Java sample to backfill meters from MongoDB

<dependencies>
  <dependency>
    <groupId>io.amberflo</groupId>
    <artifactId>metering-java-client</artifactId>
    <version>1.3.6</version>
  </dependency>
  <dependency>
    <groupId>org.mongodb</groupId>
    <artifactId>mongo-java-driver</artifactId>
    <version>3.5.0</version>
  </dependency>
  <dependency>
    <groupId>com.stripe</groupId>
    <artifactId>stripe-java</artifactId>
    <version>20.52.0</version>
  </dependency>
</dependencies>

package com.amberflo.backfill;

import com.amberflo.metering.ingest.MeteringContext;
import com.amberflo.metering.ingest.meter_message.Domain;
import com.amberflo.metering.ingest.meter_message.MeterMessage;
import com.amberflo.metering.ingest.meter_message.MeterMessageBuilder;
import com.amberflo.metering.ingest.meter_message.Region;
import com.mongodb.MongoClient;
import com.mongodb.MongoClientURI;
import com.mongodb.client.FindIterable;
import com.mongodb.client.MongoCollection;
import com.mongodb.client.MongoCursor;
import com.mongodb.client.MongoDatabase;
import org.bson.Document;

import java.time.Instant;
import java.time.LocalDateTime;
import java.time.ZoneId;
import java.util.HashMap;
import java.util.Map;

import static com.amberflo.metering.ingest.MeteringContext.metering;

public class BackfillMongoDbData {
    //TODO: set the database connection, queries, and Amberflo info
    private static final String MONGO_HOST = "sample-db.mongo.host";
    private static final int MONGO_PORT = 27017;
    private static final String MONGO_USER = "sample-user";
    private static final String MONGO_PASS = "pass";
    private static final String DB_NAME = "sampleDb";
    private final static String AMBERFLO_API_KEY = "amberflo-api-key";
    //END TODO

    private final static String EVENT_CREATE = "event_create";

    public static void main(final String[] args) throws Exception {
        MeteringContext
                .createOrReplaceContext(
                        AMBERFLO_API_KEY,
                        "events-api",
                        Domain.Prod,
                        Region.US_West,
                        1,
                        10
                );

        // Mongodb connection string.
        final String connectionString = String.format("mongodb://%s:%s@%s:%s", MONGO_USER, MONGO_PASS, MONGO_HOST, MONGO_PORT);
        final MongoClientURI uri = new MongoClientURI(connectionString);

        // Connecting to the mongodb server using the given client uri.
        final MongoClient mongoClient = new MongoClient(uri);

        // Fetching the database from the mongodb.
        final MongoDatabase db = mongoClient.getDatabase(DB_NAME);

        // Fetching the collection from the mongodb.
        final MongoCollection<Document> col = db.getCollection("events");

        // Performing a read operation on the collection.
        final FindIterable<Document> fi = col.find();
        final MongoCursor<Document> cursor = fi.iterator();
        int counter = 1;
        try {
            while (cursor.hasNext()) {
                final Document document = cursor.next();
                if (document == null) {
                    continue;
                }
                //example of a nested document
                final Document eventData = (Document) document.get("eventData");
                final String eventSourceType = eventData.get("event_source_type").toString();
                final String eventType = eventData.get("event_type").toString();
                final String meterName = EVENT_CREATE;
                final String customerId = eventData.get("customer_id").toString();
                final String id = document.get("_id").toString();
                
                //Converting timestamp stored as double epoch
                final Long eventTimeEpoch = ((Double) Double.parseDouble(document.get("created_time_epoch_utc").toString())).longValue();
                final LocalDateTime eventTime = Instant.ofEpochMilli(eventTimeEpoch).atZone(ZoneId.of("UTC")).toLocalDateTime();

                System.out.println(String.format("Ingesting: event_source_type=%s, customerId=%s, id=%s, eventTime=%s, eventType=%s, meterName %s",
                        eventSourceType, customerId, id, eventTime, eventType, meterName));
                System.out.println(document.toJson());

                final Map<String, String> dimensions = new HashMap();
                dimensions.put("event_source_type", eventSourceType);
                dimensions.put("event_type", eventType);

                final MeterMessage meterMessage = MeterMessageBuilder
                        .createInstance(meterName, eventTime, customerId)
                        .setMeterValue(1)
                        .setUniqueId(id)
                        .setDimensionsMap(dimensions)
                        .build();

                metering().meter(meterMessage);

                if (counter % 100 == 0) {
                    Thread.sleep(5000);
                }
                counter++;
            }
            System.out.println("Total meters ingested: " + counter);
        } finally {
            cursor.close();
            mongoClient.close();
            MeteringContext.flushAndClose();
            System.out.println("done!");
        }
    }
}