interpolate: Interpolate computed list attributes

[radeksimko]

This will solve issues with all list attributes that are computed and currently can't be actually used as lists (i.e. we can't use built-in functions like join()).

The current output coming from valueResourceVar is config.UnknownVariableValue since it's looking for resource.attribute whereas it's present as resource.attribute.# + resource.attribute.0 + resource.attribute.1 etc. in the given map.

Status:

• Implementation for resources w/out count
• Implementation for resources w/ count
• Tests for resources w/out count
• Tests for resources w/ count

Related: #1999

Test plan

TypeList

resource "aws_route53_zone" "main" {
  name = "mainexample.com"
}

output "new" {
  value = "${join(" ", aws_route53_zone.main.name_servers)}"
}
output "old" {
  value = "${aws_route53_zone.main.name_servers.0} ${aws_route53_zone.main.name_servers.1} ${aws_route53_zone.main.name_servers.2} ${aws_route53_zone.main.name_servers.3}"
}

TypeMap

resource "aws_instance" "sample" {
  ami = "ami-2cd3dc44"
  instance_type = "t2.micro"

  tags {
    Name = "TerraformTest"
    CustomTag = "Yada Yada"
  }
}

output "tags" {
  value = "${aws_instance.sample.tags.Name}"
}

resource "aws_instance" "sample" {
  ami = "ami-2cd3dc44"
  instance_type = "t2.micro"

  # not sure if anyone would want to do this, but it's possible
  tags {
    "0" = "TerraformTest"
    "1" = "Yada Yada"
  }
}

output "tags" {
  value = "${join(",", aws_instance.sample.tags)}"
}

TypeSet

resource "aws_elb" "bar" {
  name = "foobar-terraform-elb"
  availability_zones = ["us-east-1b", "us-east-1c", "us-east-1d"]

  listener {
    instance_port = 8080
    instance_protocol = "http"
    lb_port = 80
    lb_protocol = "http"
  }
}

output "azs" {
  value = "${join(",", aws_elb.bar.availability_zones)}"
}

Impact

$ grep -l -R -E '(TypeSet|TypeList)' ./builtin/providers/* | sort | uniq

./builtin/providers/atlas/resource_artifact.go
./builtin/providers/aws/autoscaling_tags.go
./builtin/providers/aws/provider.go
./builtin/providers/aws/resource_aws_autoscaling_group.go
./builtin/providers/aws/resource_aws_autoscaling_notification.go
./builtin/providers/aws/resource_aws_cloudwatch_metric_alarm.go
./builtin/providers/aws/resource_aws_db_instance.go
./builtin/providers/aws/resource_aws_db_parameter_group.go
./builtin/providers/aws/resource_aws_db_security_group.go
./builtin/providers/aws/resource_aws_db_subnet_group.go
./builtin/providers/aws/resource_aws_dynamodb_table.go
./builtin/providers/aws/resource_aws_ecs_service.go
./builtin/providers/aws/resource_aws_ecs_task_definition.go
./builtin/providers/aws/resource_aws_elasticache_cluster.go
./builtin/providers/aws/resource_aws_elasticache_parameter_group.go
./builtin/providers/aws/resource_aws_elasticache_security_group.go
./builtin/providers/aws/resource_aws_elasticache_subnet_group.go
./builtin/providers/aws/resource_aws_elb.go
./builtin/providers/aws/resource_aws_iam_group_membership.go
./builtin/providers/aws/resource_aws_iam_instance_profile.go
./builtin/providers/aws/resource_aws_iam_policy_attachment.go
./builtin/providers/aws/resource_aws_instance.go
./builtin/providers/aws/resource_aws_launch_configuration.go
./builtin/providers/aws/resource_aws_network_acl.go
./builtin/providers/aws/resource_aws_network_interface.go
./builtin/providers/aws/resource_aws_proxy_protocol_policy.go
./builtin/providers/aws/resource_aws_route53_delegation_set.go
./builtin/providers/aws/resource_aws_route53_record.go
./builtin/providers/aws/resource_aws_route53_zone.go
./builtin/providers/aws/resource_aws_route_table.go
./builtin/providers/aws/resource_aws_s3_bucket.go
./builtin/providers/aws/resource_aws_security_group.go
./builtin/providers/aws/resource_aws_security_group_rule.go
./builtin/providers/aws/resource_aws_vpc_dhcp_options.go
./builtin/providers/aws/resource_aws_vpn_connection.go
./builtin/providers/azure/resource_azure_instance.go
./builtin/providers/azure/resource_azure_local_network.go
./builtin/providers/azure/resource_azure_security_group_rule.go
./builtin/providers/azure/resource_azure_sql_database_server_firewall_rule.go
./builtin/providers/azure/resource_azure_virtual_network.go
./builtin/providers/cloudstack/resource_cloudstack_egress_firewall.go
./builtin/providers/cloudstack/resource_cloudstack_firewall.go
./builtin/providers/cloudstack/resource_cloudstack_network_acl_rule.go
./builtin/providers/cloudstack/resource_cloudstack_port_forward.go
./builtin/providers/consul/resource_consul_keys.go
./builtin/providers/digitalocean/resource_digitalocean_droplet.go
./builtin/providers/docker/resource_docker_container.go
./builtin/providers/google/resource_compute_firewall.go
./builtin/providers/google/resource_compute_instance.go
./builtin/providers/google/resource_compute_instance_template.go
./builtin/providers/google/resource_compute_route.go
./builtin/providers/google/resource_compute_target_pool.go
./builtin/providers/google/resource_dns_managed_zone.go
./builtin/providers/google/resource_dns_record_set.go
./builtin/providers/heroku/resource_heroku_addon.go
./builtin/providers/heroku/resource_heroku_app.go
./builtin/providers/mailgun/resource_mailgun_domain.go
./builtin/providers/openstack/resource_openstack_blockstorage_volume_v1.go
./builtin/providers/openstack/resource_openstack_compute_instance_v2.go
./builtin/providers/openstack/resource_openstack_compute_secgroup_v2.go
./builtin/providers/openstack/resource_openstack_compute_servergroup_v2.go
./builtin/providers/openstack/resource_openstack_fw_policy_v1.go
./builtin/providers/openstack/resource_openstack_lb_pool_v1.go
./builtin/providers/openstack/resource_openstack_networking_subnet_v2.go

