Allow Træfik to know if a Host rule is malformed

provider/acme/provider.go

@@ -181,7 +181,7 @@ func (p *Provider) watchNewDomains() {
 						}
 
 						if len(domains) == 0 {
-							log.Debugf("No domain parsed in rule %q", route.Rule)
+							log.Debugf("No domain parsed in rule %q in provider ACME", route.Rule)
 							continue
 						}
 

rules/rules.go

@@ -9,7 +9,6 @@ import (
 	"sort"
 	"strings"
 
-	"github.com/BurntSushi/ty/fun"
 	"github.com/containous/mux"
 	"github.com/containous/traefik/types"
 )
@@ -270,9 +269,11 @@ func (r *Rules) Parse(expression string) (*mux.Route, error) {
 // ParseDomains parses rules expressions and returns domains
 func (r *Rules) ParseDomains(expression string) ([]string, error) {
 	var domains []string
+	isHostRule := false
 
 	err := r.parseRules(expression, func(functionName string, function interface{}, arguments []string) error {
 		if functionName == "Host" {
+			isHostRule = true
 			domains = append(domains, arguments...)
 		}
 		return nil
@@ -281,5 +282,18 @@ func (r *Rules) ParseDomains(expression string) ([]string, error) {
 		return nil, fmt.Errorf("error parsing domains: %v", err)
 	}
 
-	return fun.Map(types.CanonicalDomain, domains).([]string), nil
+	var cleanDomains []string
+	for _, domain := range domains {
+		canonicalDomain := types.CanonicalDomain(domain)
+		if len(canonicalDomain) > 0 {
+			cleanDomains = append(cleanDomains, canonicalDomain)
+		}
+	}
+
+	// Return an error if an Host rule is detected but no domain are parsed
+	if isHostRule && len(cleanDomains) == 0 {
+		return nil, fmt.Errorf("unable to parse correctly the domains in the Host rule from %q", expression)
+	}
+
+	return cleanDomains, nil
 }

rules/rules_test.go

@@ -54,24 +54,38 @@ func TestParseDomains(t *testing.T) {
 	rules := &Rules{}
 
 	tests := []struct {
-		expression string
-		domain     []string
+		description   string
+		expression    string
+		domain        []string
+		errorExpected bool
 	}{
 		{
-			expression: "Host:foo.bar,test.bar",
-			domain:     []string{"foo.bar", "test.bar"},
+			description:   "Many host rules",
+			expression:    "Host:foo.bar,test.bar",
+			domain:        []string{"foo.bar", "test.bar"},
+			errorExpected: false,
 		},
 		{
-			expression: "Path:/test",
-			domain:     []string{},
+			description:   "No host rule",
+			expression:    "Path:/test",
+			errorExpected: false,
 		},
 		{
-			expression: "Host:foo.bar;Path:/test",
-			domain:     []string{"foo.bar"},
+			description:   "Host rule and another rule",
+			expression:    "Host:foo.bar;Path:/test",
+			domain:        []string{"foo.bar"},
+			errorExpected: false,
 		},
 		{
-			expression: "Host: Foo.Bar ;Path:/test",
-			domain:     []string{"foo.bar"},
+			description:   "Host rule to trim and another rule",
+			expression:    "Host: Foo.Bar ;Path:/test",
+			domain:        []string{"foo.bar"},
+			errorExpected: false,
+		},
+		{
+			description:   "Host rule with no domain",
+			expression:    "Host: ;Path:/test",
+			errorExpected: true,
 		},
 	}
 
@@ -81,7 +95,12 @@ func TestParseDomains(t *testing.T) {
 			t.Parallel()
 
 			domains, err := rules.ParseDomains(test.expression)
-			require.NoError(t, err, "%s: Error while parsing domain.", test.expression)
+
+			if test.errorExpected {
+				require.Errorf(t, err, "unable to parse correctly the domains in the Host rule from %q", test.expression)
+			} else {
+				require.NoError(t, err, "%s: Error while parsing domain.", test.expression)
+			}
 
 			assert.EqualValues(t, test.domain, domains, "%s: Error parsing domains from expression.", test.expression)
 		})

server/server.go

@@ -676,9 +676,15 @@ func (s *Server) postLoadConfiguration() {
 						domains, err := rules.ParseDomains(route.Rule)
 						if err != nil {
 							log.Errorf("Error parsing domains: %v", err)
-						} else {
-							s.globalConfiguration.ACME.LoadCertificateForDomains(domains)
+							continue
 						}
+
+						if len(domains) == 0 {
+							log.Debugf("No domain parsed in rule %q", route.Rule)
+							continue
+						}
+
+						s.globalConfiguration.ACME.LoadCertificateForDomains(domains)
 					}
 				}
 			}