How to get the instance hostname while running a Liberty App pushed via a Packaged Server

Question

I have a bluemix app pushed via packaged liberty server. The app looks for the instance IP/hostname internally. When the app is upscaled with more than one instance, using localhost as the hostname becomes obsolete. Host entry is set in our server.xml.

When i tried to use Referenceable variables such as ${host} or ${vcap_console_ip}, it is not getting the host name or ip address respectively.

1. ${host} returns 0.0.0.0 in our server.xml
2. ${vcap_console_ip} - it is not getting any value. I see the runtime-vars.xml doesn't show the ${vcap_console_ip} even if use it in the server.xml.

Looking for suggestion on how to get the host name or ip of the instance the app is running into my server.xml.

Answer 1

You could use the VCAP_APPLICATION env variable and get the "uris" attribute.

    String VCAP_APPLICATION = System.getenv("VCAP_APPLICATION");
    if (VCAP_APPLICATION != null) {
            JsonNode node = Json.mapper().readValue(VCAP_APPLICATION, JsonNode.class);
            ArrayNode uris = (ArrayNode) node.get("uris");
            if (uris != null && uris.size() > 0 && uris.get(0) != null) {
                host = uris.get(0).textValue();
            }