Azure App Service: using PerformanceCounters - azure

Question

I am trying to setup my Azure Web App to include the use of a third party software, which seems to require access to PerformanceCounters. Locally this works fine, but when I run it in Azure I get the following error:
[UnauthorizedAccessException: Access to the registry key 'Global' is denied.]
Microsoft.Win32.RegistryKey.Win32Error(Int32 errorCode, String str) +5230217
Microsoft.Win32.RegistryKey.InternalGetValue(String name, Object defaultValue, Boolean doNotExpand, Boolean checkSecurity) [phone]
Microsoft.Win32.RegistryKey.GetValue(String name) +40
System.Diagnostics.PerformanceMonitor.GetData(String item) +102
System.Diagnostics.PerformanceCounterLib.GetPerformanceData(String item) +186
System.Diagnostics.PerformanceCounterLib.get_CategoryTable() +105
System.Diagnostics.PerformanceCounterLib.GetCategorySample(String category) +17
System.Diagnostics.PerformanceCounterLib.GetCategorySample(String machine, String category) +61
System.Diagnostics.PerformanceCounterCategory.GetCounterInstances(String categoryName, String machineName) +70
System.Diagnostics.PerformanceCounterCategory.GetInstanceNames() +25
According to this answer, I should configure IIS to allow access to the app pool/user, but I don't think that is possible for a Azure Web App. Is there a way to get performance counters working in my situation?

Answer 1

On Windows, Performance Counters are accessible through WMI:
https://msdn.microsoft.com/en-us/library/aa392397(v=vs.85).aspx
WMI is restricted in the App Service sandbox.
From https://github.com/projectkudu/kudu/wiki/Azure-Web-App-sandbox#access-to-out-of-process-com-servers:
Access to out-of-process COM servers
Windows Servers have a bunch of COM servers configured and available for consumption by default; however the sandbox prevents access to all out-of-proc COM servers. For example, a sandboxed application cannot call into WMI, or into MSIServer.
From Kudu:
PS D:\home> Get-Counter -Counter "\processor(_total)\% processor time"
Get-Counter : The specified object was not found on the computer.
PS D:\home> Get-WmiObject -Class WIN32_OperatingSystem
Get-WmiObject : Access is denied. (Exception from HRESULT: 0x80070005
(E_ACCESSDENIED))
If you absolutely have to use the 3rd party software, look at Azure Cloud Services (with a Web Role). You have full control over the OS there while still being PaaS.