Can't retrieve MemoryCache statistics using dotnet-counters

[georgesimeonov]

Is there an existing issue for this?

• I have searched the existing issues

Describe the bug

I'm using the examples provided in here and here for getting statistics out of an IMemoryCache. I'm doing everything as described and then trying to observe using dotnet-counters. Nothing is shown and the dotnet-counters command seems stuck on "Waiting for initial payload". I'm certainly not an expert on EventCounters and am not sure if this is actually a bug, but I can't see another fitting category to be honest.

P.S. I've already read through several issues (1, 2) on the topic as well as the eventcounters README, but still can't figure out what the problem is.

Expected Behavior

See the memory cache statistics as shown in the examples linked above.

Steps To Reproduce

The repro project: https://github.com/grott0/dotnet-repro.git

Exceptions (if any)

N/A

.NET Version

7.0.102

Anything else?

Visual Studio 2022 17.4.2

.NET SDK:
Version: 7.0.102
Commit: 4bbdd14480

Runtime Environment:
OS Name: Windows
OS Version: 10.0.19044
OS Platform: Windows
RID: win10-x64
Base Path: C:\Program Files\dotnet\sdk\7.0.102\

Host:
Version: 7.0.2
Architecture: x64
Commit: d037e07

.NET SDKs installed:
2.0.0 [C:\Program Files\dotnet\sdk]
2.1.3 [C:\Program Files\dotnet\sdk]
2.1.4 [C:\Program Files\dotnet\sdk]
2.1.100 [C:\Program Files\dotnet\sdk]
2.1.101 [C:\Program Files\dotnet\sdk]
2.1.102 [C:\Program Files\dotnet\sdk]
2.1.103 [C:\Program Files\dotnet\sdk]
2.1.104 [C:\Program Files\dotnet\sdk]
2.1.105 [C:\Program Files\dotnet\sdk]
2.1.200 [C:\Program Files\dotnet\sdk]
2.1.201 [C:\Program Files\dotnet\sdk]
2.1.202 [C:\Program Files\dotnet\sdk]
2.1.818 [C:\Program Files\dotnet\sdk]
2.2.110 [C:\Program Files\dotnet\sdk]
2.2.207 [C:\Program Files\dotnet\sdk]
3.0.100 [C:\Program Files\dotnet\sdk]
3.1.202 [C:\Program Files\dotnet\sdk]
3.1.426 [C:\Program Files\dotnet\sdk]
5.0.104 [C:\Program Files\dotnet\sdk]
5.0.303 [C:\Program Files\dotnet\sdk]
5.0.404 [C:\Program Files\dotnet\sdk]
5.0.408 [C:\Program Files\dotnet\sdk]
6.0.104 [C:\Program Files\dotnet\sdk]
6.0.113 [C:\Program Files\dotnet\sdk]
7.0.100 [C:\Program Files\dotnet\sdk]
7.0.102 [C:\Program Files\dotnet\sdk]

.NET runtimes installed:
Microsoft.AspNetCore.All 2.1.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.19 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.All 2.2.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.All]
Microsoft.AspNetCore.App 2.1.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.19 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 2.2.8 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.5 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.22 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.31 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 3.1.32 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.9 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 6.0.11 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 6.0.13 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 7.0.0 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.AspNetCore.App 7.0.2 [C:\Program Files\dotnet\shared\Microsoft.AspNetCore.App]
Microsoft.NETCore.App 2.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.0.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.0.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.0.6 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.0.7 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.0.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.13 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.19 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.1.30 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 2.2.8 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.5 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.22 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.31 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 3.1.32 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.9 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.13 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 6.0.11 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 6.0.13 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 7.0.0 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.NETCore.App 7.0.2 [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
Microsoft.WindowsDesktop.App 3.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 3.1.4 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 3.1.22 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 3.1.31 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 3.1.32 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 5.0.4 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 5.0.9 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 5.0.13 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 5.0.17 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 6.0.11 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 6.0.13 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 7.0.0 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]
Microsoft.WindowsDesktop.App 7.0.2 [C:\Program Files\dotnet\shared\Microsoft.WindowsDesktop.App]

Other architectures found:
arm64 [C:\Program Files\dotnet]
registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\arm64\InstallLocation]
x86 [C:\Program Files (x86)\dotnet]
registered at [HKLM\SOFTWARE\dotnet\Setup\InstalledVersions\x86\InstallLocation]

Environment variables:
Not set

global.json file:
Not found

Learn more:
https://aka.ms/dotnet/info

[BrennanConroy]

This looks like an issue for https://github.com/dotnet/diagnostics, please file an issue there.

[georgesimeonov]

A quick update. I don't think opening a new issue makes sense at this point, because I was able to display the statistics from the memory cache by simply creating a new singleton instance of the CachingEventSource class (from the the repro project). I would suggest someone update this gist from this example by explaining what needs to be done more elaborately.

[BrennanConroy]

cc @maryamariyan

[adityamandaleeka]

@tarekgh Not sure who the current owner is... can you help route this?

[tarekgh]

This is working as expected. Here is the code I used which produced the result in the picture:

    public class Program
    {
        static MemoryCache cache = new MemoryCache(new MemoryCacheOptions { TrackStatistics = true });
        static Meter s_meter = new Meter("Microsoft.Extensions.Caching.Memory.MemoryCache", "1.0.0");

        public static void Main(string[] args)
        {
            var cacheHitsMetrics = s_meter.CreateObservableGauge<long>("cache-entryCount", GetCacheEntryCount);

            // metrics callback for cache hits
            static IEnumerable<Measurement<long>> GetCacheEntryCount()
            {
                return new Measurement<long>[]
                {
                    // or measurements could be looped or read from a real queue somewhere:
                    new Measurement<long>(cache.GetCurrentStatistics()!.CurrentEntryCount, new KeyValuePair<string, object?>("CacheName", "cache"))
                };
            }

            Console.WriteLine($"run dotnet-counters monitor --process-id {Process.GetCurrentProcess().Id} --counters Microsoft.Extensions.Caching.Memory.MemoryCache --refresh-interval 1 ");
            Console.WriteLine($"Then press enter here.");
            Console.ReadKey(); // pause to get the process id and run dotnet-counters with that id

            for (int i = 0; i < 500; i++)
            {
                cache.Set("key" + i, "value" + i, new MemoryCacheEntryOptions { Size = i });
                Task.Delay(100).Wait();
                Console.WriteLine($"cache.GetCurrentStatistics()!.GetCacheEntryCount: {cache.GetCurrentStatistics()!.CurrentEntryCount}");
            }
          }
    }

I am closing the issue but feel free to send any questions if this still does not work for you.

[georgesimeonov]

@tarekgh Yeah, you're right. Doing this in a console app is not a problem. Try following the DI example for an ASP.NET Core app in the gist which I've linked in the previous comment. It won't work out of the box, you'll have to register a singleton instance of the CachingEventSource class in order for it to work. You can also check the repro app which I've provided in the post.

In summary, I don't think there's a problem with the implementation. It's more like a documentation issue.

[tarekgh]

@grott0 thanks for the feedback. Could you please send a PR suggesting the doc change?