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Add exception message to logging when mapping fails due to an exception. #1248

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Merged
merged 4 commits into from
Jan 30, 2025
Merged

Add exception message to logging when mapping fails due to an exception. #1248

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eb7cf46
Add exception message to logging when mapping fails due to an exception.
JvE-iO Jan 29, 2025
eafc42b
Merge branch 'WireMock-Net:master' into patch-1
JvE-iO Jan 30, 2025
4951ef3
Revert "Add exception message to logging when mapping fails due to an…
JvE-iO Jan 30, 2025
2e247ff
Fix loggers with improved exception logging.
JvE-iO Jan 30, 2025
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2 changes: 1 addition & 1 deletion src/WireMock.Net/Owin/WireMockMiddleware.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -224,7 +224,7 @@ private async Task InvokeInternalAsync(IContext ctx)
}
catch (Exception ex)
{
_options.Logger.Error("HttpStatusCode set to 404 : No matching mapping found", ex);
_options.Logger.Error("HttpStatusCode set to 404 : 'No matching mapping found', due to exception '{0}'", ex);
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@StefH StefH Jan 29, 2025

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There is also Error method with an exception. Would that also work for you?

https://github.com/WireMock-Net/WireMock.Net/blob/master/src/WireMock.Net.Abstractions/Logging/IWireMockLogger.cs#L57

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@JvE-iO JvE-iO Jan 29, 2025

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I think that's already being used.

But WireMock.Net.Xunit.TestOutputHelperWireMockLogger.Error(string formatString, Exception exception) expects the formatString to have a placeholder for the exception message.

So it could also be fixed there. And in WireMock.Logging.WireMockConsoleLogger.Error(string formatString, Exception exception).

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@StefH StefH Jan 29, 2025 •
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OK I see, I did not detect this...

However, the reason that I did not expose the exception is because of security.

The best way to detect if a mapping is working correct or incorrect is looking at the logging.
https://github.com/WireMock-Net/WireMock.Net/wiki/Request-Matching-Tips

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@JvE-iO JvE-iO Jan 29, 2025

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Yes, that eventually told me it was a perfect match.

But that was immediately followed by a "HttpStatusCode set to 404 : No matching mapping found".

And then you're in limbo.
WireMock says it has a matching mapping and WireMock says no matching mapping was found. Nothing else is logged.

I finally figured out what was going on by creating and injecting a custom IWireMockLogger that does log exception messages.

Not logging the exception message for security reasons sounds strange to me. How would anyone know that an exception has occurred then? Also, your loggers do log all the exception messages when the type is AggregateException.

Anyway, even changing it to something like

_options.Logger.Error("Mapping failed due to unhandled exception. HttpStatusCode set to 404 : No matching mapping found", ex);

may help someone in the future a little bit.

Or maybe an exception occuring after a matching mapping has been found should not return a 404 with a "No matching mapping found" message. A 500 "something went wrong during the mapping" is probably more helpful.

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@StefH StefH Jan 29, 2025 •
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Maybe I miss the context, but this line (from the consolelogger.cs) does log the exception?
_options.Logger.Error("HttpStatusCode set to 404 : No matching mapping found", ex);

Example:

Error("HttpStatusCode set to 404 : No matching mapping found", new ArgumentNullException("abc"));

return;

void Error(string message, Exception exception)
{
    Console.WriteLine(Format("Error", $"{message} {{0}}", exception));

    if (exception is AggregateException ae)
    {
        ae.Handle(ex =>
        {
            Console.WriteLine(Format("Error", "Exception {0}", ex));
            return true;
        });
    }
}

static string Format(string level, string formatString, params object[] args)
{
    var message = args.Length > 0 ? string.Format(formatString, args) : formatString;

    return $"{DateTime.UtcNow} [{level}] : {message}";
}

Logging is:

1/29/2025 3:50:30 PM [Error] : HttpStatusCode set to 404 : No matching mapping found System.ArgumentNullException: Value cannot be null. (Parameter 'abc')

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@StefH StefH Jan 29, 2025

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But the TestOutputHelperWireMockLogger.cs could have an issue ?

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@JvE-iO JvE-iO Jan 30, 2025

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Aha, that clears up some of the confusion.
I'm not sure why, but when I asked Rider to show me the implementations of IWireMockLogger it "helpfully" included the decompiled version of a wiremock 1.5.1 nuget package I had on disk. There the WireMockConsoleLogger had the implementation without the placeholder for the exception message.

So we're left with just fixing these?

  • WireMock.Net.TUnit.TUnitWireMockLogger
  • WireMock.Net.Xunit.TestOutputHelperWireMockLogger
  • WireMock.Net.WebApplication.WireMockService.Logger

I've amended my PR.

Thank you for your patience in this :)


var notFoundResponse = ResponseMessageBuilder.Create(HttpStatusCode.NotFound, WireMockConstants.NoMatchingFound);
await _responseMapper.MapAsync(notFoundResponse, ctx.Response).ConfigureAwait(false);
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