Nucleus .Net Core CMS
  1. Instrumentation
  2. Health Checks
  3. Logging

Health Checks

Health checks are exposed by Nucleus as HTTP endpoints. Health checks can be used by load balancers and other infrastructure components to check the status of Nucleus on a server.

Health checks are not enabled by default. See the Configuration section below for instructions.

Three health checks are available:
Live Checks that Nucleus can respond to HTTP requests. The default endpoint is /_live. The Live check doesn't check anything, and always returns a Healthy status if Nucleus is running.
Ready Checks that Nucleus has completed its startup process. The default endpoint is /_ready. The Ready check returns a Degraded status while Nucleus is starting, and a Healthy status once Nucleus has started.
Health Performs a variety of health checks on Nucleus components. The default endpoint is /_health. The Health check calls all implementations of the IHealthCheck interface. Nucleus Core implements a number of health checks and extensions may provide additional health checks.

Output

The output from health check endpoints depends on the value of the HTTP request Accept header.

Header Value
text/html The output is a simple status (Healthy, Degraded or Unhealthy) in HTML - that is, wrapped with html and body tags.
application/health+json or application/json The output is in JSON format and includes a detailed list of failed checks (see below).
any other value The output is a simple status (Healthy, Degraded or Unhealthy) in text/plain format.

If you want to view the output from the Health endpoint, you will have to use a tool like Postman, so that you can set the value of the Accept header in your HTTP request. You can also use the curl command: curl https://your-site/_health --header "Accept:application/json"

The application/health+json output is intended to conform with the draft specification draft-inadarei-api-health-check-06. This specification has expired, but is the closest thing to a standard available. If the status is Degraded or Unhealthy, each check may contain a "additional-info" array with one or more elements which each contain a "summary" and "output" property. This is consistent with the specification, which allows for "Additional Keys" in section 4.10.

Sample Output

{
  "status": "warn",
  "description": "Health of www.my-site.com",
  "version": "1",
  "releaseId": "1.4.0.0",
  "checks": {
    "Nucleus.Core.Services.HealthChecks.ApplicationReadyHealthCheck": [
      {
        "status": "pass",
        "componentType": "component",
        "time": "2024-02-14T04:00:10.0805868Z"
      }
    ],
    "Nucleus.Core.Services.HealthChecks.DatabaseConnectionsHealthCheck": [
      {
        "status": "pass",
        "componentType": "component",
        "time": "2024-02-14T04:00:10.0824630Z"
      }
    ],
    "Nucleus.Core.Services.HealthChecks.SearchProvidersHealthCheck": [
      {
        "status": "warn",
        "componentType": "component",
        "time": "2024-02-14T04:00:10.0824794Z",
        "output": "One or more search index provider connection tests failed.",
        "additional-info": [
          {
            "summary": "Connection Error",
            "output": "Search index provider 'Nucleus.Extensions.ElasticSearch.SearchIndexManager' returned an error when connecting using the settings for site 'Second Site', and will not receive data."
          }
        ]
      }
    ]
  }
}

Built-in Health Checks

Database Connections

The Database Connections health check tests database connectivity for each configured database. If the connection test fails:

  • If the database belongs to the default schema *, an Unhealthy status is returned. This is because Nucleus cannot function when the default database is not working.
  • If the database belongs to another schema *, a Degraded status is returned. This is because Nucleus can generally function when a database that belongs to a specific extension (or set of extensions) is not working, although some parts of the system are likely to fail.

Search Index Providers

The Search Index health check performs a connection test for each configured search index provider. If the connection test fails, a Degraded status is returned. This is because Nucleus can function when search is not working.

Configuration

Health checks must be enabled in order to function. To enable health checks with default settings edit your appSettings.Production.json file, and add a section to the existing Nucleus section.

"Nucleus" {
  "HealthChecks": {
      "Enabled": true
    },
  ...
}

See also: Configuration Files

Other (optional) settings for Nucleus:HealthChecks are:
LiveCheckEndPoint (string) The local path of the live check endpoint. The default is /_live.
ReadyCheckEndPoint (string) The local path of the ready check endpoint. The default is /_ready.
HealthCheckEndPoint (string) The local path of the health check endpoint. The default is /_health.
RequireRoles (string) A comma-delimited list of roles which can access health checks. The default value is not set, which allows anonymous access.

In order to use authentication with the RequireRoles setting, the caller must sign their HTTP request. The Api Keys page has more information.

"Nucleus" {
  "HealthChecks": {
    "Enabled": true,
    "HealthCheckEndPoint": "/_health",
    "LiveCheckEndPoint": "/_live",
    "ReadyCheckEndPoint": "/_ready",
    "RequireRoles": "System Monitors,Load Balancers"
    },
  ...
}
Privacy Policy