Files
dnswatcher/internal/config/classify.go
T
sneak 2b034ae65a
check / check (push) Failing after 28s
config: watch a target listed twice only once (closes #207)
ClassifyTargets kept a name every time it appeared in DNSWATCHER_TARGETS,
so example.com,Example.com. put example.com in the domain list twice and
every check looked it up, checked its ports and its certificates twice,
sending two expiry warnings per TLS check. It now skips a name it has
already kept, comparing after the lower-casing and trailing-dot removal
it already did; the list keeps the order of first appearance.

Model: opus-5-5
2026-10-02 00:20:42 +00:00

91 lines
2.2 KiB
Go

package config
import (
"errors"
"fmt"
"strings"
"golang.org/x/net/publicsuffix"
)
// DNSNameType indicates whether a DNS name is an apex domain or a hostname.
type DNSNameType int
const (
// DNSNameTypeDomain indicates the name is an apex (eTLD+1) domain.
DNSNameTypeDomain DNSNameType = iota
// DNSNameTypeHostname indicates the name is a subdomain/hostname.
DNSNameTypeHostname
)
// ErrEmptyDNSName is returned when an empty string is passed to ClassifyDNSName.
var ErrEmptyDNSName = errors.New("empty DNS name")
// String returns the string representation of a DNSNameType.
func (t DNSNameType) String() string {
switch t {
case DNSNameTypeDomain:
return "domain"
case DNSNameTypeHostname:
return "hostname"
default:
return "unknown"
}
}
// ClassifyDNSName determines whether a DNS name is an apex domain or a
// hostname (subdomain) using the Public Suffix List. It returns an error
// if the input is empty or is itself a public suffix (e.g. "co.uk").
func ClassifyDNSName(name string) (DNSNameType, error) {
name = strings.ToLower(strings.TrimSuffix(strings.TrimSpace(name), "."))
if name == "" {
return 0, ErrEmptyDNSName
}
etld1, err := publicsuffix.EffectiveTLDPlusOne(name)
if err != nil {
return 0, fmt.Errorf("invalid DNS name %q: %w", name, err)
}
if name == etld1 {
return DNSNameTypeDomain, nil
}
return DNSNameTypeHostname, nil
}
// ClassifyTargets splits a list of DNS names into apex domains and
// hostnames using the Public Suffix List. It returns an error if any
// name cannot be classified. A name given more than once, in any letter
// case or with a trailing dot, is kept once.
func ClassifyTargets(targets []string) ([]string, []string, error) {
var domains, hostnames []string
seen := make(map[string]bool)
for _, t := range targets {
normalized := strings.ToLower(strings.TrimSuffix(strings.TrimSpace(t), "."))
if normalized == "" || seen[normalized] {
continue
}
seen[normalized] = true
typ, classErr := ClassifyDNSName(normalized)
if classErr != nil {
return nil, nil, classErr
}
switch typ {
case DNSNameTypeDomain:
domains = append(domains, normalized)
case DNSNameTypeHostname:
hostnames = append(hostnames, normalized)
}
}
return domains, hostnames, nil
}