Terraform: Conditionally use if a key is present under a map otherwise use default value

[udayanms]

Current Terraform Version

...

Use-cases

Attempted Solutions

Proposal

Usually other languages has feature ifdefined(var.key) to check if the variable is defined.

References

Something like is present in many languages e.g.
if (typeof variable !== 'undefined')

[mildwonkey]

The lookup() function supports this:

lookup(map, key, default)

[jurgenweber]

how about nested maps?

``` access_points = {
marketing = {
posix_user = {
gid = "1000"
uid = "1000"
secondary_gids = "0755"
},
creation_info = {
gid = "1000"
uid = "1000"
permissions = "0755"
}
}
data = {
posix_user = {
gid = "1000"
uid = "1000"
permissions = "0755"
}
}
}

creation_info {
  owner_gid     = lookup(var.access_points[each.key], "creation_info", null) == null ? null : lookup(var.access_points[each.key]["creation_info"], "gid", null)
  owner_uid     = lookup(var.access_points[each.key], "creation_info", null) == null ? null : lookup(var.access_points[each.key]["creation_info"], "uid", null)
  permissions   = lookup(var.access_points[each.key], "creation_info", null) == null ? null : lookup(var.access_points[each.key]["creation_info"], "permissions", null)
}

```

I am trying to test for 'creation_info' before I attempt to use keys in 'creation_info'. I keep getting errors nesting lookup.

[dec5e]

The only option I've found to get a binary result with lookup looks ugly:

key_exists = lookup(map, key, default) != default

Is there a better way?

[jurgenweber]

not that I know of.

[jan-philippkappmeier-tomtom]

It can be done like this:

key_exists = contains(keys(map), key)