[mitchellh]

On a preliminary scan this looks good to me. I'm going to keep scanning to look for anything... but if the rest of the unit tests pass its a pretty good sign.

@phinze can you take a look too? I'd feel better if you checked off on this as well.

[phinze]

@radeksimko this is looking great so far!

This implementation applies to all three of TypeList, TypeSet, and TypeMap, correct? I just want to make sure we clarify that in variable / function naming. I see you picked up on the convention of calling these "multi" variables - which is good. I think there are just a few places you still call them "lists" which confused me for a second.

[phinze]

Hmm yeah I guess I'd expect an empty list here, but a single InterpSplitDelim indicates ["", ""] right? Another valid return here would be a list of two empty lists [[], []], but we're "flattening" the two sub-lists already it seems like [] is what we should shoot for.

[radeksimko]

I was personally tempted to make it a single empty list as well, but considering the debate in here #1495 (comment) I realise some people may consider that to be way too magic.

[phinze]

I don't think it's worth rabbit holing too much on this, so I'm ultimately fine with it either way, but my vote would still be for a single list, since our "string-hack" lists don't allow for nesting right now.

[radeksimko]

I see your point, I just need to find out how to express an empty list via our "string-hack".

[phinze]

I just need to find out how to express an empty list via our "string-hack".

I've got an idea on that - related to fix for #2240 - finishing up a PR now and I'll highlight you.

[radeksimko]

@phinze Is there any update on the fix for #2240 ?

[radeksimko]

I reckon this is the related PR: #2504 which should make representation of empty list possible.

[phinze]

@radeksimko yep! finally 😀

If you rebase on top of that and use the StringList type - I believe this might "just work". (And I'm happy to help out if it does not.)

[zollie]

Hey @radeksimko,

Do you plan on updating to StringList? I am trying to render the route53.nameservers list as in your example ...

[radeksimko]

@zollie Thanks for pinging me, I was a bit busy with other things, but I do plan to update it fairly soon. The change may not make it to 0.6.0 though, which is knocking on the door (AFAIK).

I should have some time this week - can't be more specific now, sorry.

[zollie]

Cool...thanks! Looking forward to it.

[radeksimko]

All refactoring finished.

@phinze to your question:

This implementation applies to all three of TypeList, TypeSet, and TypeMap, correct?

It applies to TypeList & TypeSet and may eventually apply to TypeMap (if anyone decides to use numbered keys for whatever reason). See examples in Test Plan in my very first comment of this thread.

I have also added a couple of tests for the string_list.

[phinze]

Thanks to @radeksimko for reminding me about this one. LGTM - landing, which I believe should fix #2795!

[phinze]

p.s. great work on this, @radeksimko! 😀

[ghost]

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