Use new boot ConfigData framework

[spencergibb]

Bootstrap is now opt-in.

See #608 for original motivation.

Remaining issues

• documentation updates.
• remove org.springframework.boot classes that are hacks
• fix FIXME: legacy issues. Mostly disabled tests.
• Deprecate bootstrap? make bootsrap opt-in

[spencergibb]

If you review post-merge, not a problem, I can address issues later since this is just a milestone.

[dzou]

@spencergibb - Hey we have a library which provides a custom property source for bootstrap configuration when users add our starter dependency to their project.

Is bootstrap property sources being deprecated or is there an alternate way to access this feature? We are also wondering if we should instruct users that they should add spring.config.use-legacy-processing=true to their application.properties now or if we might be able to set the property to true in our starter dependency by default somehow.

[ruben056]

Because bootstrapping is now disabled by default, my client no longer connects to the config server (bootstrap properties with config server uri are no longer read).
Adding: "spring.cloud.bootstrap.enabled=true" to the application.properties does not help. When this property is evaluated (BootstrapApplicationListener.onApplicationEvent), using "Environment.getProperty()", it is always empty...
Same for property "spring.config.use-legacy-processing".
Putting these properties in bootstrap.properties does not make sense because it will not be read, but putting them in application.properties also does not work, what should be done here?
Also I see there is a way of bootstrapping if the "org.springframework.cloud.bootstrap.marker.Marker" class is present, but it is not in the dependencies I have... (are you supposed to create it yourself?)

What is they new/correct way to have the client now about and connect to the config server after these changes?
I used the spring initializr to create the project with spring boot 2.4.0 (gradle). Only dependency was the "spring could config client", which was version "2020.0.0-M5".

[ryanjbaxter]

@ruben056 see the documentation

https://docs.spring.io/spring-cloud-config/docs/3.0.0-M5/reference/html/#config-first-bootstrap

It must be set as a System Property or environment variable.

[ruben056]

@ryanjbaxter Thx for the info, I was looking at the "older" docs I guess (https://cloud.spring.io/spring-cloud-config/multi/multi__spring_cloud_config_client.html)

[dzou]

@ruben056 - I think instead of setting the properties you can try using the new spring-cloud-starter-bootstrap to enable bootstrap; see: https://github.com/spring-cloud/spring-cloud-release/wiki/Spring-Cloud-2020.0-Release-Notes#breaking-changes

Adding this dependency to your project should have the equivalent effect of using spring.config.use-legacy-processing. I think for most applications its not practical to use the system property/environment variable route.

I think the "preferred" style is to migrate to the new spring.config.import style that is also discussed in the link. Think this should be in the new docs for config server.