prometheusexporter: metrics plummeted without prior notification.

[shaj13]

Component(s)

No response

What happened?

Description

If the client sends, for instance, sum metrics without configuring AggregationTemporality, which is evidently incorrect, it leads to the otel prometheusexporter.Accumulator discarding those metrics without any prior notification.

example -> https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/exporter/prometheusexporter/accumulator.go#L168

Steps to Reproduce

send metrics without setting AggregationTemporality.

Expected Result

Warn/Info Log describes the dropped metrics including a reason.

Actual Result

The absence of logs necessitates debugging the entire metrics pipeline, encompassing otel and clients.

Collector version

latest

Environment information

Environment

OS: (e.g., "Ubuntu 20.04")
Compiler(if manually compiled): (e.g., "go 14.2")

OpenTelemetry Collector configuration

No response

Log output

No response

Additional context

No response

[github-actions]

Pinging code owners for exporter/prometheus: @Aneurysm9. See Adding Labels via Comments if you do not have permissions to add labels yourself.

[crobert-1]

I agree that it's good to log in this case to let users know why metrics are being dropped, but I would worry about log spam if it's anything more than debug. This isn't really an error or anything wrong in the collector, so it may be better suited to a lower log level.

If this log message occurs what can be done to resolve the issue? It seems like it would be useful the first time it's seen when debugging, but after that it would be known to the user and then just fill logs from then on.

[github-actions]

This issue has been inactive for 60 days. It will be closed in 60 days if there is no activity. To ping code owners by adding a component label, see Adding Labels via Comments, or if you are unsure of which component this issue relates to, please ping @open-telemetry/collector-contrib-triagers. If this issue is still relevant, please ping the code owners or leave a comment explaining why it is still relevant. Otherwise, please close it.

Pinging code owners:

• exporter/prometheus: @Aneurysm9

See Adding Labels via Comments if you do not have permissions to add labels yourself.

[github-actions]

This issue has been closed as inactive because it has been stale for 120 days with no activity.