helm - replace special chars with underscore

Question

New to k8s & helm.

Trying to declare a field in a deployment using the {{ .Release.Name }}, that must not contain characters other than letters (upper + lower), digits and _.

Excluded characters should be replaced with _, for instance: feature/my-feature-1130

should replaced with: feature_my_feature_1130

Can one please help me creating such of a field?

Many Thanks in advance!

Rivet

Try {{ regexReplaceAll "\\W+" .Release.Name "_" }} – Delia

@WiktorStribiżew Seems to do the trick. Thanks! – Rivet

Answer 1

You may use regexReplaceAll like this:

{{ regexReplaceAll "\\W+" .Release.Name "_" }}

See the regex demo.

\W+ matches 1 or more occurrences of any non-word char (a char other than letter, digit and _) and replaces them with _.

The \ escaping symbol needs another escaping to form the regex escape since it is used to form string escape sequences.

Note the order of the arguments to the function, the pattern comes first, then the input string and then the replacement pattern.

Harriot

Could you resolve it with regexReplaceAll ? I am trying to do something similar, but to only replace the first occurrence, but i am not able to do it. For instance: feature-my-feature-1130 should replaced with: feature/my_feature_1130 If someone, can share some tips. – Deadwood

@Littlecrazy If you mean you need to replace the first - with /, you can use {{ regexReplaceAll "^([^-]*)-" .Release.Name "${1}/" }}. – Delia

thank you for sharing. It is works, what does it mean ${1} – Deadwood

@Littlecrazy ${1} is a replacement backreference. It refers to the text captured with the first capturing group. – Delia