fix: migrate to AWS SDK v3

[rowanmanning]

This is important for several reasons:

1. AWS SDK v2 is no longer supported which is a risk. It also outputs very annoying deprecation warnings all the time

2. AWS SDK v2 is 98.1 MB!!! That's too big and it means that every single app that uses n-express will be installing aws-sdk regardless of whether it's actually used. The CloudWatch client is a still-not-great-but-much-better 1MB.

Testing locally

This is fairly easy to test locally. You need to get credentials for the FT Tech Infrastructure Prod AWS account and export them as environment variables. You can do this via AWS Login - click Access keys instead of FT-Engineer.

Now add the following to a new JavaScript file and run it via node. You should see health check output:

const alarmCheck = require('./main').runCheck({
	id: 'test-check-1',
	name: 'test check',
	severity: 1,
	businessImpact: 'Just a test',
	panicGuide: 'Just a test',
	technicalSummary: 'Just a test',
	type: 'cloudWatchAlarm',
	cloudWatchRegion: 'eu-west-1',
	cloudWatchAlarmName: 'ft-email_platform_tps_lookup-WriteCapacityUnitsLimit-BasicAlarm'
});

const thresholdCheck = require('./main').runCheck({
	id: 'test-check-2',
	name: 'test check',
	severity: 1,
	businessImpact: 'Just a test',
	panicGuide: 'Just a test',
	technicalSummary: 'Just a test',
	type: 'cloudWatchThreshold',
	cloudWatchRegion: 'eu-west-1',
	cloudWatchNamespace: 'AWS/ES',
	cloudWatchMetricName: 'ClusterStatus.yellow',
	cloudWatchStatistic: 'Average',
	cloudWatchDimensions: [
		{ Name: 'DomainName', Value: 'next-elasticsearch-v7' },
		{ Name: 'ClientId', Value: '027104099916' }
	],
	samplePeriod: 300,
	threshold: 0
});

setTimeout(() => {
	console.log(alarmCheck.getStatus());
	console.log(thresholdCheck.getStatus());
	process.exit(0);
}, 2000);

---

See-also: CPREL-1201

[alexmuller]

Nice! Really good size saving. This is giving the same output for me locally 👍