query.to_s.squish
           end
         end
       end

lib/gitlab/metrics/dashboard/validator/schemas/metric.json

@@ -9,8 +9,8 @@
 		 },
 		"unit": { "type": "string" },
 		"label": { "type": "string" },
-		"query": { "type": "string" },
-		"query_range": { "type": "string" },
+		"query": { "type": ["string", "number"] },
+		"query_range": { "type": ["string", "number"] },
 		"step": { "type": "number" }
 	}
 }

spec/fixtures/lib/gitlab/metrics/dashboard/sample_dashboard.yml

@@ -48,7 +48,7 @@ panel_groups:
     y_label: "y_label"
     metrics:
     - id: metric_a2
-      query_range: 'query'
+      query_range: 2000
       label: Legend Label
       unit: unit
   - title: "Super Chart A1"

spec/fixtures/lib/gitlab/metrics/dashboard/schemas/metrics.json

@@ -10,8 +10,8 @@
   ],
   "properties": {
     "id": { "type": "string" },
-    "query_range": { "type": "string" },
-    "query": { "type": "string" },
+    "query_range": { "type": ["string", "number"] },
+    "query": { "type": ["string", "number"] },
     "unit": { "type": "string" },
     "label": { "type": "string" },
     "track": { "type": "string" },

spec/lib/gitlab/metrics/dashboard/stages/metric_endpoint_inserter_spec.rb

@@ -27,9 +27,17 @@ RSpec.describe Gitlab::Metrics::Dashboard::Stages::MetricEndpointInserter do
       transform!
 
       expect(all_metrics).to satisfy_all do |metric|
-        metric[:prometheus_endpoint_path] == prometheus_path(metric[:query_range].squish)
+        metric[:prometheus_endpoint_path].present? && !metric[:prometheus_endpoint_path].include?("\n")
       end
     end
+
+    it 'works when query/query_range is a number' do
+      query = 2000
+
+      transform!
+
+      expect(all_metrics[1][:prometheus_endpoint_path]).to eq(prometheus_path(query))
+    end
   end
 
   private