Cleanup implementation and add cluster finding tests

3 files changed, 19 insertions, 18 deletions

diff --git a/app/models/clusters/cluster.rb b/app/models/clusters/cluster.rb
index 5ecbd4cbceb..8678f70f78c 100644
--- a/app/models/clusters/cluster.rb
+++ b/app/models/clusters/cluster.rb
@@ -49,6 +49,9 @@ module Clusters
     scope :enabled, -> { where(enabled: true) }
     scope :disabled, -> { where(enabled: false) }
 
+    scope :for_environment, -> (env) { where(environment_scope: ['*', '', env.slug]) }
+    scope :for_all_environments, -> { where(environment_scope: ['*', '']) }
+
     def status_name
       if provider
         provider.status_name
diff --git a/app/models/environment.rb b/app/models/environment.rb
index d895550784d..bf69b4c50f0 100644
--- a/app/models/environment.rb
+++ b/app/models/environment.rb
@@ -163,18 +163,6 @@ class Environment < ActiveRecord::Base
     end
   end
 
-  def enabled_clusters
-    slug = self.slug
-    result = project.clusters.enabled.select do |cluster|
-      scope = cluster.environment_scope || '*'
-      File.fnmatch(scope, slug)
-    end
-
-    # sort results by descending order based on environment_scope being longer
-    # thus more closely matching environment slug
-    result.sort_by { |cluster| cluster.environment_scope.length }.reverse!
-  end
-
   def slug
     super.presence || generate_slug
   end
diff --git a/app/models/project_services/prometheus_service.rb b/app/models/project_services/prometheus_service.rb
index 2fb94c1facb..580e2c01aaa 100644
--- a/app/models/project_services/prometheus_service.rb
+++ b/app/models/project_services/prometheus_service.rb
@@ -116,31 +116,41 @@ class PrometheusService < MonitoringService
     { success: false, result: err.message }
   end
 
-  def client(environment_id)
+  def client(environment_id = nil)
     if manual_configuration?
       Gitlab::PrometheusClient.new(RestClient::Resource.new(api_url))
     else
       cluster = cluster_with_prometheus(environment_id)
       raise Gitlab::PrometheusError, "couldn't find cluster with Prometheus installed" unless cluster
+      rest_client = client_from_cluster(cluster)
 
-      Gitlab::PrometheusClient.new(cluster.application_prometheus.proxy_client)
+      raise Gitlab::PrometheusError, "couldn't create proxy Prometheus client" unless rest_client
+      Gitlab::PrometheusClient.new(rest_client)
     end
   end
 
   def prometheus_installed?
-    cluster_with_prometheus.present?
+    project.clusters.enabled.any? { |cluster| cluster.application_prometheus&.installed? }
   end
 
   private
 
   def cluster_with_prometheus(environment_id = nil)
     clusters = if environment_id
-                 ::Environment.find_by(id: environment_id).try(:enabled_clusters) || []
+                 ::Environment.find_by(id: environment_id).try do |env|
+                   # sort results by descending order based on environment_scope being longer
+                   # thus more closely matching environment slug
+                   project.clusters.enabled.for_environment(env).sort_by { |c| c.environment_scope&.length }.reverse!
+                 end
                else
-                 project.clusters.enabled.select { |c| c.environment_scope == '*' || c.environment_scope == '' }
+                 project.clusters.enabled.for_all_environments
                end
 
-    clusters.detect { |cluster| cluster.application_prometheus&.installed? }
+    clusters&.detect { |cluster| cluster.application_prometheus&.installed? }
+  end
+
+  def client_from_cluster(cluster)
+    cluster.application_prometheus.proxy_client
   end
 
   def rename_data_to_metrics(metrics)