sync_live_channels.ts

import AWS = require("aws-sdk");
import { DateTime } from "luxon";

const dynamodb = new AWS.DynamoDB();
const kLiveChannelsTable = "live-channels";
const kLiveChannelConstantPartitionKey = "constant";
const kLiveChannelTTL = { minutes: 15 };

const fetchLiveChannels = async (
  cursor?: string,
): Promise<{ cursor?: string; channels: LiveChannel[] }> => {
  const client = await getExtensionClient();

  const result = await client.get(`live_activated_channels`, {
    query: { cursor },
  });

  return result.body;
};

export async function* getLiveChannels(): AsyncIterableIterator<LiveChannel[]> {
  let cursor: string | undefined;

  do {
    const result = await fetchLiveChannels(cursor);
    cursor = result.cursor;
    yield result.channels;
  } while (cursor);
}

const putLiveChannels = async (liveChannels: LiveChannel[]): Promise<void> => {
  if (liveChannels.length === 0) {
    return;
  }

  const ttl = DateTime.utc()
    .plus(kLiveChannelTTL)
    .toSeconds()
    .toFixed();

  await dynamodb
    .batchWriteItem({
      RequestItems: {
        [kLiveChannelsTable]: liveChannels.map(le => ({
          PutRequest: {
            Item: {
              key: { S: kLiveChannelConstantPartitionKey },
              id: { S: le.id },
              username: { S: le.username },
              game: { S: le.game },
              title: { S: le.title },
              view_count: { N: le.view_count },
              ttl: { N: ttl },
            },
          },
        })),
      },
    })
    .promise();
};

export const handler = main(async (event, context) => {
  const liveChannels = getLiveChannels();

  for await (const batch of liveChannels) {
    console.log(
      `Putting ${batch.length} items: ${batch.map(
        le => `${le.id}/${le.username}`,
      )}`,
    );

    await putLiveChannels(batch);
  }
});