リザーブドインスタンスの有効期限切れを通知するためのスクリプト

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リザーブドインスタンスの有効期限切れを通知

で紹介している Lambda 関数

index.js

'use strict';

const AWS=require('aws-sdk');

const targetAccounts = [{
    accountName: "アカウント名",
    accountId: "アカウントID",
    remoteRole: "ロール名"
}];
const NOTIFY_TO_SNS_TOPIC = "SNSトピックのARN";
const MY_ACCOUNT_NAME = "自分のアカウント名";

const ALERT_DAYS = 14; // アラート発生日, 終了日の何日前に警告するかを指定
const S2MS = 1000;     // sec -> mill sec への変換係数
const SEC_OF_DAY = 24 * 60 * 60; // １日の秒数

/**
 * リザーブドインスタンス期限切れの確認
 */
exports.handler = async (event) => {
    console.log("start");
    console.log(JSON.stringify(event));

    // このアカウント
    let ec2 = new AWS.EC2();
    let rds = new AWS.RDS();

    try {
        console.log("check for own account");
        await checkReserveInstance(MY_ACCOUNT_NAME, ec2, rds);
    } catch(err) {
        console.error("error occured: " + JSON.stringify(err));
        console.log("continue...");
    }

    // リモートアカウント
    for (let accountInfo of targetAccounts) {
        console.log("check for account " + accountInfo.accountName);
        try {
            // STS 経由でcredentialsを取得
            let credentials = await getSTSCredential(accountInfo);
            let param = {
                accessKeyId : credentials.AccessKeyId,
                secretAccessKey : credentials.SecretAccessKey,
                sessionToken: credentials.SessionToken,
            };
            console.log("credentials from STS: " + JSON.stringify(param));

            ec2 = new AWS.EC2(param);
            rds = new AWS.RDS(param);

            await checkReserveInstance(accountInfo.accountName, ec2, rds);
        } catch(err) {
            console.error("error occured: " + JSON.stringify(err));
            console.log("continue...");    
        }
    }

    const response = {
        statusCode: 200,
        body: JSON.stringify('success'),
    };
    return response;
};

async function getSTSCredential(accountInfo) {
    const sts = new AWS.STS();

    let param = {
        RoleArn: "arn:aws:iam::" + accountInfo.accountId + ":role/" + accountInfo.remoteRole,
        RoleSessionName: "cross_account_by_lambda",
    };
    console.log("getSTSCredential param: " + JSON.stringify(param));
    return new Promise(function(resolve, reject) {
        sts.assumeRole(param, function(err, data) {
            if (err) {
                console.error("getSTSCredential: " + JSON.stringify(err));
                reject(err);
            } else {
                resolve(data.Credentials);
            }
        });
    });
}

async function checkReserveInstance(accountName, ec2, rds) {
    // EC2
    console.log("check EC2 RI");
    let endDates;
    try {
        endDates = await getEC2ReserveInstancesExpireDate(ec2);
        console.log("EC2 end dates: " + JSON.stringify(endDates));

        await notifyReservedInstanceExpire(accountName, endDates);
    } catch(err) {
        console.error("error occured for EC2 expire check: " + JSON.stringify(err));
    }

    // RDS
    console.log("check RDS RI");
    try {
        endDates = await getRDSReserveInstancesExpireDate(rds);
        console.log("RDS end dates: " + JSON.stringify(endDates));

        await notifyReservedInstanceExpire(accountName, endDates);
    } catch(err) {
        console.error("error occured for RDS expire check: " + JSON.stringify(err));            
    }    
}

async function notifyReservedInstanceExpire(accountName, endDates) {
    let nwDt = new Date();
    for (let cand of endDates) {
        let diffDays = (cand.endDate - nwDt) / S2MS / SEC_OF_DAY;
        if (diffDays <= ALERT_DAYS) {
            console.log("will expire, id: " + JSON.stringify(cand));
            await notifyViaSNS(accountName, cand);
        }
    }
}

async function getEC2ReserveInstancesExpireDate(ec2) {
    let result = [];
    let instances = await getActiveEC2ReserveInstances(ec2);
    console.log("active EC2 RIs:" + JSON.stringify(instances));

    for (let instance of instances.ReservedInstances) {
        let res = {
            resoruceType: "EC2",
            reservedInstanceId: instance.ReservedInstancesId,
            endDate: instance.End
        }
        result.push(res);
    }
    return result;
}

async function getActiveEC2ReserveInstances(ec2) {
    let param = {
        Filters: [{
            Name: "state",
            Values: ["active"]
        }],
    };
    console.log("getActiveEC2ReserveInstances param: " + JSON.stringify(param));

    return new Promise(function(resolve, reject) {
        ec2.describeReservedInstances(param, function(err, data){
            if (err) {
                console.error("describeReservedInstances: " + JSON.stringify(err));
                reject(err);
            } else {
                resolve(data);
            }
        });
    });
}

async function getRDSReserveInstancesExpireDate(rds) {
    let result = [];
    let instances = await getActiveRDSReserveInstances(rds);
    console.log("active RDS RIs:" + JSON.stringify(instances));

    for (let instance of instances) {
        let edDt = new Date(instance.StartTime);
        edDt.setDate(edDt.getDate() + (instance.Duration / SEC_OF_DAY));

        let res = {
            resoruceType: "RDS",
            reservedInstanceId: instance.ReservedDBInstanceId,
            endDate: edDt,
        }
        result.push(res);
    }
    return result;
}

async function getActiveRDSReserveInstances(rds) {
    let result = [];
    let data = await getRDSReserveInstances(rds);
    for (let instance of data.ReservedDBInstances ) {
        if (instance.State === "active") {
            result.push(instance);
        }
    }
    return result;
}
async function getRDSReserveInstances(rds) {
    return new Promise(function(resolve, reject) {
        rds.describeReservedDBInstances({}, function(err, data){
            if (err) {
                console.error("describeReservedDBInstances: " + JSON.stringify(err));
                reject(err);
            } else {
                resolve(data);
            }
        });
    });
}

async function notifyViaSNS(accountName, cand) {
    const sns = new AWS.SNS();

    let param = {
        Subject: "Reserved Instance will be expired soon.",
        Message: 
            "Account Name: " + accountName + 
            "\nResource Type: " + cand.resoruceType + 
            "\nReserved Instance Id: " + cand.reservedInstanceId + 
            "\nEnd date: " + cand.endDate,
        TopicArn: NOTIFY_TO_SNS_TOPIC,
    };
    console.log("notifyViaSNS param: " + JSON.stringify(param));

    return new Promise(function(resolve, reject) {
        sns.publish(param, function(err, data){
            if (err) {
                console.error("publish: " + JSON.stringify(err));
                reject(err);
            } else {
                resolve(data);
            }
        });
    });
}