Terraform Replace Regex not working correctly

Question

I have a regex to replace any non word characters, underscores or spaces in one of my variables to sanitise the name to pass it to Route53.

It is replacing non alphanumeric and underscores but it is getting stuck on spaces.

I know the regex is \s for whitespaces but it seems to be ignoring it when the Terraform plan runs but if I run it through a regex checker it works fine.

identifier        = "qa-${lower(replace(var.dns_name,"/\\W|_|\\s/","-"))}"

FYI, `\s` is not even required in this case because `\W` already includes it. — 41686d6564 stands w. Palestine, Aug 30 '18 at 12:28
Even if I remove the `\s` it still breaks Terraform when theres a space in the name — Luke, Aug 30 '18 at 14:37
Yes, I expected that, that was just a side note. Your regex seems straight-forward to me, so this is most likely a problem with Terraform. Maybe someone with experience in Terraform can help you. — 41686d6564 stands w. Palestine, Aug 30 '18 at 14:42
@Luke - what does `plan` show you? 'computed'? What happens if you run `apply`? — KJH, Sep 03 '18 at 18:47

score 3 · Answer 1 · answered Mar 18 '20 at 06:20

3

I used your regex in Terraform v0.12.21 and tested it with spaces and various special characters:

dns_name = "abc DEF 123 ~'`!@#$%^&*()_+-=[]\\{}|;':\\./<>?\"\\'.com" 
identifier = "${lower(replace(var.dns_name,"/\\W|_|\\s/","-"))}"

and terraform plan showed that the regex correctly replaced anything other than letters, numbers, or hyphens with hyphens, which seems to be a what you needed for Route 53:

"abc-def-123-------------------------------------com"

But also be aware that domain names might not be able to contain two consecutive hyphens (see here).

answered Mar 18 '20 at 06:20

Employee

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"/\\W|_|\\s/" this saved my day. even though I didn't understand meaning of "|_|". – SNR Sep 16 '20 at 01:21
It seems `\W` does not match underscores: https://regex101.com/r/AWD8BA/2 – Employee Sep 16 '20 at 17:03
@SNR, it means "or" ("non-word char or vertical line or space") – Lucas Ross Jan 02 '22 at 06:35

Terraform Replace Regex not working correctly

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