libnet: Endpoint: populate dnsNames on UnmarshalJSON

akerouanton · akerouanton · commit de2303b32dde · 2023-11-28T12:11:03.000+01:00
We need this to properly handle daemon upgrades.

Signed-off-by: Albin Kerouanton &lt;albinker@gmail.com&gt;
diff --git a/libnetwork/endpoint.go b/libnetwork/endpoint.go
@@ -200,11 +200,24 @@ func (ep *Endpoint) UnmarshalJSON(b []byte) (err error) {
 	json.Unmarshal(ma, &myAliases) //nolint:errcheck
 	ep.myAliases = myAliases
 
+	_, hasDNSNames := epMap["dnsNames"]
 	dn, _ := json.Marshal(epMap["dnsNames"])
 	var dnsNames []string
 	json.Unmarshal(dn, &dnsNames)
 	ep.dnsNames = dnsNames
 
+	if !hasDNSNames {
+		// The field dnsNames was introduced in v25.0. If we don't have it, the on-disk state was written by an older
+		// daemon, thus we need to populate dnsNames based off of myAliases and anonymous values.
+		var name string
+		if !ep.anonymous {
+			name = ep.name
+		}
+		// Hostname and id fields are purposefully left empty here as they should have been put into myAliases when the
+		// endpoint was originally created.
+		ep.dnsNames = BuildEndpointDNSNames(name, "", "", myAliases)
+	}
+
 	return nil
 }
 
