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Fixes issue when monitoring a process launched via the same command line #76965
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Tagging subscribers to this area: @tarekgh, @tommcdon, @pjanotti Issue DetailsFixes dotnet/diagnostics#3366. A NullReferenceException was being thrown and caught because the CommandHandler in MetricsEventSource was being referenced before being initialized. Now custom metrics are displayed when trying to monitor a process in the same command line. Here is example output for a simple application with a custom meter that displays random values:
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Can you include the callstack where the NullReferenceException occurs? A lot of the changes were swapping the Log property to a local parent field so does that also mean the static Log property was not initialized at that point? I want to understand what constraints we are working within :) |
@noahfalk we're trying to grab the original exception but running in to technical difficulties. The reason it fails is if you start a session before the runtime starts, you see the following scenario
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Got it. What if we did something like this?
private CommandHandler Handler {
get {
if(_handler == null) {
Interlocked.CompareExchange(ref _handler, new CommandHandler(this), null);
}
return handler;
}
public CommandHandler(MetricsEventSource parent) {
Parent = parent;
}
public MetricsEventSource Parent { get; }
// some code that needs to use parent
Parent.Error("Something bad happened"); |
Works for me |
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LGTM
Fixes dotnet/diagnostics#3366. A NullReferenceException was being thrown and caught because the CommandHandler in MetricsEventSource was being referenced before being initialized. Now custom metrics are displayed when trying to monitor a process in the same command line. Here is example output for a simple application with a custom meter that displays random values:
Running
dotnet-counters monitor --counters System.Runtime,demo_meter -- countersbug.exe
will now output:Running
dotnet-counters monitor --counters demo_meter -- countersbug.exe
will now output: