Fix PowerDNS regex domain filter

docs/tutorials/pdns.md

@@ -63,6 +63,9 @@ eg. ```--domain-filter=.example.org``` will allow *only* zones that end in `.exa
 
 The filter can also match parent zones. For example `--domain-filter=a.example.com` will allow for zone `example.com`. If you want to match parent zones, you cannot pre-pend your filter with a ".", eg. `--domain-filter=.example.com` will not attempt to match parent zones.
 
+### Regex Domain Filter (`--regex-domain-filter`)
+`--regex-domain-filter` limits possible domains and target zone with a regex. It overrides domain filters and can be specified only once.
+
 ## RBAC
 
 If your cluster is RBAC enabled, you also need to setup the following, before you can run external-dns:
@@ -169,4 +172,3 @@ Once the API shows the record correctly, you can double check your record using:
 ```bash
 $ dig @${PDNS_FQDN} echo.example.com.
 ```
-

endpoint/domain_filter.go

@@ -90,10 +90,15 @@ func NewRegexDomainFilter(regexDomainFilter *regexp.Regexp, regexDomainExclusion
 	return DomainFilter{regex: regexDomainFilter, regexExclusion: regexDomainExclusion}
 }
 
+// IsRegexFilterConfigured checks if regex filter is set
+func (df *DomainFilter) IsRegexFilterConfigured() bool {
+	return df.regex != nil && df.regex.String() != ""
+}
+
 // Match checks whether a domain can be found in the DomainFilter.
 // RegexFilter takes precedence over Filters
 func (df DomainFilter) Match(domain string) bool {
-	if df.regex != nil && df.regex.String() != "" || df.regexExclusion != nil && df.regexExclusion.String() != "" {
+	if df.IsRegexFilterConfigured() || df.regexExclusion != nil && df.regexExclusion.String() != "" {
 		return matchRegex(df.regex, df.regexExclusion, domain)
 	}
 
@@ -164,7 +169,7 @@ func (df DomainFilter) MatchParent(domain string) bool {
 
 // IsConfigured returns true if any inclusion or exclusion rules have been specified.
 func (df DomainFilter) IsConfigured() bool {
-	if df.regex != nil && df.regex.String() != "" {
+	if df.IsRegexFilterConfigured() {
 		return true
 	} else if df.regexExclusion != nil && df.regexExclusion.String() != "" {
 		return true

provider/pdns/pdns.go

@@ -166,7 +166,8 @@ func (c *PDNSAPIClient) ListZones() (zones []pgo.Zone, resp *http.Response, err
 func (c *PDNSAPIClient) PartitionZones(zones []pgo.Zone) (filteredZones []pgo.Zone, residualZones []pgo.Zone) {
 	if c.domainFilter.IsConfigured() {
 		for _, zone := range zones {
-			if c.domainFilter.Match(zone.Name) || c.domainFilter.MatchParent(zone.Name) {
+			isMatch := c.domainFilter.Match(zone.Name)
+			if isMatch || (!c.domainFilter.IsRegexFilterConfigured() && c.domainFilter.MatchParent(zone.Name)) {
 				filteredZones = append(filteredZones, zone)
 			} else {
 				residualZones = append(residualZones, zone)

provider/pdns/pdns_test.go

@@ -20,6 +20,7 @@ import (
 	"context"
 	"errors"
 	"net/http"
+	"regexp"
 	"strings"
 	"testing"
 
@@ -513,6 +514,8 @@ var (
 		Filters: []string{},
 	}
 
+	RegexDomainFilter = endpoint.NewRegexDomainFilter(regexp.MustCompile("example.com"), nil)
+
 	DomainFilterEmptyClient = &PDNSAPIClient{
 		dryRun:       false,
 		authCtx:      context.WithValue(context.Background(), pgo.ContextAPIKey, pgo.APIKey{Key: "TEST-API-KEY"}),
@@ -547,6 +550,13 @@ var (
 		client:       pgo.NewAPIClient(pgo.NewConfiguration()),
 		domainFilter: DomainFilterChildListMultiple,
 	}
+
+	RegexDomainFilterClient = &PDNSAPIClient{
+		dryRun:       false,
+		authCtx:      context.WithValue(context.Background(), pgo.ContextAPIKey, pgo.APIKey{Key: "TEST-API-KEY"}),
+		client:       pgo.NewAPIClient(pgo.NewConfiguration()),
+		domainFilter: RegexDomainFilter,
+	}
 )
 
 /******************************************************************************/
@@ -1058,6 +1068,10 @@ func (suite *NewPDNSProviderTestSuite) TestPDNSClientPartitionZones() {
 	filteredZones, residualZones = DomainFilterChildMultipleClient.PartitionZones(zoneList)
 	assert.Equal(suite.T(), partitionResultFilteredMultipleFilter, filteredZones)
 	assert.Equal(suite.T(), partitionResultResidualMultipleFilter, residualZones)
+
+	filteredZones, residualZones = RegexDomainFilterClient.PartitionZones(zoneList)
+	assert.Equal(suite.T(), partitionResultFilteredSingleFilter, filteredZones)
+	assert.Equal(suite.T(), partitionResultResidualSingleFilter, residualZones)
 }
 
 func TestNewPDNSProviderTestSuite(t *testing.T) {