Add a host resource detector

[pyohannes]

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Fixes #5398

This PR adds a resource detector for physical hosts which sets values according to semantic conventions for host resources:

• host.arch
• host.id
• host.name
• host.ip
• host.mac

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 93.84615% with 4 lines in your changes are missing coverage. Please review.

Project coverage is 62.5%. Comparing base (30ed923) to head (f585990).

Additional details and impacted files

@@           Coverage Diff           @@
##            main   #5399     +/-   ##
=======================================
+ Coverage   62.3%   62.5%   +0.1%     
=======================================
  Files        189     191      +2     
  Lines      11575   11640     +65     
=======================================
+ Hits        7221    7282     +61     
- Misses      4145    4147      +2     
- Partials     209     211      +2     

Files	Coverage Δ
detectors/host/host.go	96.6% <96.6%> (ø)
detectors/host/host_id_linux.go	60.0% <60.0%> (ø)

[MrAlias]

This seems duplicative of WithHost. Why not update that option?

[pyohannes]

This seems duplicative of WithHost. Why not update that option?

Indeed it is duplicative.

@MrAlias Do you think it a feasible option to populate host.arch via WithHost, and add additional WithHostIP and WithHostMAC to opt into host.ip and host.mac (all implemented in the SDK)?

[MrAlias]

Taking a look at the host semantic conventions, it looks like they are all experimental (even host.name :grimacing:).

I think in the long term we want to make the WithHost option include all the recommended/required stable semantic conventions for a host. But in the interim, having a detector here is probably the correct approach.

I think this PR is the correct approach. I'll plan to review.

[pyohannes]

Missing support for BSD: https://github.com/open-telemetry/opentelemetry-go/blob/main/sdk/resource/host_id_bsd.go Missing fallback when the host system is not supported for the host ID: https://github.com/open-telemetry/opentelemetry-go/blob/main/sdk/resource/host_id_unsupported.go

Thanks @MrAlias, this should be ready for another review.

[dashpole]

But in the interim, having a detector here is probably the correct approach.

@MrAlias Should we use feature environment variables instead of a new detector module?

[MrAlias]

But in the interim, having a detector here is probably the correct approach.

@MrAlias Should we use feature environment variables instead of a new detector module?

That's a good idea.

[MrAlias]

But in the interim, having a detector here is probably the correct approach.

@MrAlias Should we use feature environment variables instead of a new detector module?

That's a good idea.

I've added this to the SIG meeting agenda to discuss.

[MrAlias]

@pyohannes can this be closed? We plan to move this into this (behind the experimental envar), right?