Github user cestella commented on a diff in the pull request:
https://github.com/apache/metron/pull/1021#discussion_r189900746
--- Diff:
metron-platform/metron-common/src/main/java/org/apache/metron/common/configuration/enrichment/handler/StellarConfig.java
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@@ -142,8 +143,14 @@ else if(kv.getValue() instanceof List) {
{
--- End diff --
Well, I added it because I came across it multiple times in data science
use-cases. Specifically, the way that we do model application via MaaS (and
other model applications) presumes that the user will filter just the fields
into the model, rather than having the model select it. This puts an undue
burden on the user as the model knows which fields it wants and the user may
not, so being able to pass the whole message lets the model do the decision. I
think that `_` is a natural way to do that. To be fair, also, this is a
capability inherent to the VariableResolver, not the grammar itself, which I
thought was reasonable. SOme variable resolvers won't support it and some will.
Thoughts?
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