flink-connector-influxdb/src/main/java/org/apache/flink/streaming/connectors/influxdb/InfluxDBSink.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.flink.streaming.connectors.influxdb;

import org.apache.flink.configuration.Configuration;
import org.apache.flink.streaming.api.functions.sink.RichSinkFunction;
import org.apache.flink.util.CollectionUtil;
import org.apache.flink.util.Preconditions;
import org.apache.flink.util.StringUtils;
import org.influxdb.InfluxDB;
import org.influxdb.InfluxDBFactory;
import org.influxdb.dto.Point;

import java.util.concurrent.TimeUnit;

/**
 * Sink to save data into a InfluxDB cluster.
 */
public class InfluxDBSink extends RichSinkFunction<InfluxDBPoint> {

    private transient InfluxDB influxDBClient;
    private final InfluxDBConfig influxDBConfig;

    /**
     * Creates a new {@link InfluxDBSink} that connects to the InfluxDB server.
     *
     * @param influxDBConfig The configuration of {@link InfluxDBConfig}
     */
    public InfluxDBSink(InfluxDBConfig influxDBConfig) {
        this.influxDBConfig = Preconditions.checkNotNull(influxDBConfig, "InfluxDB client config should not be null");
    }

    /**
     * Initializes the connection to InfluxDB by either cluster or sentinels or single server.
     */
    @Override
    public void open(Configuration parameters) throws Exception {
        super.open(parameters);

        influxDBClient = InfluxDBFactory.connect(influxDBConfig.getUrl(), influxDBConfig.getUsername(), influxDBConfig.getPassword());

        if (!influxDBClient.databaseExists(influxDBConfig.getDatabase())) {
            if(influxDBConfig.isCreateDatabase()) {
                influxDBClient.createDatabase(influxDBConfig.getDatabase());
            }
            else {
                throw new RuntimeException("This " + influxDBConfig.getDatabase() + " database does not exist!");
            }
        }

        influxDBClient.setDatabase(influxDBConfig.getDatabase());

        if (influxDBConfig.getBatchActions() > 0) {
            influxDBClient.enableBatch(influxDBConfig.getBatchActions(), influxDBConfig.getFlushDuration(), influxDBConfig.getFlushDurationTimeUnit());
        }

        if (influxDBConfig.isEnableGzip()) {

            influxDBClient.enableGzip();
        }
    }

    /**
     * Called when new data arrives to the sink, and forwards it to InfluxDB.
     *
     * @param dataPoint {@link InfluxDBPoint}
     */
    @Override
    public void invoke(InfluxDBPoint dataPoint, Context context) throws Exception {
        if (StringUtils.isNullOrWhitespaceOnly(dataPoint.getMeasurement())) {
            throw new RuntimeException("No measurement defined");
        }

        Point.Builder builder = Point.measurement(dataPoint.getMeasurement())
                .time(dataPoint.getTimestamp(), TimeUnit.MILLISECONDS);

        if (!CollectionUtil.isNullOrEmpty(dataPoint.getFields())) {
            builder.fields(dataPoint.getFields());
        }

        if (!CollectionUtil.isNullOrEmpty(dataPoint.getTags())) {
            builder.tag(dataPoint.getTags());
        }

        Point point = builder.build();
        influxDBClient.write(point);
    }

    @Override
    public void close() {
        if (influxDBClient.isBatchEnabled()) {
            influxDBClient.disableBatch();
        }
        influxDBClient.close();
    }
}