terraform temporary/intermediate variables in loops?

Question

I would like to know if it is possible to use temporary variables inside a for loop for intermediate computation. If yes, what is the syntax to use that, the example is simplified just to illustrate the problem. This example code works. I've commented the portion which doesn't work, but would like to know how to use intermediate variable. Thanks!


locals {
  nestedmap = <<-EOT
  user-john:
    db:  "db34"
    tables:
      t1:
        rows: 4
      t2:
        rows: 8
  user-chris:
    db:  "db22"
    tables:
      t1:
        rows: 3
      t2:
        rows: 7
  user-mary:
    db:  "db78"
    tables:
      t1:
        rows: 2
      t2:
        rows: 10
  EOT

  flatlist = flatten([
    for ux_key, ux_val in yamldecode(local.nestedmap): [
      for tx_key, tx_val in ux_val.tables: {
        pfx = trimprefix(ux_key, "user-")
        #key = "${pfx}-${tx_key}"
        key = "${trimprefix(ux_key, "user-")}-${tx_key}"
        db = ux_val.db
        rows = tx_val.rows
      }
    ]
  ])
  flatmap = {for fx in local.flatlist:  fx.key => fx}
}

"which doesn't work" - what does it mean? What errors do you get? — Marcin, Feb 24 '22 at 06:11
$terraform validate ╷ │ Error: Invalid reference │ │ on loopvar.tf line 46, in locals: │ 46: key = "${pfx}-${tx_key}" │ │ A reference to a resource type must be followed by at least one attribute access, specifying the resource name. ╵ — xbalaji, Feb 24 '22 at 06:29
that is what my question is, how to use intermediate variables — xbalaji, Feb 24 '22 at 06:45
oops sorry, I was trying to find where I can click accept, I clicked the up vote button, sorry about that. I appreciate your time and your input. — xbalaji, Feb 27 '22 at 23:30

score 1 · Accepted Answer · answered Feb 24 '22 at 07:11

1

There are no intermediate variables in TF. You have to just repeat trimprefix(ux_key, "user-"):

  flatlist = flatten([
    for ux_key, ux_val in yamldecode(local.nestedmap): [
      for tx_key, tx_val in ux_val.tables: {
        pfx = trimprefix(ux_key, "user-")
        key = "${trimprefix(ux_key, "user-")}-${tx_key}"
        db = ux_val.db
        rows = tx_val.rows
      }
    ]
  ])

answered Feb 24 '22 at 07:11

Marcin

215,873
14
235
294

1

If you can call this a language, you can certainly call it terrabad. – ctpenrose May 10 '23 at 20:45

score 0 · Answer 2 · answered Feb 27 '22 at 23:32

0

For anyone interested in more discussions on this, have a look at - https://www.reddit.com/r/Terraform/comments/t03nfr/terraform_temporaryintermediate_variables_in_loops/

sharing here, so it is useful for others who are faced with similar question

answered Feb 27 '22 at 23:32

xbalaji

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7
16

terraform temporary/intermediate variables in loops?

2 Answers2