org.tarantool.cluster.TarantoolClusterStoredFunctionDiscoverer Maven / Gradle / Ivy

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package org.tarantool.cluster;

import org.tarantool.TarantoolClientImpl;
import org.tarantool.TarantoolClientOps;
import org.tarantool.TarantoolClusterClientConfig;
import org.tarantool.logging.Logger;
import org.tarantool.logging.LoggerFactory;
import org.tarantool.util.StringUtils;
import org.tarantool.util.TupleTwo;

import java.util.LinkedHashSet;
import java.util.List;
import java.util.Set;

/**
 * A cluster nodes discoverer based on calling a predefined function
 * which returns list of nodes.
 * 
 * The function has to have no arguments and return list of
 * the strings which follow host[:port] format
 * 

 * This class is not a part of public API.
 */
public class TarantoolClusterStoredFunctionDiscoverer implements TarantoolClusterDiscoverer {

    private static final Logger LOGGER = LoggerFactory.getLogger(TarantoolClusterStoredFunctionDiscoverer.class);

    private TarantoolClientImpl client;
    private String entryFunction;

    public TarantoolClusterStoredFunctionDiscoverer(TarantoolClusterClientConfig clientConfig,
                                                    TarantoolClientImpl client) {
        this.client = client;
        this.entryFunction = clientConfig.clusterDiscoveryEntryFunction;
    }

    @Override
    public Set getInstances() {
        TarantoolClientOps, Object, TupleTwo, Long>> syncOperations = client.unsafeSchemaOps();

        TupleTwo, Long> result = syncOperations.call(entryFunction);
        // discoverer expects a single array result from the function now;
        // in order to protect this contract the discoverer does a strict
        // validation against the data returned;
        // this strict-mode allows us to extend the contract in a non-breaking
        // way for old clients just reserve an extra return value in
        // terms of Lua multi-result support.;
        return checkAndFilterAddresses(result.getFirst());
    }

    /**
     * Check whether the result follows the contract or not.
     * The contract is a mandatory single array of strings.
     *
     * The simplified format for each string is host[:port].
     *
     * @param result result to be validated
     */
    private Set checkAndFilterAddresses(List result) {
        if (result == null || result.isEmpty()) {
            throw new IllegalDiscoveryFunctionResult("Discovery function returned no data");
        }
        if (!(result.get(0) instanceof List)) {
            throw new IllegalDiscoveryFunctionResult("The first value must be an array of strings");
        }

        LinkedHashSet passed = new LinkedHashSet<>();
        LinkedHashSet skipped = new LinkedHashSet<>();
        for (Object item : ((List