do A lookups after SRV lookups for store discovery

thanos-io · Mar 8, 2019 · 659366a · 659366a
1 parent b4d233e
commit 659366a
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Showing 2 changed files with 21 additions and 6 deletions.
diff --git a/pkg/discovery/dns/resolver.go b/pkg/discovery/dns/resolver.go
@@ -82,7 +82,14 @@ func (s *dnsSD) Resolve(ctx context.Context, name string, qtype QType) ([]string
 			if resPort == "" {
 				resPort = strconv.Itoa(int(rec.Port))
 			}
-			res = append(res, appendScheme(scheme, net.JoinHostPort(rec.Target, resPort)))
+			// Do A lookup for the domain in SRV answer
+			resIPs, err := s.resolver.LookupIPAddr(ctx, rec.Target)
+			if err != nil {
+				return nil, errors.Wrapf(err, "look IP addresses %q", rec.Target)
+			}
+			for _, resIP := range resIPs {
+				res = append(res, appendScheme(scheme, net.JoinHostPort(resIP.String(), resPort)))
+			}
 		}
 	default:
 		return nil, errors.Errorf("invalid lookup scheme %q", qtype)

diff --git a/pkg/discovery/dns/resolver_test.go b/pkg/discovery/dns/resolver_test.go
@@ -85,25 +85,33 @@ var (
 			resolver: &mockHostnameResolver{
 				resultSRVs: map[string][]*net.SRV{
 					"_test._tcp.mycompany.com": {
-						&net.SRV{Target: "192.168.0.1", Port: 8080},
-						&net.SRV{Target: "192.168.0.2", Port: 8081},
+						&net.SRV{Target: "alt1.mycompany.com.", Port: 8080},
+						&net.SRV{Target: "alt2.mycompany.com.", Port: 8081},
 					},
 				},
+				resultIPs: map[string][]net.IPAddr{
+					"alt1.mycompany.com.": {net.IPAddr{IP: net.ParseIP("192.168.0.1")}},
+					"alt2.mycompany.com.": {net.IPAddr{IP: net.ParseIP("192.168.0.2")}},
+				},
 			},
 		},
 		{
-			testName:       "multiple srv records from srv lookup",
+			testName:       "multiple srv records from srv lookup with specified port",
 			addr:           "_test._tcp.mycompany.com:8082",
 			qtype:          SRV,
 			expectedResult: []string{"192.168.0.1:8082", "192.168.0.2:8082"},
 			expectedErr:    nil,
 			resolver: &mockHostnameResolver{
 				resultSRVs: map[string][]*net.SRV{
 					"_test._tcp.mycompany.com": {
-						&net.SRV{Target: "192.168.0.1", Port: 8080},
-						&net.SRV{Target: "192.168.0.2", Port: 8081},
+						&net.SRV{Target: "alt1.mycompany.com.", Port: 8080},
+						&net.SRV{Target: "alt2.mycompany.com.", Port: 8081},
 					},
 				},
+				resultIPs: map[string][]net.IPAddr{
+					"alt1.mycompany.com.": {net.IPAddr{IP: net.ParseIP("192.168.0.1")}},
+					"alt2.mycompany.com.": {net.IPAddr{IP: net.ParseIP("192.168.0.2")}},
+				},
 			},
 		},
 		{