fix(log_to_metric transform): Use correct keys for histogram/summary

[jblazquez]

Summary

This PR fixes log_to_metric transform to correctly handle metrics with a value type of MetricValue::AggregatedHistogram or MetricValue::AggregatedSummary.

See #24393

Vector configuration

[sources.opentelemetry]
type = "opentelemetry"
grpc.address = "0.0.0.0:4317"
http.address = "0.0.0.0:4318"

[transforms.my_metric_to_log]
type = "metric_to_log"
inputs = ["opentelemetry.metrics"]

[transforms.my_log_to_metric]
type = "log_to_metric"
inputs = [ "my_metric_to_log" ]
all_metrics = true
metrics = []

How did you test this PR?

1. Set up a graph as shown above.
2. Posted an OTEL Summary metric.

Change Type

• Bug fix
• New feature
• Non-functional (chore, refactoring, docs)
• Performance

Is this a breaking change?

• Yes
• No

Does this PR include user facing changes?

• Yes. Please add a changelog fragment based on our guidelines.
• No. A maintainer will apply the no-changelog label to this PR.

References

• Closes: log_to_metric: Histogram and summary metrics are converted incorrectly #24393

[jblazquez]

@pront Sorry for the direct ping, but this PR has been open for 3 weeks and you were the last one to modify this file, so I was hoping someone could take a look. Thanks!

[bruceg]

I've searched the commit history for this transform, and it has always used these names, so this fix looks correct to me. It would be ideal to have a combined metric_to_log => log_to_metric test, preferably using proptest, to fully validate this, but that may be a little beyond the scope of this PR.

[jblazquez]

Thanks Bruce. I did look into what would be involved in writing an end-to-end test but I didn't see any existing examples of that for this area of the code and felt it would increase the scope of the work quite a bit to figure that out.

[thomasqueirozb]

Thanks!