[Feature]: Add Metrics Storage to StorageCapabilities

[aaryan359]

Requirement

As a Jaeger operator / Jaeger contributor
I want StorageCapabilities to explicitly expose whether metrics storage is supported
so that Jaeger Query and other components can reliably detect metrics support and enable/disable features accordingly.

Problem

Currently, StorageCapabilities does not include any field related to metrics storage.
There is even a TODO comment in the code:

// TODO: Maybe add metrics Storage here

Because of this:

• Components cannot reliably determine whether metrics storage is available
• Feature detection has to rely on assumptions or indirect checks
• Capability reporting is incomplete and may cause confusion for users and developers
• This limits extensibility and makes future metrics-related features harder to implement cleanly.

Proposal

Add a new field to StorageCapabilities, for example:

MetricsStorage bool json:"metricsStorage"

• Populate this field wherever StorageCapabilities is constructed
• Ensure the field is included in JSON responses
• Add unit tests to verify correct behavior
• This change would improve capability reporting without altering existing behavior.

Open questions

1. Should MetricsStorage be derived automatically from the configured storage factory?
2. Are there other capability flags that should be added alongside metrics support?

[aaryan359]

@yurishkuro @jkowall
Hi! I noticed the TODO about adding metrics storage to StorageCapabilities.

I wanted to check with you first, is this something that is still needed/makes sense to add?
If yes, I’d be happy to work on implementing it.

Thanks!