Bau/update logging config

[Joe-Edwards-GDS]

What

Updated log4j2 configuration to use JsonTemplateLayout

• JsonTemplateLayout provides fine-grained control over which fields are emitted, and e.g. allows us to omit irrelevant data
• The existing JsonLayout is 'considered deprecated'

See https://logging.apache.org/log4j/2.x/manual/json-template-layout.html for full documentation

Comparison

Existing log:

{
  "instant": {
    "epochSecond": 1760697868,
    "nanoOfSecond": 357164340
  },
  "thread": "JettyServerThreadPool-42",
  "level": "INFO",
  "loggerName": "uk.gov.di.authentication.frontendapi.services.StartService",
  "message": "Found UserStartInfo for Authenticated: false UpliftRequired: false IdentityRequired: false. CookieConsent: null. GATrackingId: null. IsBlockedForReauth: false",
  "endOfBatch": false,
  "loggerFqcn": "org.apache.logging.log4j.spi.AbstractLogger",
  "threadId": 42,
  "threadPriority": 5,
  "session-id": "3ixQF_KEweXmTmIHcSgecsx7VBg",
  "persistent-session-id": "ET46o9BABu_iMqo8Wr8ARzMdoeE--1755600903901",
  "client-session-id": "CMdfoFdhRZLHPf8rnHXzncvJ6eM",
  "govuk_signin_journey_id": "CMdfoFdhRZLHPf8rnHXzncvJ6eM",
  "client-id": "local-client-id"
}

New:

{
  "instant": {
    "epochSecond": 1760697141,
    "nanoOfSecond": 508495212
  },
  "level": "INFO",
  "loggerName": "uk.gov.di.authentication.frontendapi.services.StartService",
  "message": "Found UserStartInfo for Authenticated: false UpliftRequired: false IdentityRequired: false. CookieConsent: null. GATrackingId: null. IsBlockedForReauth: false",
  "session-id": "8ulo1PSYX3Mh8qeZ-HvsbC5QVEw",
  "persistent-session-id": "ET46o9BABu_iMqo8Wr8ARzMdoeE--1755600903901",
  "client-session-id": "5-arASqz61ZtLY7AasQ-akAHqNU",
  "govuk_signin_journey_id": "5-arASqz61ZtLY7AasQ-akAHqNU",
  "client-id": "local-client-id"
}

How to review

1. Code Review
2. [Optional] Deploy to dev env and check logs look suitable

I have already deployed to orch dev and checked some logs there (but not auth dev)

[Joe-Edwards-GDS]

In general this is based on https://github.com/apache/logging-log4j2/blob/rel/2.25.2/log4j-layout-template-json/src/main/resources/JsonLayout.json which mimics the output of JsonLayout.

We don't have to keep this - some things to consider:

• Changing the timestamp format to ISO-8601 for readability
• Removing client-session-id (if it's always the same as govuk_journey_id)

[CarlyG55]

I'd want to double check we are definitely setting the journey id everywhere - I'm pretty sure we are, but the team mostly currently rely on client-session-id for querying logs so there's a small chance it's not been added somewhere

[Joe-Edwards-GDS]

Cool - I'll probably leave it in for now, and let you tweak further as you like, hopefully it's fairly obvious how to update the config to do that!

(This specific file doesn't have it - because it's not logged in acct management API, but it should still be present in all the orch stuff)

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

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

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