make spring boot honor the standard environment variables for maps

[zeitlinger]

Fixes #10959

[jeanbisutti]

The map properties defined with an environment variable seems to take precedence over the map properties defined from a .properties / .yml file? It may be worth to document this in the next release.

[zeitlinger]

The map properties defined with an environment variable seems to take precedence over the map properties defined from a .properties / .yml file? It may be worth to document this in the next release.

Spring also gives precedence to environment variables, so I think spring users will expect that.

[jeanbisutti]

Spring also gives precedence to environment variables, so I think spring users will expect that.

The possibility of overriding some map values with an environment variable could be documented.

[zeitlinger]

Spring also gives precedence to environment variables, so I think spring users will expect that.

The possibility of overriding some map values with an environment variable could be documented.

I'd argue this is standard spring behavior, but I'm happy to point that out in the docs.

I'll link the PR here once done.

[zeitlinger]

I'll link the PR here once done.

open-telemetry/opentelemetry.io#4241

[trask]

the env var mapping makes me a little nervous since some otel resource attribute names include underscores

but I think we can argue that this is just a spring configuration feature(?)

[zeitlinger]

I can't follow - what are you nervous about? Maybe an example would help.

[trask]

some OTel resource attributes have underscores in them, and so it's not clear to me how these would work with env vars, e.g. does OTEL_RESOURCE_ATTRIBUTES_X_Y_Z correspond to resource attribute x.y.z, x.y_z, x_y.z, or x_y_z?

[zeitlinger]

oh, now I get it!

Based on that, I'd say:

• OTEL_RESOURCE_ATTRIBUTES_X_Y_Z should only be used to update an x.y.z or x_y_z that you have defined in application.yaml
• use OTEL_RESOURCE_ATTRIBUTES if you want to introduce new resource attributes

I think open-telemetry/opentelemetry.io#4241 is the right place to elaborate on this distinction.

[zeitlinger]

BTW, OTEL_RESOURCE_ATTRIBUTES_X_Y_Z results in x.y.z - which is indeed a spring boot feature.

[trask]

OTEL_RESOURCE_ATTRIBUTES_X_Y_Z should only be used to update an x.y.z or x_y_z that you have defined in application.yaml

oh, so it will auto-match if you have something matching already defined in application.yaml?

[zeitlinger]

Yes, it will auto match.