オリジナル配信サイトに視聴者数を取得して表示する機能をコマンド一発で構築する

#!/bin/bash

# Specify the desired volume size in GiB as a command line argument. If not specified, default to 20 GiB.
SIZE=${1:-20}

# Get the ID of the environment host Amazon EC2 instance.
INSTANCEID=$(curl http://169.254.169.254/latest/meta-data/instance-id)
REGION=$(curl -s http://169.254.169.254/latest/meta-data/placement/availability-zone | sed 's/\(.*\)[a-z]/\1/')

# Get the ID of the Amazon EBS volume associated with the instance.
VOLUMEID=$(aws ec2 describe-instances \
  --instance-id $INSTANCEID \
  --query "Reservations[0].Instances[0].BlockDeviceMappings[0].Ebs.VolumeId" \
  --output text \
  --region $REGION)

# Resize the EBS volume.
aws ec2 modify-volume --volume-id $VOLUMEID --size $SIZE

# Wait for the resize to finish.
while [ \
  "$(aws ec2 describe-volumes-modifications \
    --volume-id $VOLUMEID \
    --filters Name=modification-state,Values="optimizing","completed" \
    --query "length(VolumesModifications)"\
    --output text)" != "1" ]; do
sleep 1
done

#Check if we're on an NVMe filesystem
if [[ -e "/dev/xvda" && $(readlink -f /dev/xvda) = "/dev/xvda" ]]
then
  # Rewrite the partition table so that the partition takes up all the space that it can.
  sudo growpart /dev/xvda 1

  # Expand the size of the file system.
  # Check if we're on AL2
  STR=$(cat /etc/os-release)
  SUB="VERSION_ID=\"2\""
  if [[ "$STR" == *"$SUB"* ]]
  then
    sudo xfs_growfs -d /
  else
    sudo resize2fs /dev/xvda1
  fi

else
  # Rewrite the partition table so that the partition takes up all the space that it can.
  sudo growpart /dev/nvme0n1 1

  # Expand the size of the file system.
  # Check if we're on AL2
  STR=$(cat /etc/os-release)
  SUB="VERSION_ID=\"2\""
  if [[ "$STR" == *"$SUB"* ]]
  then
    sudo xfs_growfs -d /
  else
    sudo resize2fs /dev/nvme0n1p1
  fi
fi

bash resize.sh 20

import { Duration, Stack, StackProps, RemovalPolicy } from 'aws-cdk-lib';
import { Construct } from 'constructs';
import { Table, BillingMode, AttributeType } from 'aws-cdk-lib/aws-dynamodb';
import { Rule, Schedule } from 'aws-cdk-lib/aws-events';
import { LambdaFunction } from 'aws-cdk-lib/aws-events-targets';
import { PolicyStatement } from 'aws-cdk-lib/aws-iam';
import { NodejsFunction } from "aws-cdk-lib/aws-lambda-nodejs";

export class IvsViewersCountCdkStack extends Stack {
  constructor(scope: Construct, id: string, props?: StackProps) {
    super(scope, id, props);

    // ①視聴者数保存用の DynamoDB テーブルを作成
    const ivsViewersCountTable = new Table(this, "ivsViewersCountTable", {
      billingMode: BillingMode.PAY_PER_REQUEST,
      partitionKey: { name: 'channel', type: AttributeType.STRING },
      sortKey: { name: 'time', type: AttributeType.NUMBER },
      removalPolicy: RemovalPolicy.DESTROY
    });

    // ②Lambda 関数を作成
    const ivsViewersCountFunction = new NodejsFunction(this, "ivsViewersCountFunction", {
      entry: "src/ivs-viewers-count-function.handler.ts",
      environment: {
          TABLE_NAME: ivsViewersCountTable.tableName
      }
    });

    // ③Lambda 関数に、　DynamoDB の R/W 権限を付与
    ivsViewersCountTable.grantReadWriteData(ivsViewersCountFunction);
    
