Refactor common metrics importer

This refactors common metrics importer for two reasons. 1. To create a
new pattern that can be followed by future importers that will minimize
dependency collision and 2. To allow EE to more easily extend
dependencies.

2 files changed, 72 insertions, 63 deletions

diff --git a/app/models/prometheus_metric.rb b/app/models/prometheus_metric.rb
index 62090444f79..b8e7673dcf5 100644
--- a/app/models/prometheus_metric.rb
+++ b/app/models/prometheus_metric.rb
@@ -3,68 +3,7 @@
 class PrometheusMetric < ApplicationRecord
   belongs_to :project, validate: true, inverse_of: :prometheus_metrics
 
-  enum group: {
-    # built-in groups
-    nginx_ingress_vts: -1,
-    ha_proxy: -2,
-    aws_elb: -3,
-    nginx: -4,
-    kubernetes: -5,
-    nginx_ingress: -6,
-
-    # custom/user groups
-    business: 0,
-    response: 1,
-    system: 2
-  }
-
-  GROUP_DETAILS = {
-    # built-in groups
-    nginx_ingress_vts: {
-      group_title: _('Response metrics (NGINX Ingress VTS)'),
-      required_metrics: %w(nginx_upstream_responses_total nginx_upstream_response_msecs_avg),
-      priority: 10
-    }.freeze,
-    nginx_ingress: {
-      group_title: _('Response metrics (NGINX Ingress)'),
-      required_metrics: %w(nginx_ingress_controller_requests nginx_ingress_controller_ingress_upstream_latency_seconds_sum),
-      priority: 10
-    }.freeze,
-    ha_proxy: {
-      group_title: _('Response metrics (HA Proxy)'),
-      required_metrics: %w(haproxy_frontend_http_requests_total haproxy_frontend_http_responses_total),
-      priority: 10
-    }.freeze,
-    aws_elb: {
-      group_title: _('Response metrics (AWS ELB)'),
-      required_metrics: %w(aws_elb_request_count_sum aws_elb_latency_average aws_elb_httpcode_backend_5_xx_sum),
-      priority: 10
-    }.freeze,
-    nginx: {
-      group_title: _('Response metrics (NGINX)'),
-      required_metrics: %w(nginx_server_requests nginx_server_requestMsec),
-      priority: 10
-    }.freeze,
-    kubernetes: {
-      group_title: _('System metrics (Kubernetes)'),
-      required_metrics: %w(container_memory_usage_bytes container_cpu_usage_seconds_total),
-      priority: 5
-    }.freeze,
-
-    # custom/user groups
-    business: {
-      group_title: _('Business metrics (Custom)'),
-      priority: 0
-    }.freeze,
-    response: {
-      group_title: _('Response metrics (Custom)'),
-      priority: -5
-    }.freeze,
-    system: {
-      group_title: _('System metrics (Custom)'),
-      priority: -10
-    }.freeze
-  }.freeze
+  enum group: PrometheusMetricEnums.groups
 
   validates :title, presence: true
   validates :query, presence: true
@@ -121,6 +60,6 @@ class PrometheusMetric < ApplicationRecord
   private
 
   def group_details(group)
-    GROUP_DETAILS.fetch(group.to_sym)
+    PrometheusMetricEnums.group_details.fetch(group.to_sym)
   end
 end
diff --git a/app/models/prometheus_metric_enums.rb b/app/models/prometheus_metric_enums.rb
new file mode 100644
index 00000000000..6cb22cc69cd
--- /dev/null
+++ b/app/models/prometheus_metric_enums.rb
@@ -0,0 +1,70 @@
+# frozen_string_literal: true
+
+module PrometheusMetricEnums
+  def self.groups
+    {
+      # built-in groups
+      nginx_ingress_vts: -1,
+      ha_proxy: -2,
+      aws_elb: -3,
+      nginx: -4,
+      kubernetes: -5,
+      nginx_ingress: -6,
+
+      # custom/user groups
+      business: 0,
+      response: 1,
+      system: 2
+    }
+  end
+
+  def self.group_details
+    {
+      # built-in groups
+      nginx_ingress_vts: {
+        group_title: _('Response metrics (NGINX Ingress VTS)'),
+        required_metrics: %w(nginx_upstream_responses_total nginx_upstream_response_msecs_avg),
+        priority: 10
+      }.freeze,
+      nginx_ingress: {
+        group_title: _('Response metrics (NGINX Ingress)'),
+        required_metrics: %w(nginx_ingress_controller_requests nginx_ingress_controller_ingress_upstream_latency_seconds_sum),
+        priority: 10
+      }.freeze,
+      ha_proxy: {
+        group_title: _('Response metrics (HA Proxy)'),
+        required_metrics: %w(haproxy_frontend_http_requests_total haproxy_frontend_http_responses_total),
+        priority: 10
+      }.freeze,
+      aws_elb: {
+        group_title: _('Response metrics (AWS ELB)'),
+        required_metrics: %w(aws_elb_request_count_sum aws_elb_latency_average aws_elb_httpcode_backend_5_xx_sum),
+        priority: 10
+      }.freeze,
+      nginx: {
+        group_title: _('Response metrics (NGINX)'),
+        required_metrics: %w(nginx_server_requests nginx_server_requestMsec),
+        priority: 10
+      }.freeze,
+      kubernetes: {
+        group_title: _('System metrics (Kubernetes)'),
+        required_metrics: %w(container_memory_usage_bytes container_cpu_usage_seconds_total),
+        priority: 5
+      }.freeze,
+
+      # custom/user groups
+      business: {
+        group_title: _('Business metrics (Custom)'),
+        priority: 0
+      }.freeze,
+      response: {
+        group_title: _('Response metrics (Custom)'),
+      priority: -5
+      }.freeze,
+      system: {
+        group_title: _('System metrics (Custom)'),
+        priority: -10
+      }.freeze
+    }.freeze
+  end
+end