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IMPORT_TRANSFORM_SUFFIX: Fix for CNAMEs (#3192)

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Tom Limoncelli 2024-11-04 22:00:08 +00:00 • committed by GitHub
parent 1fde1332c1
commit 583cba3855
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3 changed files with 28 additions and 24 deletions
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5
documentation/language-reference/domain-modifiers/IMPORT_TRANSFORM_STRIP.md
View file

@ -16,10 +16,13 @@ Don't use this feature. It was added for a very specific situation at Stack Over
`IMPORT_TRANSFORM_STRIP` is the same as `IMPORT_TRANSFORM` with an additional parameter: `suffixstrip`.
When `IMPORT_TRANSFORM_STRIP` is generating the label for new records, it
checks the label. If the label ends with `suffixstrip`, that suffix is removed.
checks the label. If the label ends with `.` + `suffixstrip`, that suffix is removed.
If the label does not end with `suffixstrip`, an error is returned.
For CNAMEs, the `suffixstrip` is stripped from the beginning (prefix) of the target domain.
For example, if the domain is `com.extra` and the label is `foo.com`,
`IMPORT_TRANSFORM` would generate a label `foo.com.com.extra`.
`IMPORT_TRANSFORM_STRIP(... , '.com')` would generate
the label `foo.com.extra` instead.
A CNAME's target would be `foo.com.extra`.

15
pkg/normalize/validate.go
View file

@ -9,7 +9,6 @@ import (
"github.com/StackExchange/dnscontrol/v4/models"
"github.com/StackExchange/dnscontrol/v4/pkg/transform"
"github.com/StackExchange/dnscontrol/v4/providers"
"github.com/miekg/dns"
"github.com/miekg/dns/dnsutil"
)
@ -239,13 +238,14 @@ func checkTargets(rec *models.RecordConfig, domain string) (errs []error) {
}
func transformCNAME(target, oldDomain, newDomain, suffixstrip string) string {
// Canonicalize. If it isn't a FQDN, add the newDomain.
result := dnsutil.AddOrigin(target, oldDomain)
if dns.IsFqdn(result) {
result = result[:len(result)-1]
// Canonicalize the target. Add the newDomain minus the suffixstrip.
// foo -> foo.oldDomain.newDomain
// foo. -> foo.newDomain
nd := strings.TrimPrefix(newDomain, suffixstrip+".")
if strings.HasSuffix(target, ".") {
return target + nd + "."
}
result = strings.TrimSuffix(result, suffixstrip)
return dnsutil.AddOrigin(result, newDomain) + "."
return dnsutil.AddOrigin(target, oldDomain) + "." + nd + "."
}
func newRec(rec *models.RecordConfig, ttl uint32) *models.RecordConfig {
@ -260,6 +260,7 @@ func transformLabel(label, suffixstrip string) (string, error) {
if suffixstrip == "" {
return label, nil
}
suffixstrip = "." + suffixstrip
if !strings.HasSuffix(label, suffixstrip) {
return "", fmt.Errorf("label %q does not end with %q", label, suffixstrip)
}

32
pkg/normalize/validate_test.go
View file

@ -186,37 +186,37 @@ func Test_transform_cname_strip(t *testing.T) {
p []string
expected string
}{
{[]string{"ai.meta.stackexchange.com.", "stackexchange.com", "com.internal", ".com"},
{[]string{"ai.meta.stackexchange.com.", "stackexchange.com", "com.internal", "com"},
"ai.meta.stackexchange.com.internal."},
{[]string{"askubuntu.com.", "askubuntu.com", "com.internal", ".com"},
{[]string{"askubuntu.com.", "askubuntu.com", "com.internal", "com"},
"askubuntu.com.internal."},
{[]string{"blogoverflow.com.", "stackoverflow.com", "com.internal", ".com"},
{[]string{"blogoverflow.com.", "stackoverflow.com", "com.internal", "com"},
"blogoverflow.com.internal."},
{[]string{"careers.stackoverflow.com.", "stackoverflow.com", "com.internal", ".com"},
{[]string{"careers.stackoverflow.com.", "stackoverflow.com", "com.internal", "com"},
"careers.stackoverflow.com.internal."},
{[]string{"chat.stackexchange.com.", "askubuntu.com", "com.internal", ".com"},
{[]string{"chat.stackexchange.com.", "askubuntu.com", "com.internal", "com"},
"chat.stackexchange.com.internal."},
{[]string{"chat.stackexchange.com.", "stackoverflow.com", "com.internal", ".com"},
{[]string{"chat.stackexchange.com.", "stackoverflow.com", "com.internal", "com"},
"chat.stackexchange.com.internal."},
{[]string{"chat.stackexchange.com.", "superuser.com", "com.internal", ".com"},
{[]string{"chat.stackexchange.com.", "superuser.com", "com.internal", "com"},
"chat.stackexchange.com.internal."},
{[]string{"sstatic.net.", "sstatic.net", "net.internal", ".net"},
{[]string{"sstatic.net.", "sstatic.net", "net.internal", "net"},
"sstatic.net.internal."},
{[]string{"stackapps.com.", "stackapps.com", "com.internal", ".com"},
{[]string{"stackapps.com.", "stackapps.com", "com.internal", "com"},
"stackapps.com.internal."},
{[]string{"stackexchange.com.", "stackexchange.com", "com.internal", ".com"},
{[]string{"stackexchange.com.", "stackexchange.com", "com.internal", "com"},
"stackexchange.com.internal."},
{[]string{"stackoverflow.com.", "stackoverflow.com", "com.internal", ".com"},
{[]string{"stackoverflow.com.", "stackoverflow.com", "com.internal", "com"},
"stackoverflow.com.internal."},
{[]string{"superuser.com.", "superuser.com", "com.internal", ".com"},
{[]string{"superuser.com.", "superuser.com", "com.internal", "com"},
"superuser.com.internal."},
{[]string{"teststackoverflow.com.", "teststackoverflow.com", "com.internal", ".com"},
{[]string{"teststackoverflow.com.", "teststackoverflow.com", "com.internal", "com"},
"teststackoverflow.com.internal."},
{[]string{"webapps.stackexchange.com.", "stackexchange.com", "com.internal", ".com"},
{[]string{"webapps.stackexchange.com.", "stackexchange.com", "com.internal", "com"},
"webapps.stackexchange.com.internal."},
//
{[]string{"sstatic.net.", "sstatic.net", "com.internal", ".com"},
"sstatic.net.com.internal."},
{[]string{"sstatic.net.", "sstatic.net", "com.internal", "com"},
"sstatic.net.internal."},
}
for _, test := range tests {