Disable exception alerting when service is disabled

[MatMoore]

Description

If SERVICE_ENABLED is false we put up a maintenence page which is a 503 response. This is considered an exception so it sets off our app insights exception alert.

Instead I was thinking we can just not enable this alert in this situation.

The rest of the alerts should still be enabled as the environment is still running regardless of whether the app is serving normal requests.

Jira link

Review notes

I moved locals.env_from_yaml to the top level in order to make the variables accessible in the infra module. Not sure if this is the best way to do it.

I wasn't particularly confident in my terraform-fu so I ran some terraform plans to check, and it will have the intended effect of destroying the appi-prod-uks-manbrs-exceptions-alert on prod.

The plan also includes some update-in-place stuff I wasn't expecting. Not sure where the drift has come from as it seems unrelated to my change - is it safe to ignore?

E.g. this one is being updated to match the devops templates, which has enabled_metric = ["AllMetrics"] `

  # module.container-apps[0].module.storage.module.diagnostic-settings["queueServices"].azurerm_monitor_diagnostic_setting.this will be updated in-place
  ~ resource "azurerm_monitor_diagnostic_setting" "this" {
        id                             = "/subscriptions/b3182f91-c8a7-4be0-be3e-0b34a95a48d7/resourceGroups/rg-manbrs-dev-container-app-uks/providers/Microsoft.Storage/storageAccounts/stmanbrsdevuks/queueServices/default|stmanbrsdevuks-diagnotic-setting-storage"
        name                           = "stmanbrsdevuks-diagnotic-setting-storage"
        # (5 unchanged attributes hidden)

      - enabled_metric {
          - category = "Capacity" -> null
        }
      - enabled_metric {
          - category = "Transaction" -> null
        }
      + enabled_metric {
          + category = "AllMetrics"
        }

        # (5 unchanged blocks hidden)
    }

  # module.container-apps[0].module.storage.module.diagnostic-settings["tableServices"].azurerm_monitor_diagnostic_setting.this will be updated in-place
  ~ resource "azurerm_monitor_diagnostic_setting" "this" {
        id                             = "/subscriptions/b3182f91-c8a7-4be0-be3e-0b34a95a48d7/resourceGroups/rg-manbrs-dev-container-app-uks/providers/Microsoft.Storage/storageAccounts/stmanbrsdevuks/tableServices/default|stmanbrsdevuks-diagnotic-setting-storage"
        name                           = "stmanbrsdevuks-diagnotic-setting-storage"
        # (5 unchanged attributes hidden)

      - enabled_metric {
          - category = "Capacity" -> null
        }
      - enabled_metric {
          - category = "Transaction" -> null
        }
      + enabled_metric {
          + category = "AllMetrics"
        }

        # (5 unchanged blocks hidden)
    }

Review checklist

• Check database queries are correctly scoped to current_provider
• If this changes the gateway API (/api/v1/), confirm whether it is a breaking change — if so, a new major version (/api/v2/) is required (see ADR-006)

[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

See analysis details on SonarQube Cloud