Cluster Get Settings API

The Cluster Get Settings API allows to get the cluster wide settings.

Cluster Get Settings Request

A ClusterGetSettingsRequest:

ClusterGetSettingsRequest request = new ClusterGetSettingsRequest();

Optional arguments

The following arguments can optionally be provided:

request.includeDefaults(true); 

By default only those settings that were explicitly set are returned. Setting this to true also returns the default settings.

request.local(true); 

By default the request goes to the master of the cluster to get the latest results. If local is specified it gets the results from whichever node the request goes to.

request.masterNodeTimeout(TimeValue.timeValueMinutes(1)); 
request.masterNodeTimeout("1m"); 

Timeout to connect to the master node as a TimeValue

Timeout to connect to the master node as a String

Synchronous Execution

When executing a ClusterGetSettingsRequest in the following manner, the client waits for the ClusterGetSettingsResponse to be returned before continuing with code execution:

ClusterGetSettingsResponse response = client.cluster().getSettings(request, RequestOptions.DEFAULT); 

Synchronous calls may throw an IOException in case of either failing to parse the REST response in the high-level REST client, the request times out or similar cases where there is no response coming back from the server.

In cases where the server returns a 4xx or 5xx error code, the high-level client tries to parse the response body error details instead and then throws a generic ElasticsearchException and adds the original ResponseException as a suppressed exception to it.

Asynchronous Execution

Executing a ClusterGetSettingsRequest can also be done in an asynchronous fashion so that the client can return directly. Users need to specify how the response or potential failures will be handled by passing the request and a listener to the asynchronous get-settings method:

client.cluster().getSettingsAsync(request, RequestOptions.DEFAULT, listener); 

The ClusterGetSettingsRequest to execute and the ActionListener to use when the execution completes

The asynchronous method does not block and returns immediately. Once it is completed the ActionListener is called back using the onResponse method if the execution successfully completed or using the onFailure method if it failed. Failure scenarios and expected exceptions are the same as in the synchronous execution case.

A typical listener for get-settings looks like:

ActionListener<ClusterGetSettingsResponse> listener =
    new ActionListener<ClusterGetSettingsResponse>() {
        @Override
        public void onResponse(ClusterGetSettingsResponse response) {
            
        }

        @Override
        public void onFailure(Exception e) {
            
        }
    };

Called when the execution is successfully completed.

Called when the whole ClusterGetSettingsRequest fails.

Cluster Get Settings Response

The returned ClusterGetSettingsResponse allows to retrieve information about the executed operation as follows:

Settings persistentSettings = response.getPersistentSettings(); 
Settings transientSettings = response.getTransientSettings(); 
Settings defaultSettings = response.getDefaultSettings(); 
String settingValue = response.getSetting("cluster.routing.allocation.enable"); 

Get the persistent settings.

Get the transient settings.

Get the default settings (returns empty settings if includeDefaults was not set to true).

Get the value as a String for a particular setting. The order of searching is first in persistentSettings then in transientSettings and finally, if not found in either, in defaultSettings.