Check if array exists

[gituser022]

Hello,

Iam struggling to write OPA policy rule that should check an element of an array but the array itself is optional.

Input:

{ "load_balancer":[{ "target_group_arn":true }] }

Policy Rule:

deny[message] { message := "Target ARN is missing" lb:= [rule | rule:= input.load_balancer[_] ; rule.target_group_arn ] ???? }

I am not sure how could I proceed. If I simply say count(lb) > 0 , when array is not defined, it is an empty array. Empty array could also be possible when every load_balancer has target_group_arn.

I only need to deny if array is missing or if any of the element in array doesn't have target_group_arn

How should I proceed on this ?

Thanks

[charlieegan3]

Hey, 🙂

How about something like this: https://play.openpolicyagent.org/p/Ecmh6Q2FeJ

It's common when writing rules to handle different cases with different deny blocks as I have done here. Hope that makes sense.

[gituser022]

That worked like Charm. Thanks for quick response.

[charlieegan3]

No problem!