FEATURE: basic disk space usage stats

app/assets/javascripts/admin/routes/admin-dashboard.js.es6

@@ -24,7 +24,7 @@ export default Discourse.Route.extend({
           c.set('top_referrers', topReferrers);
         }
 
-        ['admins', 'moderators', 'blocked', 'suspended', 'top_traffic_sources', 'top_referred_topics', 'updated_at'].forEach(function(x) {
+        ['disk_space','admins', 'moderators', 'blocked', 'suspended', 'top_traffic_sources', 'top_referred_topics', 'updated_at'].forEach(function(x) {
           c.set(x, d[x]);
         });
 

app/assets/javascripts/admin/templates/dashboard.hbs

@@ -100,6 +100,28 @@
       {{/unless}}
     </table>
   </div>
+  <div class="dashboard-stats">
+    <table class="table table-condensed table-hover">
+      <thead>
+        <tr>
+          <th>&nbsp;</th>
+          <th></th>
+          <th></th>
+          <th></th>
+        </tr>
+      </thead>
+      <tbody>
+          {{#unless loading}}
+          <tr>
+            <td>{{i18n 'admin.dashboard.uploads'}}</td>
+            <td>{{disk_space.uploads_used}} ({{i18n 'admin.dashboard.space_free' size=disk_space.uploads_free}})</td>
+            <td>{{i18n 'admin.dashboard.backups'}}</td>
+            <td>{{disk_space.backups_used}} ({{i18n 'admin.dashboard.space_free' size=disk_space.backups_free}} free)</td>
+          </tr>
+          {{/unless}}
+      </tbody>
+    </table>
+  </div>
 </div>
 
 <div class="dashboard-right">

app/controllers/admin/dashboard_controller.rb

@@ -1,7 +1,10 @@
+require 'disk_space'
 class Admin::DashboardController < Admin::AdminController
   def index
     dashboard_data = AdminDashboardData.fetch_cached_stats || Jobs::DashboardStats.new.execute({})
     dashboard_data.merge!({version_check: DiscourseUpdates.check_version.as_json}) if SiteSetting.version_checks?
+
+    dashboard_data[:disk_space] = DiskSpace.cached_stats
     render json: dashboard_data
   end
 

config/locales/client.en.yml

@@ -1531,6 +1531,9 @@ en:
         suspended: 'Suspended:'
         private_messages_short: "PMs"
         private_messages_title: "Private Messages"
+        space_free: "{{size}} free"
+        uploads: "uploads"
+        backups: "backups"
 
         reports:
           today: "Today"

lib/disk_space.rb

@@ -0,0 +1,65 @@
+class DiskSpace
+
+  extend ActionView::Helpers::NumberHelper
+
+  def self.uploads_used_bytes
+    used(uploads_path)
+  end
+
+  def self.uploads_free_bytes
+    free(uploads_path)
+  end
+
+  def self.backups_used_bytes
+    used(backups_path)
+  end
+
+  def self.backups_free_bytes
+    free(backups_path)
+  end
+
+  def self.backups_path
+    Backup.base_directory
+  end
+
+  def self.uploads_path
+    "#{Rails.root}/public/uploads/#{RailsMultisite::ConnectionManagement.current_db}"
+  end
+
+  def self.stats
+    {
+      uploads_used: number_to_human_size(uploads_used_bytes),
+      uploads_free: number_to_human_size(uploads_free_bytes),
+      backups_used: number_to_human_size(backups_used_bytes),
+      backups_free: number_to_human_size(backups_free_bytes)
+    }
+  end
+
+  def self.cached_stats
+    stats = $redis.get('disk_space_stats')
+    updated_at = $redis.get('disk_space_stats_updated')
+
+    unless updated_at && (Time.now.to_i - updated_at.to_i) < 30.minutes
+      Scheduler::Defer.later "updated stats" do
+        $redis.set('disk_space_stats_updated', Time.now.to_i)
+        $redis.set('disk_space_stats', self.stats.to_json)
+      end
+    end
+
+    if stats
+      JSON.parse(stats)
+    end
+
+  end
+
+  protected
+
+  def self.free(path)
+    `df -Pk #{path} | awk 'NR==2 {print $4 * 1024;}'`.to_i
+  end
+
+  def self.used(path)
+    `du -s #{path}`.to_i * 1024
+  end
+
+end