Fix Secret creation with username with rfc-1123 non-allowed-chars.

[rodrigovalin]

• Fixes Credentials secret creation fails when user name contains underscore #879

Username with underscore in name will prevent Secret from being created.

Open questions:

• Should we add other characters to be replaced as well?

[irajdeep]

We should try to make any non-compatible RFC 1123 compatible, in addition to this(underscore) special case. We have had a discussion around this, in this ticket: https://jira.mongodb.org/browse/CLOUDP-95810

[rodrigovalin]

I think we should be good with transforming : / ? # [ ] @ into - as described in https://docs.mongodb.com/manual/reference/connection-string/. Do you agree that that solution is sufficient?

[irajdeep]

I think we should be good with transforming : / ? # [ ] @ into - as described in https://docs.mongodb.com/manual/reference/connection-string/. Do you agree that that solution is sufficient?

I think this would make sense. In addition to this, we should deal it the way we handle scramCredentialsSecretName which has the same problem:

1. Ask the user to provide an optional secret ref name for storing the credential.
2. Perform a DNS1123 name validation at the custom resource level if it is specified.

And if not specified then perform the transformation, if the generated name is non-complaint. WDYT.

[rodrigovalin]

Considering that we have an internal ticket for the bigger fix, we could fix this problem with this preliminary solution right away; and then work on the other implementation once that ticket has been triagged.

[irajdeep]

Yeah, for now, we can transform : / ? # [ ] @ into - and get this merged and revisit the optional secretRef later.

[rodrigovalin]

@irajdeep ready for another review

[irajdeep]

LGTM