Terraform meta-argument: depends on

• https://www.terraform.io/language/meta-arguments/depends_on

• Terraform: depends_on for modules (https://github.com/hashicorp/terraform/blob/v0.13/CHANGELOG.md), Terraform 0.13.0 (Aug 2020)

Official example

resource "aws_iam_role" "example" {
  name = "example"

  # assume_role_policy is omitted for brevity in this example. Refer to the
  # documentation for aws_iam_role for a complete example.
  assume_role_policy = "..."
}

resource "aws_iam_instance_profile" "example" {
  # Because this expression refers to the role, Terraform can infer
  # automatically that the role must be created first.
  role = aws_iam_role.example.name
}

resource "aws_iam_role_policy" "example" {
  name   = "example"
  role   = aws_iam_role.example.name
  policy = jsonencode({
    "Statement" = [{
      # This policy allows software running on the EC2 instance to
      # access the S3 API.
      "Action" = "s3:*",
      "Effect" = "Allow",
    }],
  })
}

resource "aws_instance" "example" {
  ami           = "ami-a1b2c3d4"
  instance_type = "t2.micro"

  # Terraform can infer from this that the instance profile must
  # be created before the EC2 instance.
  iam_instance_profile = aws_iam_instance_profile.example

  # However, if software running in this EC2 instance needs access
  # to the S3 API in order to boot properly, there is also a "hidden"
  # dependency on the aws_iam_role_policy that Terraform cannot
  # automatically infer, so it must be declared explicitly:
  depends_on = [
    aws_iam_role_policy.example
  ]
}

Errors

• Cannot depend on container ...

Related

• Terraform conditional expressions and count
• Terraform: output
• Terraform: aws_ecs_task_definition
• Docker compose file: docker-compose.yml

See also

• Terraform functions, Terraform collection functions: tolist, toset, length, sum, file, join, depends_on, zipmap, replace, lookup, read files, concat, merge, templatefile, for_each, format, element, slice, try, filebase64, upper, filemd5, coalesce, formatlist, flatten