provider/aws: Fix issue with Route53 and zero weighted records

[catsby]

Route 53 allows weighted records, with a weight of 0 meaning various things depending on the context.

Terraform's internal can sometimes confuse 0 for "not specified", which is incorrect in this case. As a result, a 0 weight was not possible... UNTIL NOW!

Here we default the weight to -1 as a sentinel value*. A record uses this default when the user does not specify weight in the record. A weight of -1 is ignored.

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*probably not a true sentinel value

[phinze]

*probably not a true sentinel value

Totally a sentinel value!

This LGTM - recommend updating the docs to with a similar note about the default and its meaning.

[phinze]

s/configuraiton/configuration/

[phinze]

One typo to fix and this looks good to go.

[scalp42]

@phinze or @catsby would that cause Terraform to delete and recreate the record ? Just brought chaos.

[phinze]

@scalp42 for aws_route53_record resources with weight unset, you'd see a diff going from "" => "-1" on this field, but the field is not ForceNew, so it should only trigger a ~ / update in the plan, and the update itself should be a noop.

Did you see different behavior here?

[scalp42]

I saw "0" => "-1" and we were down for couple seconds following the apply so I'm assuming it deleted/re-created the record.

We had the same issue with SGs where Terraform was deleting/re-creating rules with no changes (causing havoc again), so I'm assuming it's the same case.

[phinze]

Hm that's definitely not expected. Did the plan have a ~ or a -/+? If the plan shows ~ then the apply can't do a destroy/recreate out from under you. You'll also see Destroying... messages in the apply output if it does any recreating.

If you file a fresh issue with all the information you have, we can to dig in further to figure out what happened.

[scalp42]

@phinze Unfortunately I don't have the output anymore 🍶

Thanks for the feedback though.

[phinze]

Ah dang, too bad. Anytime you catch unexpected behavior definitely follow up with a fresh issue and we can help you run it down. 👍

[ghost]

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