OJ-3387: Implement PDV / OTG healthcheck function

[barnabycollins]

Proposed changes

What changed

• Moved a number of utilities for getting information from the nino-check function into the common directory
• Added optional AbortSignal parameter to these utilities so they can be cancelled if they time out during the healthcheck
• Implemented healthcheck handler which asserts that the following are behaving as expected:
  • SSM param fetch
  • HMRC host
  • OTG token endpoint
  • PDV API
• Wrote IaC for healthcheck function and attached it to the public APIGW

Info endpoint response looks like this:

{
  "hmrcConfig": {
    "result": {
      "otg": {
        "apiUrl": "https://p2vx5z0kf7-vpce-05d20d011acdf9002.execute-api.eu-west-2.amazonaws.com/dev/token?tokenType=stub"
      },
      "pdv": {
        "apiUrl": "https://n7cz9mydma.execute-api.eu-west-2.amazonaws.com/dev/individuals/authentication/authenticator/api/match"
      }
    },
    "latency": 125
  },
  "hmrcHost": { "result": { "status": 403 }, "latency": 71 },
  "otg": { "result": { "tokenLength": 9 }, "latency": 163 },
  "pdv": { "result": { "status": 401 }, "latency": 68 }
}

Why did it change

• We want to be able to easily verify the integrity of the Check HMRC CRI's external dependencies

Issue tracking

• OJ-3387

Checklists

Environment variables or secrets

• No environment variables or secrets were added or changed

Other considerations

• Update README with any new instructions or tasks

[surajkumar]

LGTM - can you just add what the output of the /info looks like?

[barnabycollins]

LGTM - can you just add what the output of the /info looks like?

@surajkumar - added to PR description

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
93.8% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud