Added check for beta feature field istio_enabled

[richardmcsong]

Some beta feature fields may not be returned by the Google API call that terraform uses.

According to Google Support (Case 20165122), when asked why certain Google API calls don't return istio_config or pod_security_policy_config:

Actually the fields are not optional. If you have those features enabled in your cluster it will show up in the description. These fields default to disabled and when they are disabled they are not present in the rest resource which is why these fields are missing in the cluster description. The API is configured to register them as disabled if left blank.

Since the terraform provider upstream operates by transpiling the API call into the correct resources, I thought it might be most appropriate to code defensively here and check for the field before trying to access it. Fixes #226

I also added resource_usage_export_config support in this PR (https://www.terraform.io/docs/providers/google/r/container_cluster.html#resource_usage_export_config).

[morgante]

Thanks for the contribution! It looks pretty good, just needs a type change and to fix merge conflicts.

[morgante]

FYI we have consolidated the zonal and regional resources into a single resource so this PR will need to be rebased. Thanks!

[richardmcsong]

I'm sorry if this is a really stupid question, but why is this happening? it doesn't error out if i swap over to google_container_cluster.primary.addons_config.0.istio_config == [], but i thought when the expression evals to false that it goes to the second result after the colon, not to the first... Am I going nuts?

[paulpalamarchuk]

I'm sorry if this is a really stupid question, but why is this happening? it doesn't error out if i swap over to google_container_cluster.primary.addons_config.0.istio_config == [], but i thought when the expression evals to false that it goes to the second result after the colon, not to the first... Am I going nuts?

@richardmcsong google_container_cluster.primary.addons_config.0.istio_config != [] not the same as google_container_cluster.primary.addons_config.0.istio_config != [{}] (empty list is not equal to list with one element that is empty object).

[paulpalamarchuk]

@richardmcsong Define, please, version of provider google-beta "~> 2.10.0", to use resource_usage_export_config and remove older version mentions. Thank you

[richardmcsong]

I'm sorry if this is a really stupid question, but why is this happening? it doesn't error out if i swap over to google_container_cluster.primary.addons_config.0.istio_config == [], but i thought when the expression evals to false that it goes to the second result after the colon, not to the first... Am I going nuts?

@richardmcsong google_container_cluster.primary.addons_config.0.istio_config != [] not the same as google_container_cluster.primary.addons_config.0.istio_config != [{}] (empty list is not equal to list with one element that is empty object).

But it says an EMPTY list of objects, not a list of empty objects. Also, I tried doing [{}]:

[morgante]

#238 was merged to provide resource usage export config, but the beta feature checks are still helpful. Can you rebase?

[richardmcsong]

Finally got a chance to rebase. Noticed the other beta features were already done, just missing the istio one. Also fixed some naming, because it's actually detecting for the disabled flag, not the enabled flag.