How to combine 2 files and merge array while deduplicating on sub-key

[tcreese]

I'm trying to figure out how to merge two yaml files into one and combine the "rules" array but deduplicate items based on the identifier keeping the value in the host.yaml file.

global.yaml

mode: MONITOR
batch_size: 100
rules:
  - rule_type: SIGN
    policy: block
    identifier: itemA
    msg: block itemA
  - rule_type: SIGN
    policy: allow
    identifier: itemB
    msg: allow itemB

host.yaml

mode: WHITELIST
rules:
  - rule_type: SIGN
    policy: allow
    identifier: itemA
    msg: allow itemA

Desired Output

mode: WHITELIST
batch_size: 100
rules:
  - rule_type: SIGN
    policy: allow
    identifier: itemB
    msg: allow itemB
  - rule_type: SIGN
    policy: allow
    identifier: itemA
    msg: allow itemA

I've tried a couple of things but can't seem to figure out exactly what I'm trying to do.

[tcreese]

I was able to figure it out this way, but I'm not certain it will 100% prioritize the items found in the rules array of the host.yaml file.
yq ea '. as $item ireduce ({}; . *+ $item)' global.yaml test.yaml |\ yq ea '(((.rules | .[] | {(.identifier): .}) as $item ireduce ({}; . * $item )) as $uniqueMap | ( $uniqueMap | to_entries | .[]) as $item ireduce([]; . + $item.value)) as $mergedArray | select(fi == 0) | (.rules) = $mergedArray'

[mikefarah]

Take a look here for a similar example: https://mikefarah.gitbook.io/yq/operators/multiply-merge#merge-arrays-of-objects-together-matching-on-a-key