Prometheus Exporer Dupplicate Tag error_type

[vinh3c]

Bug Report

• OpenTelemetry.Exporter.Prometheus.AspNetCore 1.7.0-rc.1
• net8.0

Symptom

=> Prometheus Pull Agent
label name "error_type" is not unique: invalid sample

When aspnetcore host nginx, Request has a Application Exception, after that the request connection is closed => aspnet core add more than one error tag

Reproduce

var tagsFeature = context
      .Features
      .Get<IHttpMetricsTagsFeature>();
tagsFeature.Tags.Add("error.type", "System.InvalidOperationException")
tagsFeature.Tags.Add("error.type", "MysqlConnector.MySqlException")

[madyar0v]

+1

[cijothomas]

Neither the OTel Metrics API (i.e Meter/instruments from DS), nor the OTel Metrics SDK performs de-duplication, as that will cause perf issues. However, exporters can do de-dup, if the backend it is exporting to cannot deal with duplicates.
We can treat this as a bug in Prometheus Exporter, and fix it.
Also need to check if OTLP exporter should also provide a feature to dedup on export.

[AlexBAV]

I've experienced the same problem.

For a web application running under IIS on Windows Server, after adding a second HTTPS binding, HTTPS redirection middleware starts generating exceptions for HTTP requests which results in duplicate error_type="System.InvalidOperationException", error_type="System.InvalidOperationException" items.

[hacst]

At first glance this looks very similar to a problem I have been encountering in conjunction with websockets. Imo the fact that AspNetCore itself duplicates this tag is something that should be fixed upstream, so I reported it there.

Now if a user themselves introduced tag duplication that would be a different story.

[reyang]

Imo the fact that AspNetCore itself duplicates this tag is something that should be fixed upstream, so I reported it there.

Now if a user themselves introduced tag duplication that would be a different story.

Closing this issue as there is no action item for OpenTelemetry.Exporter.Prometheus.AspNetCore.

[imclint21]

I got this error too

[imclint21]

Imo the fact that AspNetCore itself duplicates this tag is something that should be fixed upstream, so I reported it there.
Now if a user themselves introduced tag duplication that would be a different story.

Closing this issue as there is no action item for OpenTelemetry.Exporter.Prometheus.AspNetCore.

@reyang your exporter is not valid for Prometheus, so why close this issue?