Naive HoneyComb OpenTelemetry Exporter WIP

package com.kenshoo.teddy.infra;

import com.google.inject.Singleton;
import io.honeycomb.libhoney.Event;
import io.honeycomb.libhoney.HoneyClient;
import io.honeycomb.libhoney.builders.HoneyClientBuilder;
import io.opentelemetry.sdk.trace.data.SpanData;
import io.opentelemetry.sdk.trace.export.SpanExporter;
import io.opentelemetry.trace.SpanId;

import java.time.Instant;
import java.util.Collection;
import java.util.Date;
import java.util.List;
import java.util.concurrent.TimeUnit;
import java.util.stream.Collectors;

/**
 * Created by: mosheeshel
 * Date: 2020-06-18 4:30 p.m.
 **/
public class HoneyCombSpanExporter implements SpanExporter {

    private HoneyClient honeyClient;

    public HoneyCombSpanExporter(String writeKey, String dataSet, String serviceName, String apiHost) {
        try {
            this.honeyClient = new HoneyClientBuilder()
                    .apiHost(apiHost)
                    .writeKey(writeKey)
                    .dataSet(dataSet)
                    .addGlobalField("service_name", serviceName)
                    .addGlobalField("meta.otel_exporter_version", "0.1")
                    .addGlobalField("meta.local_hostname", "host")
                    .build();
        } catch (Exception e) {

        }
    }

    public HoneyCombSpanExporter(String writeKey, String dataSet, String serviceName) {
        this(writeKey, dataSet, serviceName, "https://api.honeycomb.io");
    }

    @Override
    public ResultCode export(Collection<SpanData> spans) {
        try {
            convertSpansToEvents(spans)
                    .forEach(Event::send);
            return ResultCode.SUCCESS;
        } catch (Exception e) {
            return ResultCode.FAILURE;
        }
    }

    private List<Event> convertSpansToEvents(Collection<SpanData> spans) {
        return spans.stream()
                .map(this::convertSpanToEvent)
                .collect(Collectors.toList());
    }

    private Event convertSpanToEvent(SpanData spanData) {

        final long durationNS = spanData.getEndEpochNanos() - spanData.getStartEpochNanos();
        final long startEpochMs = TimeUnit.NANOSECONDS.toMillis(spanData.getStartEpochNanos());
        final Event event = honeyClient
                .createEvent()
                .setTimestamp(startEpochMs)
                .addField("trace.trace_id", spanData.getTraceId().toLowerBase16())
                .addField("trace.span_id", spanData.getSpanId().toLowerBase16())
                .addField("name", spanData.getName())
                .addField("start_time", Date.from(Instant.ofEpochSecond(startEpochMs)).toString())
                .addField("duration_ms", TimeUnit.NANOSECONDS.toMillis(durationNS))
                .addField("response.status_code", spanData.getStatus().getCanonicalCode().value())
                .addField("status.message", spanData.getStatus().getDescription())
                .addField("span.kind", spanData.getKind().name())
                .addFields(spanData.getAttributes());

        final SpanId parentSpanId = spanData.getParentSpanId();
        if (parentSpanId.isValid())
            event.addField("trace.parent_id", parentSpanId.toLowerBase16());

        if (!spanData.getStatus().isOk())
            event.addField("error", true);

        return event;
    }

    @Override
    public ResultCode flush() {

        return ResultCode.SUCCESS;
    }

    @Override
    public void shutdown() {
        honeyClient.close();
    }
}