google_cloud_run_v2_service should validate that scaling.min_instance_count is less than scaling.max_instance_count

[minimice]

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Description

With regards to this page

https://registry.terraform.io/providers/hashicorp/google/latest/docs/resources/cloud_run_v2_service

For the scaling block, update the documentation to state that max_instance_count is required to be present when min_instance_count is specified and vice versa. Failure to do so would result in the following error (here I did not specify max_instance_count only min_instance_count):

Error 400: Violation in UpdateServiceRequest.service.template.scaling.max_instance_count: must be greater or equal than min_instance_count.
│ Details:
│ [
│   {
│     "@type": "type.googleapis.com/google.rpc.BadRequest",
│     "fieldViolations": [
│       {
│         "description": "must be greater or equal than min_instance_count.",
│         "field": "Violation in UpdateServiceRequest.service.template.scaling.max_instance_count"
│       }
│     ]
│   }
│ ]

New or Affected Resource(s)

• google_cloud_run_v2_service

Potential Terraform Configuration

References

No response

b/357621141

[melinath]

From triage: Updated the title to reflect that not only should the docs be updated, we should also mark the fields as required_with each other. (Note: this is not currently documented but functions similarly to exactly_one_of - that is, all fields must be listed.) This shouldn't be a breaking change as long as the API always returns errors for invalid configurations.

[c2thorn]

https://github.com/GoogleCloudPlatform/magic-modules/blob/main/mmv1/templates/terraform/examples/cloudrunv2_service_sql.tf.erb#L8 is a passing example of max_instance_count without min_instance_count. So maybe this is only true for min_instance_count ?

[charan-kumar-137]

max_instance_count and min_instance_count are actually NOT required with each other.
The default for max_instance_count is 100 as mentioned in https://cloud.google.com/run/docs/configuring/max-instances#limits.

The above error might be due to setting min_instance_count greater than 100 (default).

[melinath]

Indeed - the error just says that max_instance_count needs to be greater than min_instance_count. Thanks for the catch!

[charan-kumar-137]

@melinath, Not just Cloud Run, Other Services where there is Range Arguments (min & max) would need this kind of validation.

Spanner - https://cloud.google.com/spanner/docs/reference/rest/v1/projects.instances#autoscalinglimits
Cloud Functions - https://cloud.google.com/functions/docs/reference/rest/v2/projects.locations.functions#serviceconfig

Since ValidateFunc is supported Only for Primitive Types. is there any way we can add Validation for Nested Objects.

[melinath]

you can do cross-field validation using a CustomizeDiff function. For MMv1 resources, this can be set up using the custom_diff top-level resource property (which takes a list of function names) and the functions can be defined using custom_code.constants.

[bskaplan]

Cloud Run has a dynamic default max instances, based on the user's available quota in the region and specified instance size which makes doing accurate checks in the client rather difficult. Is there a downside to leaving this as it is and letting the server validate it?