Added: random_id for mysql instance name

[konstantin-recurly]

There is an issue if you would like to create a DB with the same name. With the current approach, you need to change the name every time or you have to work around and use something like random_id

If I delete my instance, can I reuse the instance name?
Yes, but not right away. The instance name is unavailable for up to a week before it can be reused.

More information is here Managing Your Instances

[morgante]

I'm not sure we want to include this in the module. While it's indeed necessary for recreating instances after deletion, it's also following a very specific pattern which doesn't necessarily match what everyone wants.

[konstantin-recurly]

Maybe, it would be nice to have that as an option. Like

resource "random_id" "prefix" {
  byte_length = 4
}

resource "google_sql_database_instance" "default" {
  provider            = google-beta
  project             = var.project_id
  name                = var.instance_name_prefix  ? "${var.name}-${random_id.prefix.hex}"  : var.name

How does it sound to you?

[morgante]

Yeah I think we could make it optional with a random_instance_name boolean variable.

[konstantin-recurly]

@morgante Updated the PR

[morgante]

Thanks, just some nits. It'd also be nice to have this added to all the submodules.

[morgante]

Tests are failing as you need to index for the random ID:

Error: Missing resource instance key

  on ../../../modules/mssql/main.tf line 43, in resource "google_sql_database_instance" "default":
  43:   name             = var.random_instance_name ? "${var.name}-${random_id.suffix.hex}" : var.name

Because random_id.suffix has "count" set, its attributes must be accessed on
specific instances.

[morgante]

Thanks for the contribution.

[konstantin-recurly]

One more thing that I have noticed. Seems that now we don't need this part in examples
https://github.com/terraform-google-modules/terraform-google-sql-db/blob/master/examples/mysql-public/main.tf#L37-L44

resource "random_id" "suffix" {
  byte_length = 5
}

locals {
  /*
    Random instance name needed because:
    "You cannot reuse an instance name for up to a week after you have deleted an instance."
    See https://cloud.google.com/sql/docs/mysql/delete-instance for details.
  */
  instance_name = "${var.db_name}-${random_id.suffix.hex}"
}

Now we should be able to use this

module "safer-mysql-db" {
  source           = "../../modules/mysql"
  name             = var.db_name
  random_instance_name = true
  database_version = "MYSQL_5_6"
  project_id = var.project_id

[morgante]

Indeed! Looks like that example could be cleaned up.

We can also remove random_Id from safer-mysql and just pass through the random_instance_name variable: https://github.com/terraform-google-modules/terraform-google-sql-db/blob/master/modules/safer_mysql/main.tf#L16

Do you mind doing a follow-up PR to fix those issues?