Merge branch '21378-error-500-after-8-11-update-on-system-infos-page' into 'master'

Handle unavailable system info

## What does this MR do?

Handle the case where we can't get system info without blowing up. As this is the first tab in the monitoring section, it's difficult to get to the other tabs if this page throws a 500. Also be more specific about the info we want, so we don't fail on something we don't care about (like `/proc/net/dev`).

## Why was this MR needed?

grsecurity can prevent users from reading `/proc`, which is what Vmstat uses to find CPU and memory info.

## What are the relevant issue numbers?

Closes #21378.

See merge request !5989

CHANGELOG

@@ -11,6 +11,9 @@ v 8.11.2
   - Don't show resolve conflicts link before MR status is updated
   - Don't prevent viewing the MR when git refs for conflicts can't be found on disk
 
+v 8.11.3 (unreleased)
+  - Allow system info page to handle case where info is unavailable
+
 v 8.11.2 (unreleased)
   - Show "Create Merge Request" widget for push events to fork projects on the source project
 

Gemfile

@@ -349,5 +349,5 @@ gem 'paranoia', '~> 2.0'
 gem 'health_check', '~> 2.1.0'
 
 # System information
-gem 'vmstat', '~> 2.1.1'
+gem 'vmstat', '~> 2.2'
 gem 'sys-filesystem', '~> 1.1.6'

Gemfile.lock

@@ -772,7 +772,7 @@ GEM
       coercible (~> 1.0)
       descendants_tracker (~> 0.0, >= 0.0.3)
       equalizer (~> 0.0, >= 0.0.9)
-    vmstat (2.1.1)
+    vmstat (2.2.0)
     warden (1.2.6)
       rack (>= 1.0)
     web-console (2.3.0)
@@ -980,7 +980,7 @@ DEPENDENCIES
   unicorn-worker-killer (~> 0.4.2)
   version_sorter (~> 2.1.0)
   virtus (~> 1.0.1)
-  vmstat (~> 2.1.1)
+  vmstat (~> 2.2)
   web-console (~> 2.0)
   webmock (~> 1.21.0)
   wikicloth (= 0.8.1)

app/controllers/admin/system_info_controller.rb

@@ -29,7 +29,8 @@ class Admin::SystemInfoController < Admin::ApplicationController
   ]
 
   def show
-    system_info = Vmstat.snapshot
+    @cpus = Vmstat.cpu rescue nil
+    @memory = Vmstat.memory rescue nil
     mounts = Sys::Filesystem.mounts
 
     @disks = []
@@ -50,10 +51,5 @@ class Admin::SystemInfoController < Admin::ApplicationController
       rescue Sys::Filesystem::Error
       end
     end
-
-    @cpus = system_info.cpus.length
-
-    @mem_used = system_info.memory.active_bytes
-    @mem_total = system_info.memory.total_bytes
   end
 end

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

@@ -9,12 +9,20 @@
       .light-well
         %h4 CPU
         .data
-          %h1= "#{@cpus} cores"
+          - if @cpus
+            %h1= "#{@cpus.length} cores"
+          - else
+            = icon('warning', class: 'text-warning')
+            Unable to collect CPU info
     .col-sm-4
       .light-well
         %h4 Memory
         .data
-          %h1= "#{number_to_human_size(@mem_used)} / #{number_to_human_size(@mem_total)}"
+          - if @memory
+            %h1= "#{number_to_human_size(@memory.active_bytes)} / #{number_to_human_size(@memory.total_bytes)}"
+          - else
+            = icon('warning', class: 'text-warning')
+            Unable to collect memory info
     .col-sm-4
       .light-well
         %h4 Disks

spec/features/admin/admin_system_info_spec.rb

@@ -6,12 +6,49 @@ describe 'Admin System Info' do
   end
 
   describe 'GET /admin/system_info' do
+    let(:cpu) { double(:cpu, length: 2) }
+    let(:memory) { double(:memory, active_bytes: 4294967296, total_bytes: 17179869184) }
+
+    context 'when all info is available' do
+      before do
+        allow(Vmstat).to receive(:cpu).and_return(cpu)
+        allow(Vmstat).to receive(:memory).and_return(memory)
+        visit admin_system_info_path
+      end
+
       it 'shows system info page' do
+        expect(page).to have_content 'CPU 2 cores'
+        expect(page).to have_content 'Memory 4 GB / 16 GB'
+        expect(page).to have_content 'Disks'
+      end
+    end
+
+    context 'when CPU info is not available' do
+      before do
+        allow(Vmstat).to receive(:cpu).and_raise(Errno::ENOENT)
+        allow(Vmstat).to receive(:memory).and_return(memory)
         visit admin_system_info_path
+      end
+
+      it 'shows system info page with no CPU info' do
+        expect(page).to have_content 'CPU Unable to collect CPU info'
+        expect(page).to have_content 'Memory 4 GB / 16 GB'
+        expect(page).to have_content 'Disks'
+      end
+    end
 
-      expect(page).to have_content 'CPU'
-      expect(page).to have_content 'Memory'
+    context 'when memory info is not available' do
+      before do
+        allow(Vmstat).to receive(:cpu).and_return(cpu)
+        allow(Vmstat).to receive(:memory).and_raise(Errno::ENOENT)
+        visit admin_system_info_path
+      end
+
+      it 'shows system info page with no CPU info' do
+        expect(page).to have_content 'CPU 2 cores'
+        expect(page).to have_content 'Memory Unable to collect memory info'
         expect(page).to have_content 'Disks'
       end
     end
+  end
 end