Add support for provisioners to modules

[radeksimko]

It is possible to use provisioners inside the module's code, but in case of local-exec, I'd personally discourage people from doing so (depending on what they're trying to do obviously).

I think it's hard to guess for the module's author what platform that local system will be etc. etc.

I can imagine the implementation could be as simple as this:

module "my_rds_instance" {
  source = "github.com/terraform-community-modules/tf_aws_rds"

  rds_instance_name = "${var.rds_instance_name}"
  rds_allocated_storage = "${var.rds_allocated_storage}"
  rds_engine_type = "${var.rds_engine_type}"
  rds_engine_version = "${var.rds_engine_version}"
  database_name = "${var.database_name}"
  database_user = "${var.database_user}"
  database_password = "${var.database_password}"
  rds_security_group_id = "${var.rds_security_group_id}"
  db_parameter_group = "${var.db_parameter_group}"

  provisioner "local-exec" {
    command = "echo 'export DB_HOST=http://${self.instance_endpoint}' > ./env/db-host.sh"
  }
}

[joescii]

+1

[eppdot]

+1

[wr0ngway]

+1

[catsby]

Interesting idea, I wonder, do you think null_resource is a viable alternative here?

• https://www.terraform.io/docs/provisioners/null_resource.html

Or the template_file?

• https://www.terraform.io/docs/providers/template/d/file.html

[mitchellh]

I agree with @catsby that the null resource + depends_on referencing modules (new in 0.8) is the way to go here.

The biggest complication here is: how do we know when a module is new? Do we just do it the first time a module completely applies? What if resources are added/removed to a module? Do we do it whenever dependent resources in the module recreate? etc.

I'm not saying those are unsolvable problems by any means, but I think we have a ways to go in core land before we can look into this (such as splitting provisioners out into their own graph nodes). In the mean time, there is a great workaround with null_resource depending on a module or triggered by module outputs.

[aleclarson]

Is there documentation for null_resource triggering when a module is created? (not sure if that's the correct terminology here)

I'm trying to remote_exec on an Openstack resource that's created in a module.

module "server" {
  source="./openstack"
}

resource "null_resource" "something" {
  triggers {
    # What goes here?
  }
  provisioner "remote_exec" {
    inline = [
      "echo Hello world"
    ]
  }
}

edit: Looks like depends_on is what I'm looking for. Sorry! #1178

[ghost]

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