MP Data source: cannot override using environment variables

[tomas-langer]

Environment Details

• Helidon Version: 1.4.1
• Helidon MP

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Problem Description

When using CDI integration for data sources, we cannot override some settings using environment variables.

This is most likely caused by approach (such as in AbstractDataSourceExtension line 312) where we iterate through config sources instead of getting the value from config.

This approach may miss environment variable rules.

[ljnelson]

I'll take a look. Related: eclipse/microprofile-config#431 (comment)

[ljnelson]

@tomas-langer Looping back to this: is it your opinion that environment variable substitution rules should be housed outside of individual ConfigSources?

[tomas-langer]

@ljnelson - yes, this is done by the environment variable config source (and if you disable it, it should not happen). This also depends on order of config sources (so if your file source is before environment variables source, these rules will not trigger.

The method to get config sources is not intended for obtaining properties. You should always use methods on Config to follow the spec (otherwise you may get values from the wrong place)

[ljnelson]

Do you know offhand if, in our implementation, the requirement that the set of property names returned by Config#getPropertyNames() be equal to the union of the sets of property names returned by each installed ConfigSource is honored? It would seem if environment variables are aliased based on, among other things, the order of installed ConfigSources this would not be the case.

[ljnelson]

Whoops; never closed this; fixed back in September with #2322