Terraform

DEBUG

export TF_LOG=TRACE
export TF_LOG=DEBUG
export TF_LOG=INFO
export TF_LOG=WARN
export TF_LOG=ERROR

IF Statement

I want an module in terraform which is able to execute two different codes.
One with a image from a Publisher and other with a custom image.
Codes above show how to specify both operations in the same module:

module "virtualmachine" {
  source = "git@github.com:accountname/git.git///path?ref=xxxxxxxx"
  vm_name = "virtualmachine"
  location = "East US 2"
  vm_image_reference = "no"
  image_publisher = "MicrosoftSQLServer"
  image_offer     = "SQL2016SP1-WS2016"
  image_sku       = "Enterprise"
  image_version   = "latest"
  vm_size = "Standard_DS11_v2"
  vm_disk_type = "Premium_LRS"
  vm_data_disks = ["1023"]
}

module "virtualmachine" {
  source = "git@github.com:accountname/git.git///path?ref=xxxxxxxx"
  vm_name = "virtualmachine"
  location = "East US 2"
  vm_image_reference = "yes"
  vm_image = "/subscriptions/xxxxxxxxxxxxx/resourceGroups/Images/providers/Microsoft.Compute/images/centos_720201230"
  vm_size = "Standard_DS11_v2"
  vm_disk_type = "Premium_LRS"
  vm_data_disks = ["1023"]
}

resource "azurerm_virtual_machine" "image" {
  count = "${format("%.1s", var.vm_image_reference) == "y" ? 1 : 0}"
.
.
.
}
resource "azurerm_virtual_machine" "market" {
  count = "${format("%.1s", var.vm_image_reference) == "n" ? 1 : 0}"
.
.
.
}

Example with Null Resource

resource "null_resource" "zero" {
  count = "${signum(format("%.1s", var.yes) == "y" ? 1 : 0) * signum(format("%.1s", var.no) == "y" ? 1 : 0)}"
  provisioner "local-exec" {
    command = "echo zero}"
  }
}
resource "null_resource" "one" {
  count = "${signum(format("%.1s", var.yes) == "y" ? 1 : 0) * signum(format("%.1s", var.yes) == "y" ? 1 : 0)}"
  provisioner "local-exec" {
    command = "echo one}"
  }
}
variable "yes" {
  default = "yes"
}
variable "no" {
  default = "no"
}

Execution:

$ terraform plan
Refreshing Terraform state in-memory prior to plan...
The refreshed state will be used to calculate this plan, but will not be
persisted to local or remote state storage.


------------------------------------------------------------------------

An execution plan has been generated and is shown below.
Resource actions are indicated with the following symbols:
  + create

Terraform will perform the following actions:

  # null_resource.um[0] will be created
  + resource "null_resource" "one" {
      + id = (known after apply)
    }

Plan: 1 to add, 0 to change, 0 to destroy.

------------------------------------------------------------------------

Note: You didn't specify an "-out" parameter to save this plan, so Terraform
can't guarantee that exactly these actions will be performed if
"terraform apply" is subsequently run.

AND

foo	bar	result
0	0	0
0	1	0
1	1	1

count = "${var.foo * var.bar}"

OR

foo	bar	result
0	0	0
0	1	1
1	1	1

count = "${signum(var.foo + var.bar)}"

Links

• Interpolation Syntax
• Source here
• DEBUG
• Null Resource
• Terraform tips & tricks: loops, if-statements, and gotchas
• Terraform Resource languages