Add telemetry instrumentation

[hrodmn]

It would be useful for titiler applications to be capable of sharing telemetry data so that application administrators can understand usage patterns and performance bottlenecks.

Here is an example of the type of insights users could get if we add telemetry capability

I have been experimenting with this in my local environment and have a proposal for a telemetry plan for titiler:

1. Add open-telemetry (and associated packages) to a new optional dependencies group in titiler.core
2. Add titiler.core.telemetry module with some convenience functions/decorators/context managers for adding telemetry to factory methods and specific operations.
   • loadable even if telemetry dependencies are not installed
3. Add telemetry decorators to important endpoints like /tile in titiler.core.factory.TilerFactory, titiler.mosaic.factory.MosaicTilerFactory, titiler.xarray.factory.TilerFactory
   • if telemetry is not enabled/installed, these are no-ops
4. Demonstrate how to enable telemetry export in titiler.application.main
5. Add telemetry instrumentation to downstream applications/packages (titiler-pgstac, titiler-cmr, etc)

@vincentsarago what do you think? Would you rather we add this type of functionality somewhere like titiler-pgstac first then bring it back to titiler.core later? cc @sharkinsspatial @abarciauskas-bgse

[abarciauskas-bgse]

Thank you for opening this discussion @hrodmn ! Very recently someone asked why visualization for a given dataset from titiler-cmr is so slow and it would be great to be able to easily provide a specific answer.

[vincentsarago]

Thanks for starting this @hrodmn

@vincentsarago what do you think? Would you rather we add this type of functionality somewhere like titiler-pgstac first then bring it back to titiler.core later? cc @sharkinsspatial @abarciauskas-bgse

I think it makes sense to start this in titiler.core 👍

Do you know the performance impact when telemetry is enabled?

[hrodmn]

Do you know the performance impact when telemetry is enabled?

I am not really sure what the performance impact will be, but I'll try to figure it out as I test the changes in #1171