add file descriptor metrics

[xiangtianyu]

related to #9340 Add file descriptor metrics to agent (support openj9)

[breedx-splk]

@xiangtianyu are you able to still take a look at this? Thanks!

[xiangtianyu]

@xiangtianyu are you able to still take a look at this? Thanks!

Nobody response my issue open-telemetry/semantic-conventions#1275 . Is there any update about the metrics specification?

[trask]

@xiangtianyu are you able to still take a look at this? Thanks!

Nobody response my issue open-telemetry/semantic-conventions#1275 . Is there any update about the metrics specification?

hi @xiangtianyu! that's ok, just add a comment in the code pointing to that semantic convention issue, and we can still merge the PR because it's under "experimental" metrics anyways

[xiangtianyu]

I've add comments, please take a look @breedx-splk @trask @laurit

[laurit]

Since this name isn't exactly the same as process.open_file_descriptors that is used by the host metric receiver we might as well go with a different name. I think it would be best to discuss these names and descriptions at the SIG meeting.

[xiangtianyu]

Ok, how can i propose this as a topic?

[trask]

based on https://github.com/open-telemetry/semantic-conventions/pull/1618/files

as a working group we believe it is important that process namespace and runtime namespace metrics remain separate, because process metrics are meant to represent an OS-level process as the instrumentation source, whereas runtime metrics represent the language runtime as the instrumentation source.

I'd suggest using jvm.open_file_descriptor.count

[laurit]

@trask do you also have suggestions for the metric descriptions and unit. Currently the unit is {count}.

[trask]

good catch: open-telemetry/semantic-conventions#1662

[trask]

for description, I think we can use

Number of file descriptors in use by the process.

from https://github.com/open-telemetry/semantic-conventions/blob/373a69574ec9605895102205d561b2476972e20c/model/process/metrics.yaml#L82

[trask]

based on https://github.com/open-telemetry/semantic-conventions/pull/1618/files

as a working group we believe it is important that process namespace and runtime namespace metrics remain separate, because process metrics are meant to represent an OS-level process as the instrumentation source, whereas runtime metrics represent the language runtime as the instrumentation source.

I'd suggest using jvm.open_file_descriptor.count

[jaydeluca]

it looks like some progress was made in semconv in this area:
open-telemetry/semantic-conventions#2139

[xiangtianyu]

it looks like some progress was made in semconv in this area: open-telemetry/semantic-conventions#2139

You are right, but it seems that someone has already implemented this metric

opentelemetry-java-instrumentation/instrumentation/runtime-telemetry/runtime-telemetry-java8/library/src/main/java/io/opentelemetry/instrumentation/runtimemetrics/java8/internal/ExperimentalFileDescriptor.java

Line 46 in cb6abd2

.upDownCounterBuilder("jvm.file_descriptor.count")

[trask]

@xiangtianyu should we close this PR then?

[github-actions]

This PR has been labeled as stale due to lack of activity and needing author feedback. It will be automatically closed if there is no further activity over the next 7 days.