[GitHub] [trafficcontrol] zrhoffman commented on a change in pull request #4107: Adding ability to use zone root records

[GitBox <gi...@apache.org>]

zrhoffman commented on a change in pull request #4107:
URL: https://github.com/apache/trafficcontrol/pull/4107#discussion_r432062045



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File path: traffic_ops/traffic_ops_golang/staticdnsentry/staticdnsentry.go
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@@ -106,7 +107,7 @@ func (staticDNSEntry TOStaticDNSEntry) Validate() error {
 	}
 
 	errs := validation.Errors{
-		"host":              validation.Validate(staticDNSEntry.Host, validation.Required, is.DNSName),
+		"host":              validation.Validate(staticDNSEntry.Host, validation.Required, validation.Match(regexp.MustCompile(`^([a-zA-Z0-9_@*]{1}[a-zA-Z0-9_-]{0,62}){1}(\.[a-zA-Z0-9_]{1}[a-zA-Z0-9_-]{0,62})*[\._]?$`))),

Review comment:
       This regex looks identical to [the one used in asaskevich/govalidator](https://github.com/asaskevich/govalidator/blob/7e6e9a9af9/patterns.go#L32) but with `@` and `*` added to the first character class.
   
   It matches all of our use cases but it also matches undesired ones as well:
   * `s*bdomain.domain.com`, which violates [RFC 1034](https://tools.ietf.org/html/rfc1034#section-4.3.3)
   * `@.domain.com`, which violates [RFC 1035](https://tools.ietf.org/html/rfc1035#page-35)
   
   `@` should only be allowed if it is the entire entry, an `*` should only be allowed in the form `*.<anydomain>` (including free-standing `*`).
   
   This pattern should match all of our use cases. Feel free to use it:
   ```regex
   ^(@|((\*|([a-zA-Z0-9_][a-zA-Z0-9_-]{0,62}))(\.[a-zA-Z0-9_][a-zA-Z0-9_-]{0,62})*[._]?))$
   ```




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