Support container in one network shared with current container

nginx.tmpl

@@ -1,3 +1,5 @@
+{{ $CurrentContainer := where $ "ID" .CurrentContainerID | first }}
+
 {{ define "upstream" }}
 	{{ if .Address }}
 		{{/* If we got the containers from swarm and this container's port is published to host, use host IP:PORT */}}
@@ -75,16 +77,24 @@ server {
 upstream {{ $host }} {
 {{ range $container := $containers }}
 	{{ $addrLen := len $container.Addresses }}
-	{{ $network := index $container.Networks 0 }}
-	{{/* If only 1 port exposed, use that */}}
-	{{ if eq $addrLen 1 }}
-		{{ $address := index $container.Addresses 0 }}
-		{{ template "upstream" (dict "Container" $container "Address" $address "Network" $network) }}
-	{{/* If more than one port exposed, use the one matching VIRTUAL_PORT env var, falling back to standard web port 80 */}}
-	{{ else }}
-		{{ $port := coalesce $container.Env.VIRTUAL_PORT "80" }}
-		{{ $address := where $container.Addresses "Port" $port | first }}
-		{{ template "upstream" (dict "Container" $container "Address" $address "Network" $network) }}
+
+	{{ range $knownNetwork := $CurrentContainer.Networks }}
+		{{ range $containerNetwork := $container.Networks }}
+			{{ if eq $knownNetwork.Name $containerNetwork.Name }}
+				## Can be connect with "{{ $containerNetwork.Name }}" network
+
+				{{/* If only 1 port exposed, use that */}}
+				{{ if eq $addrLen 1 }}
+					{{ $address := index $container.Addresses 0 }}
+					{{ template "upstream" (dict "Container" $container "Address" $address "Network" $containerNetwork) }}
+				{{/* If more than one port exposed, use the one matching VIRTUAL_PORT env var, falling back to standard web port 80 */}}
+				{{ else }}
+					{{ $port := coalesce $container.Env.VIRTUAL_PORT "80" }}
+					{{ $address := where $container.Addresses "Port" $port | first }}
+					{{ template "upstream" (dict "Container" $container "Address" $address "Network" $containerNetwork) }}
+				{{ end }}
+			{{ end }}
+		{{ end }}
 	{{ end }}
 {{ end }}
 }