How to set Map configuration properties using Environment Variables ?

[amoscatelli]

Hi everybody.

There are several Map configuration properties and, according to documentation (https://quarkus.io/guides/all-config), they can be set using Environment Variables.

I am trying to use QUARKUS_KUBERNETES_ENV_VARS.

Yet, setting an environment variable like this :

QUARKUS_KUBERNETES_ENV_VARS_TESTNAME=testvalue

doesn't seem to have any effect on my kubernates.yml.
This happens with both quarkus:dev Maven goal, or the quarkus:build Maven goal (using JIB).

At last, if I set (inside application.properties)

quarkus.kubernetes.env.vars.testname=testvalue

then the configuration is honored and I can see the environment variable inside my kubernates.yml.

This seems to happen with other Map configs, for example :

quarkus.container-image.labels-labels / QUARKUS_CONTAINER_IMAGE_LABELS

Other (non Map) environment variables are correctly working.

Can somebody confirm this is supposed to work ?
Please paste ANY example of environment variable configuration for any Map property, I could find none.

I already have different workarounds in mind, but I'd rather have this work just like this, so please help.

Thank you in advance !

[quarkus-bot[bot]]

/cc @Sgitario (kubernetes), @geoand (jib,kubernetes), @iocanel (kubernetes)

[geoand]

@radcortez can you shed some light on this? Perhaps we can also add an example to the config docs?

[radcortez]

Can you open a PR with it? Thank you :)

[amoscatelli]

Sorry but I can't.
The reason is I don't know why it works with this syntax.

QUARKUS_KUBERNETES_ENV_VARS__MP_JWT_VERIFY_ISSUER__ makes no sense since every _ should be a special character
I can't really explain the last __ to myself

I just found this by trial and error.

I think that some guy from microprofile config should explain this ...
I even tried to debug but I didn't solve the mistery

[amoscatelli]

And to tell the truth I don't really know if this is really a microprofile config thing, or this is some special rule/conversion coming from quarkus config extension

[radcortez]

Quarkus and SmallRye Config is well ahead of MP Config :) SmallRye Config defines additional rules to handle environment variables.

This is somehow a special case, because this Map contains composed keys to other configuration names. The issue is that we don't know if a composed dotted key is going to be used to map another property inside the configuration group or if it is part of the key itself. As an example:

quarkus.kubernetes.env.vars.var=value-> var=value -> This is ok because the key is a single name
quarkus.kubernetes.env.vars.my-env-var=value -> my-env-var=value -> Again, ok because the key is a single name
quarkus.kubernetes.env.vars.my.env.var=value -> EMPTY -> This is a composed key, but we don't know which part is the actual key an we can't assume
quarkus.kubernetes.env.vars."my.env.var"=value -> my.env.var=value -> Using quotes help us understand that my.env.var is the entire key, so it works.

In the case of Environment variables a double __ represents the .", so that is why you to surround the key with __ in an environment variable.

[amoscatelli]

ok thank you for the explanation !

[amoscatelli]

@radcortez ?

[radcortez]

Sorry, I was on PTO, but I'm glad you were able to figure it out :)