似乎无法将 RDS 数据库实例指标传递到另一个堆栈

Question

我有2个堆栈，一个是我创建的RDS DB，另一个是用于cloudwatch警报。我试图从这里传递dbInstance的详细信息:

import * as cdk from 'aws-cdk-lib';
import * as ec2 from 'aws-cdk-lib/aws-ec2';
import * as rds from 'aws-cdk-lib/aws-rds';
import * as cloudwatch from 'aws-cdk-lib/aws-cloudwatch';
import { StackProps } from 'aws-cdk-lib';
import { IMetric } from 'aws-cdk-lib/aws-cloudwatch';

export class DatabaseStack extends cdk.Stack {
public readonly dbName: rds.DatabaseInstance
public readonly dbCPUUsage: IMetric
public readonly dbInstance: any;
constructor(scope: cdk.App, id: string, props?: cdk.StackProps) {
super(scope, id, props);
/*Created a VPC with a PUBLIC and an ISOLATED subnet groups.
RDS instance will be launched in an ISOLATED subnet because we'll be 
connecting to it from our EC2 instance, which is in the same VPC.*/
const vpc = new ec2.Vpc(this, 'my-cdk-vpc',{
...
});
const ec2InstanceSG = new ec2.SecurityGroup(this, 'ec2-instance-sg', {
vpc,
});
/*create security group for the EC2 instance with single inbound rule,
which allows SSH connections from anywhere.*/
ec2InstanceSG.addIngressRule(
ec2.Peer.anyIpv4(),
ec2.Port.tcp(22),
'allow SSH connections from anywhere',
);
//Created a t2.micro EC2 instance with Amazon Linux 2 AMI and placed it in a PUBLIC subnet.
const ec2Instance = new ec2.Instance(this, 'ec2-instance', {
...
});
/*Create RDS instance*/
const dbInstance = new rds.DatabaseInstance(this, 'db-instance',{
...
});
//allow connections to our RDS instance, on port 5432, from the security group of the EC2 instance
dbInstance.connections.allowFrom(ec2Instance, ec2.Port.tcp(5432));

//database hostname that we'll use to connect to our RDS instance
new cdk.CfnOutput(this, 'dbEndpoint', {
value:dbInstance.instanceEndpoint.hostname,
});
//name of the secret that stores the password of the postgres user
new cdk.CfnOutput(this, 'secretName', {
value: dbInstance.secret?.secretName!,
});
new cloudwatch.Alarm(this, 'HighCPU', {
metric: dbInstance.metricCPUUtilization(),
threshold: 100,
evaluationPeriods: 2,
})

this.dbName = dbInstance;
this.dbCPUUsage = dbInstance.metricCPUUtilization();
}
;
}
export interface CloudwatchStackProps extends StackProps {
dbNameExport: rds.IDatabaseInstance;
dbCPUUsageExport: IMetric;
};

到这个堆栈:

import * as cdk from 'aws-cdk-lib';
import * as cloudwatch from 'aws-cdk-lib/aws-cloudwatch';
import { IDatabaseInstance } from 'aws-cdk-lib/aws-rds';
import { Stack } from 'aws-cdk-lib';
import { CloudwatchStackProps } from '../lib/cdk-database-stack';
export class CloudwatchStack extends Stack {
private readonly dbInstance: IDatabaseInstance
constructor(scope: cdk.App, id: string, props: CloudwatchStackProps) {
super(scope, id, props);
const cpuUsage = props.dbCPUUsageExport
new cloudwatch.Alarm(this.dbInstance, 'CPUUsage', {
metric: cpuUsage(),
threshold: 100,
evaluationPeriods: 2,
});
}
}

我在做CDK Diff时得到的错误是"无法读取未定义的属性(读取'metric'))"。

本文件:

#!/usr/bin/env node
import * as cdk from 'aws-cdk-lib';
import { AmsAwsTestingGroundsStack } from '../lib/ams-aws-testing-grounds-stack';
import { CloudwatchStack } from '../lib/cdk-cloudwatch-stack';
import { DatabaseStack } from '../lib/cdk-database-stack';
const app = new cdk.App();
new AmsAwsTestingGroundsStack(app, 'AmsAwsTestingGroundsStack');
const databaseStack = new DatabaseStack(app, 'DatabaseStack');
const cloudwatchstack = new CloudwatchStack(app, 'CloudwatchStack', {
dbNameExport: databaseStack.dbName,
dbCPUUsageExport: databaseStack.dbCPUUsage,
});

任何帮助是感激和提前感谢你!

EDIT - solution

new cloudwatch.Alarm(this, 'CPUUsage', { 
metric: cpuUsage,
threshold: 100,
evaluationPeriods: 2,
});

Answer 1

我看到Alarm构造函数有两个问题:

new cloudwatch.Alarm(this, 'CPUUsage', { // <-- In a stack, `scope` should (almost) always be `this`
metric: cpuUsage, // <-- not callable, remove the ()
threshold: 100,
evaluationPeriods: 2,
});