Merge branch 'system-info' into 'master'

Show basic system info on admin panel. Closes #18886

![Screen_Shot_2016-06-23_at_10.57.07_AM](/uploads/df33bc3dc36ceaf86f5e479ca15b83f3/Screen_Shot_2016-06-23_at_10.57.07_AM.png)

See merge request !4858

CHANGELOG

@@ -17,6 +17,7 @@ v 8.10.0 (unreleased)
   - Remove unused front-end variable -> default_issues_tracker
   - Add API endpoint for a group issues !4520 (mahcsig)
   - Allow [ci skip] to be in any case and allow [skip ci]. !4785 (simon_w)
+  - Add basic system information like memory and disk usage to the admin panel
 v 8.9.3 (unreleased)
   - Decreased min width of screen to 1280px for pinned sidebar

Gemfile

@@ -346,3 +346,6 @@ gem "paranoia", "~> 2.0"
 # Health check
 gem 'health_check', '~> 1.5.1'
+
+# System information
+gem 'vmstat', '~> 2.1.0'

Gemfile.lock

@@ -780,6 +780,7 @@ GEM
       coercible (~> 1.0)
       descendants_tracker (~> 0.0, >= 0.0.3)
       equalizer (~> 0.0, >= 0.0.9)
+    vmstat (2.1.0)
     warden (1.2.6)
       rack (>= 1.0)
     web-console (2.3.0)
@@ -984,6 +985,7 @@ DEPENDENCIES
   unicorn-worker-killer (~> 0.4.2)
   version_sorter (~> 2.0.0)
   virtus (~> 1.0.1)
+  vmstat (~> 2.1.0)
   web-console (~> 2.0)
   webmock (~> 1.21.0)
   wikicloth (= 0.8.1)

app/controllers/admin/system_info_controller.rb

+class Admin::SystemInfoController < Admin::ApplicationController
+  def show
+    system_info = Vmstat.snapshot
+
+    @cpus = system_info.cpus.length
+
+    @mem_used = system_info.memory.active_bytes
+    @mem_total = system_info.memory.total_bytes
+
+    @disk_used = system_info.disks[0].used_bytes
+    @disk_total = system_info.disks[0].total_bytes
+  end
+end

app/views/admin/background_jobs/_head.html.haml

 .nav-links.sub-nav
   %ul{ class: (container_class) }
+    = nav_link(controller: :system_info) do
+      = link_to admin_system_info_path, title: 'System Info' do
+        %span
+          System Info
     = nav_link(controller: :background_jobs) do
       = link_to admin_background_jobs_path, title: 'Background Jobs' do
         %span

app/views/admin/system_info/show.html.haml

+- @no_container = true
+- page_title "System Info"
+= render 'admin/background_jobs/head'
+
+%div{ class: (container_class) }
+  .prepend-top-default
+  .row
+    .col-sm-4
+      .light-well
+        %h4 CPU
+        .data
+          %h1= "#{@cpus} cores"
+    .col-sm-4
+      .light-well
+        %h4 Memory
+        .data
+          %h1= "#{number_to_human_size(@mem_used)} / #{number_to_human_size(@mem_total)}"
+    .col-sm-4
+      .light-well
+        %h4 Disk
+        .data
+          %h1= "#{number_to_human_size(@disk_used)} / #{number_to_human_size(@disk_total)}"

app/views/layouts/nav/_admin.html.haml

@@ -9,8 +9,8 @@
       = link_to admin_root_path, title: 'Overview', class: 'shortcuts-tree' do
         %span
           Overview
-    = nav_link(controller: %w(background_jobs logs health_check)) do
-      = link_to admin_background_jobs_path, title: 'Monitoring' do
+    = nav_link(controller: %w(system_info background_jobs logs health_check)) do
+      = link_to admin_system_info_path, title: 'Monitoring' do
         %span
           Monitoring
     = nav_link(controller: :broadcast_messages) do

config/routes.rb

@@ -280,6 +280,7 @@ Rails.application.routes.draw do
     resource :logs, only: [:show]
     resource :health_check, controller: 'health_check', only: [:show]
     resource :background_jobs, controller: 'background_jobs', only: [:show]
+    resource :system_info, controller: 'system_info', only: [:show]
     resources :namespaces, path: '/projects', constraints: { id: /[a-zA-Z.0-9_\-]+/ }, only: [] do
       root to: 'projects#index', as: :projects

spec/features/admin/admin_system_info_spec.rb

+require 'spec_helper'
+
+describe 'Admin System Info' do
+  before do
+    login_as :admin
+  end
+
+  describe 'GET /admin/system_info' do
+    it 'shows system info page' do
+      visit admin_system_info_path
+
+      expect(page).to have_content 'CPU'
+      expect(page).to have_content 'Memory'
+      expect(page).to have_content 'Disk'
+    end
+  end
+end