Remove newlines when generating Prometheus endpoint path

Remove newlines when generating prometheus_endpoint_path for metrics
dashboards. This is required since our UrlBlocker does not allow
multiline URLs.

changelogs/unreleased/220338-remove-newlines-in-prom-queries.yml

+---
+title: Allow multiline Prometheus queries in metrics dashboards yaml
+merge_request: 34508
+author:
+type: changed

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

@@ -45,7 +45,9 @@ module Gitlab
 
             raise Errors::MissingQueryError.new('Each "metric" must define one of :query or :query_range') unless query
 
-            query
+            # We need to remove any newlines since our UrlBlocker does not allow
+            # multiline URLs.
+            query.squish
           end
         end
       end

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

@@ -41,7 +41,17 @@ panel_groups:
     max_value: 1
     metrics:
     - id: metric_a1
-      query_range: 'query'
+      query_range: |+
+        avg(
+          sum(
+            container_memory_usage_bytes{
+              container_name!="POD",
+              pod_name=~"^{{ci_environment_slug}}-(.*)",
+              namespace="{{kube_namespace}}"
+            }
+          ) by (job)
+        ) without (job)
+        /1024/1024/1024
       unit: unit
       label: Legend Label
   - title: "Super Chart A2"

spec/lib/gitlab/metrics/dashboard/processor_spec.rb

@@ -26,12 +26,6 @@ RSpec.describe Gitlab::Metrics::Dashboard::Processor do
     let(:process_params) { [project, dashboard_yml, sequence, { environment: environment }] }
     let(:dashboard) { described_class.new(*process_params).process }
 
-    it 'includes a path for the prometheus endpoint with each metric' do
-      expect(all_metrics).to satisfy_all do |metric|
-        metric[:prometheus_endpoint_path] == prometheus_path(metric[:query_range])
-      end
-    end
-
     it 'includes an id for each dashboard panel' do
       expect(all_panels).to satisfy_all do |panel|
         panel[:id].present?

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

+# frozen_string_literal: true
+
+require 'spec_helper'
+
+RSpec.describe Gitlab::Metrics::Dashboard::Stages::MetricEndpointInserter do
+  include MetricsDashboardHelpers
+
+  let(:project) { build_stubbed(:project) }
+  let(:environment) { build_stubbed(:environment, project: project) }
+
+  describe '#transform!' do
+    subject(:transform!) { described_class.new(project, dashboard, environment: environment).transform! }
+
+    let(:dashboard) { load_sample_dashboard.deep_symbolize_keys }
+
+    it 'generates prometheus_endpoint_path without newlines' do
+      query = 'avg( sum( container_memory_usage_bytes{ container_name!="POD", '\
+      'pod_name=~"^{{ci_environment_slug}}-(.*)", namespace="{{kube_namespace}}" } ) '\
+      'by (job) ) without (job) /1024/1024/1024'
+
+      transform!
+
+      expect(all_metrics[0][:prometheus_endpoint_path]).to eq(prometheus_path(query))
+    end
+
+    it 'includes a path for the prometheus endpoint with each metric' do
+      transform!
+
+      expect(all_metrics).to satisfy_all do |metric|
+        metric[:prometheus_endpoint_path] == prometheus_path(metric[:query_range].squish)
+      end
+    end
+  end
+
+  private
+
+  def all_metrics
+    dashboard[:panel_groups].flat_map do |group|
+      group[:panels].flat_map { |panel| panel[:metrics] }
+    end
+  end
+
+  def prometheus_path(query)
+    Gitlab::Routing.url_helpers.prometheus_api_project_environment_path(
+      project,
+      environment,
+      proxy_path: :query_range,
+      query: query
+    )
+  end
+end