How to find Index by Alias in Elasticsearch java api?

Question

Reindexing takes 30 seconds and I don't want my search to be offline for 30 seconds every time I need to reindex. I'm trying to do this:

1. Find old index with alias = abc123
2. Create new index and fill with new data
3. Remove alias and delete old index
4. Give new index alias = abc123

I can't seem to find any java code that does 1). Everything else is fine. Anyone? or is there another way that is better?

Using Elasticsearch 0.90.9.

Answer 1

Here is the method for your reference for finding all indices in a given aliasName:

public Set<String> getIndicesFromAliasName(String aliasName) {

    IndicesAdminClient iac = client.admin().indices();
    ImmutableOpenMap<String, List<AliasMetaData>> map = iac.getAliases(new GetAliasesRequest(aliasName))
            .actionGet().getAliases();

    final Set<String> allIndices = new HashSet<>();
    map.keysIt().forEachRemaining(allIndices::add);
    return allIndices;
}

Answer 2

You can use this to get all of the aliases:

 client.admin().cluster()
    .prepareState().execute()
    .actionGet().getState()
    .getMetaData().getAliases();

This returns a map with the index name as the key and the aliases as the value. So you can iterate over the map to get the index name.