    // ④Lambda 関数に、 IVS へのアクセス権限を付与
    ivsViewersCountFunction.addToRolePolicy(new PolicyStatement({
      resources: [
        'arn:aws:ivs:us-east-1:*:channel/*'
      ],
      actions: [
        'ivs:ListChannels',
        'ivs:ListStreams',
        'ivs:PutMetadata'
      ]
    }));

    // ⑤Lambda 関数の定期呼び出し用の EventBridge ルールを定義
    new Rule(this, "ivsViewersCountRule", {
      schedule: Schedule.rate(Duration.minutes(1)),
      targets: [
        new LambdaFunction(ivsViewersCountFunction)
      ]
    });
  }
}

import {
  IvsClient,
  ListChannelsCommand,
  ListStreamsCommand,
  PutMetadataCommand
} from '@aws-sdk/client-ivs'
import {
  DynamoDB,
  BatchWriteItemCommand,
  QueryCommand
} from '@aws-sdk/client-dynamodb'

let response: object;
const dynamodb = new DynamoDB({});
const ivs = new IvsClient({});

export const handler = async () => {
  const tableName = process.env.TABLE_NAME as string;
  const time = Date.now();
  const counts: { [key: string]: number } = {};

  try {
    // ①チャンネルを取得し、視聴者数を 0 で初期化
    const listChannels = new ListChannelsCommand({});
    const resListChannels = await ivs.send(listChannels);
    if (resListChannels.channels) {
      resListChannels.channels.forEach(channel => {
        if (channel.arn) {
          counts[channel.arn] = 0;
        }
      });
    };

    // ②実際に開始されたストリーミングを取得し、視聴者数を取得
    const listStreams = new ListStreamsCommand({});
    const resListStreams = await ivs.send(listStreams);
    if (resListStreams.streams) {
      resListStreams.streams.forEach((stream) => {
        if (stream.channelArn && stream.viewerCount) {
          counts[stream.channelArn] += stream.viewerCount
        };
      });
    };

    // ③ DynamoDB に書き込みするデータを整形
    const requestItems = Object.entries(counts).map((item) => ({
      PutRequest: {
        Item: {
          channel: { S: item[0] },
          time: { N: String(time) },
          count: { N: String(item[1]) },
        },
      },
    }));

    // ④ DynamoDB に書き込み
    const batchWriteItem = new BatchWriteItemCommand({
      RequestItems: {
        [tableName]: requestItems,
      },
    });
    await dynamodb.send(batchWriteItem);

    // ⑤ DynamoDB から直近5分間の視聴者数を取得
    const queries = requestItems.map(item => {
      return new QueryCommand({
        TableName: tableName,
        KeyConditionExpression: "channel = :channel",
        ExpressionAttributeValues: {
          ':channel': { S: item.PutRequest.Item.channel.S },
        },
        Limit: 5,
        ScanIndexForward: false
      });
    });

    const results = await Promise.all(
      queries.map(async (query) => {
        return await dynamodb.send(query);
      })
    );

    // ⑥視聴者数を Timed Metadata として IVS に送信
    results.forEach(result => {
      if (result.Items) {
        const input = {
          channelArn: result.Items[0].channel.S,
          metadata: result.Items.map(item => item.count.N).join(',')
        };

        const putMetadataCommand = new PutMetadataCommand(input);

        ivs.send(putMetadataCommand);
      }
    });

    response = {
      statusCode: 200,
      body: JSON.stringify(counts),
    };
  } catch(err) {
    console.log(err);
    return err;
  };

  return response;
};

cd ivs-viewers-count-cdk
npm i

cdk bootstrap

cdk deploy

Do you wish to deploy these changes (y/n)? y

✅  IvsViewersCountCdkStack

# ctrl + c でアプリケーションを停止してから
git checkout feature/add-viewers-count
npm run dev

cdk destroy

Are you sure you want to delete: IvsViewersCountCdkStack (y/n)? y

✅  IvsViewersCountCdkStack: destroyed