Implement support for dynamic tags

[petethepig]

Other integrations have ways to set tags dynamically from the profiled application.

We'd love to be able to support dynamic tags in java for two main use cases:

Use case 1: Supporting Dynamic tags for user-defined scopes

Often users want to tag a region, namespace, pod, container, machine, etc and dynamic tags would allow them to do this.
e.g here's how it's done in go: https://github.com/pyroscope-io/pyroscope/blob/main/examples/golang-push/rideshare/utility/utility.go#L46-L57

And we then support using these tags to compare and calculate diffs between profiles. I.e. here we are showing the diff between the region tags:

• ride-sharing-app.cpu{region="us-west-1"}
• ride-sharing-app.cpu{region="eu-west-1"}

Comparing two tags

Diff between two tags

See here for interactive example

Use case 2: Supporting profile_id tag for profiling exemplars

We recently created a otelpyroscope package which is meant to link trace spans from a distributed tracing system (i.e. jaeger) to profiles

How this works is:

• when a span is created, we begin profiling in that thread and tag that profile with a corresponding profile_id
• the pyroscope agent then sends that profile to the server where it is stored in an exemplar-specific db (separate from other profiling data)
• If the profile_id tag value is stored in metadata people can then retrieve this via tracing UI's

i.e. in this image you can embed a profile for this particular span, because it was conveniently tagged as
pyroscope.profile.id = 840f2c4bd6e4a2c4

Reference:
OTEL issue about standardizing profile formats: open-telemetry/oteps#139
Async-profiler PR attempting to add (a type) of tag: async-profiler/async-profiler#576

[netamego]

Hi!!

Could be posible yo use labels/tags and app aggregation without modofing the source code of my app. I don't know if is feadible but would be great we could define tags/labels with an exported variable.

Thanks.

[Rperry2174]

Hi @netamego I'm going to go ahead and close this issue since this one is complete.

• Docs
• Examples

If you dont mind could you create a separate issue around using labels/tags in the way that you'd like (with an example of the use case)?