'use strict';

​

const { EventHubConsumerClient, earliestEventPosition } = require('@azure/event-hubs');

const { ContainerClient } = require('@azure/storage-blob');

const { BlobCheckpointStore } = require('@azure/eventhubs-checkpointstore-blob');

​

const connectionString = process.env.AZURE_EVENTHUB_CONNECTION_STRING;

const partition_key = process.env.AZURE_EVENTHUB_PARTITION_KEY;

const eventHubName = process.env.AZURE_EVENTHUB_NAME;

const storageConnectionString = process.env.AZURE_BLOB_CONNECTION_STRING;

const containerName = process.env.AZURE_BLOB_CONTAINER_NAME;

const consumerGroup = '$Default'; // name of the default consumer group

var consumerClient = null;

var subscription = null;

​

const start_subscription = async () => {

  // Create a consumer client for the event hub by specifying the checkpoint store.

  const containerClient = new ContainerClient(storageConnectionString, containerName);

  const checkpointStore = new BlobCheckpointStore(containerClient);

  consumerClient = new EventHubConsumerClient(consumerGroup, connectionString, eventHubName, checkpointStore);

  const props = await consumerClient.getEventHubProperties();

  console.log(props.name);

  console.log(props.partitionIds);

  console.log('Start subscription.....');

  subscription = consumerClient.subscribe(

    {

      processEvents: async (events, context) => {

        if (events.length === 0) {

          console.log(`No events received within wait time. Waiting for next interval`);

          return;

        }

        events.forEach((event) => {

          console.log(`Received event: '${event.body}' from partition: '${context.partitionId}' and consumer group: '${context.consumerGroup}'`);

          console.dir(event.body);

        });

        // Update the checkpoint.

        await context.updateCheckpoint(events[events.length - 1]);

        return;

      },

      processError: async (error, context) => {

        console.error(`Error : ${err}`);

      },

    },

    { startPosition: earliestEventPosition }

  );

};

​

const stop_subscription = async () => {

  await subscription.close();

  await consumerClient.close();

  consumerClient = null;

  subscription = null;

  console.log('All subscriptions closed and cleaned up. Good job!');

};

​

module.exports = {

  start_subscription,

  stop_subscription,

};