Cycle through two certs every 5 secs

main.tf

# Ultimately we obviously increase the numbers to e.g. 6 months

locals {
  plantimestamp = plantimestamp()
  secs          = format("%02d", floor(tonumber(formatdate("ss", local.plantimestamp)) / 10) * 10)
  rounded       = "${formatdate("YYYY-MM-DD", local.plantimestamp)}T${formatdate("hh:mm", local.plantimestamp)}:${local.secs}Z"
  diff          = timecmp(local.value2, local.plantimestamp)
  s1            = local.rounded
  value2        = timeadd(local.rounded, "5s")
  s2            = local.diff == 1 ? timeadd(local.rounded, "-5s") : local.value2
}

output "active_cert" {
  #value = local.list[floor(local.timestamp_number / 5) % length(local.list)]
  value = timecmp(local.s1, local.s2) == 1 ? "c1" : "c2"
}

resource "terraform_data" "s1" {
  input = local.s1
}

resource "terraform_data" "s2" {
  input = local.s2
}

resource "terraform_data" "c1" {
  lifecycle {
    replace_triggered_by = [terraform_data.s1]
  }
}

resource "terraform_data" "c2" {
  lifecycle {
    replace_triggered_by = [terraform_data.s2]
  }
}

# Output:
# active_cert = "c1"
# active_cert = "c2"
# alternating every 5 secs