Masking and formatting using annotations

[pecigonzalo]

Hi! Im looking to implement masking of some fields for Arguments and MDC given the origin object annotations. Something along the lines of what is decribed in https://gkovan.medium.com/pci-and-pii-compliance-when-logging-data-in-digital-transformation-projects-7739bab159a6

I've gave it a go using custom Providers and the likes, but it seems that from the provider perspective I can only access maps/strings, but not the original objects, so I can do custom actions based on the annotations.

This would be my sample data class and annotation

@Target(
    AnnotationTarget.FIELD,
)
@Retention(AnnotationRetention.RUNTIME)
@MustBeDocumented
annotation class Mask(val mask: String = "*****")

@Serializable
data class Customer(
    val id: String,
    val firstName: String,
    val lastName: String,
    @Mask() val email: String
)

Any ideas or pointers? Anyone has implemented something similar?

[brenuart]

Hi @pecigonzalo ,

That would be a nice feature indeed. A few questions tho...
The behaviour of the @Mask annotation is quite obvious when put on a String field. But what would you expect in the following scenarios:

• Annotation on a Collection

@Mask Collection<String> collectionOfString;

Would you expect the entire collection field to be masked - similar to the current masking behaviour when the path points to the field holding the collection? Example:

"collectionOfString": "****"

Or maybe the @Mask annotation should accept a path pattern that would be evaluated starting at the annotated field? The following example would then mask only the second entry of the collection (index is 0 based):

@Mask(path="1") Collection<String> collectionOfString;

This would produce a JSON similar to:

"collectionOfString" : [
   "first string",
   "****",
   "third string"
]

• Annotation on a Pojo

Same question when the annotation is put on a field holding a Pojo..

@Mask Pojo mojo;

[pecigonzalo]

Would you expect the entire collection field to be masked

I think this would be a good option yeah. It could be interesting to mask on each item (eg a list of email), but this might prove a bit complex both implementation wise and processing wise. If we assume a collection is of a type of something, we most likely want all of the collection masked in the same fashion, so @Mask(path="1") would not be my choice. I would rather mask all the items in the same way, or just place a string as in your example.

Annotation on a Pojo

I would not traverse the Pojo, if the Pojo needs masking the it should be defined in the data class of that pojo.

PS: Sorry for the long wait here!