How to get all indices with Elastic's High Level Rest Client?

heez :

I want a nice, quick and easy way to get all of the indices in elasticsearch using the their Java REST client. I am currently able to do this by grabbing their lower level client, like this:

public void fetchIndices() throws IOException {
    List<String> indices = null;

    RestClient restClient = client.getLowLevelClient();
    Response response = null;
    try {
        response = restClient.performRequest("GET", "/_cat/indices?v");
    } catch (IOException e) {
        LOGGER.log(Level.WARNING, e.toString(), e);
    }

    InputStream inputStream = null;
    if (response != null) {
        try {
            inputStream = response.getEntity().getContent();
        } catch (IOException e) {
            LOGGER.log(Level.WARNING, e.toString(), e);
        }
    }

    if (inputStream != null) {
        InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
        BufferedReader bufferedReader = new BufferedReader(inputStreamReader);

        indices = new ArrayList<>();
        String line;
        while ((line = bufferedReader.readLine()) != null) {
            // Get tokens with no whitespace
            String[] tokens = line.split("\\s+");
            for (String token : tokens) {
                // TODO - make the startsWith() token configurable
                if (token.startsWith(SOME_TOKEN)) {
                    LOGGER.log(Level.INFO, "Found elasticsearch index " + token);
                    indices.add(token);
                    break;
                }
            }
        }
    }

    // Only update if we got data back from our REST call
    if (indices != null) {
        this.indices = indices;
    }
}

Essentially I just call the /_cat/indices?v endpoint as recommended in their docs. This works fine, but I was wondering if there was a nicer way to do this using the Java API. I can't seem to find a way in their current API, but wondering if anyone knows something I don't. Having to work with InputStreams and the various Readers isn't necessarily terrible, but just want to clean up the hacky string parsing.

Mark Krijgsman :

As of Elasticsearch 7.5.0 you can use the following to retrieve all indices:

    GetIndexRequest request = new GetIndexRequest("*");
    GetIndexResponse response = client.indices().get(request, RequestOptions.DEFAULT);
    String[] indices = response.getIndices();