YAML anchors and refs in DW config

[Tommy Becker]

Does anyone have an example of YAML anchors/references actually working in a Dropwizard app? We have a couple of config values that are duplicated in a few places in the config, and I would very much like to use anchors/refs to deduplicate it. From what little I have been able to find it seems like it should work, but for the life of me I can't get it to.  I've annotated with @JsonIdentityInfo, and Jackson seems to recognize the anchors in that it strips them out of the config, but the references are not replaced properly, "*foo" gets replaced by simply "foo" for example. Any ideas?

[Christopher Currie]

You might try isolating what you're trying to do into a test case that uses Jackson and its YAML parser directly, without Dropwizard in the way, and if you can reproduce it there, asking on the Jackson User list: https://groups.google.com/d/forum/jackson-user

HTH,

Christopher

On Mon, Jun 19, 2017 at 7:30 AM, Tommy Becker <twbe...@gmail.com> wrote:

Does anyone have an example of YAML anchors/references actually working in a Dropwizard app? We have a couple of config values that are duplicated in a few places in the config, and I would very much like to use anchors/refs to deduplicate it. From what little I have been able to find it seems like it should work, but for the life of me I can't get it to.  I've annotated with @JsonIdentityInfo, and Jackson seems to recognize the anchors in that it strips them out of the config, but the references are not replaced properly, "*foo" gets replaced by simply "foo" for example. Any ideas?

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[Tatu Saloranta]

Anchors are supported to some degree, but only for cases where Object Id handling is explicitly specified for value type with `@JsonIdentityInfo`, and I don't think this is done for most config values for dropwizard configuration.

Problem here is that enabling identity also requires specification of an id property for values; if such a property exists, fine, if not, one would need to be added.

General purpose transparent resolution of anchors/references is not supported by Jackson YAML module.

You could probably implement a pre-processing step to do expansion first, then feeding resulting "flattened" input back to dropwizard.

-+ Tatu +-

On Mon, Jun 19, 2017 at 7:30 AM, Tommy Becker <twbe...@gmail.com> wrote:

Does anyone have an example of YAML anchors/references actually working in a Dropwizard app? We have a couple of config values that are duplicated in a few places in the config, and I would very much like to use anchors/refs to deduplicate it. From what little I have been able to find it seems like it should work, but for the life of me I can't get it to.  I've annotated with @JsonIdentityInfo, and Jackson seems to recognize the anchors in that it strips them out of the config, but the references are not replaced properly, "*foo" gets replaced by simply "foo" for example. Any ideas?

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