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Class HealthCheckSetupExtensions ​

Namespace: Momentum.ServiceDefaults.HealthChecks
Assembly: Momentum.ServiceDefaults.dll

csharp
[ExcludeFromCodeCoverage]
public static class HealthCheckSetupExtensions

Inheritance ​

object ← HealthCheckSetupExtensions

Inherited Members ​

object.GetType(), object.MemberwiseClone(), object.ToString(), object.Equals(object?), object.Equals(object?, object?), object.ReferenceEquals(object?, object?), object.GetHashCode()

Methods ​

MapDefaultHealthCheckEndpoints(WebApplication) ​

Configures default health check endpoints for the application.

csharp
public static WebApplication MapDefaultHealthCheckEndpoints(this WebApplication app)

Parameters ​

app WebApplication

Returns ​

WebApplication

Remarks ​

Health Check Setup Extensions ​

Default Health Check Endpoints ​

This method sets up the following health check endpoints:

EndpointDescription
/statusA lightweight endpoint returning the status string of the last health check. Used for liveness probes. Note: This endpoint does not actually execute any health checks
/health/internalA container-only endpoint that returns simplified version health status information. Used for readiness probes in cloud environments. Locally, this endpoint will return the same information as the /health endpoint.
/healthA public endpoint requiring authorization that returns detailed health status information.

Endpoint Implementation Details ​

Liveness Probe - /status ​

csharp
app.MapGet("/status", () => healthCheckStore.LastHealthStatus.ToString())
    .ExcludeFromDescription();

Characteristics:

  • Lightweight: Returns cached status without executing checks
  • Fast Response: No I/O operations or health check execution
  • Kubernetes Compatible: Standard liveness probe format
  • Hidden from OpenAPI: Excluded from documentation

Readiness Probe - /health/internal ​

csharp
var isDevelopment = app.Environment.IsDevelopment();
app.MapHealthChecks("/health/internal",
        new HealthCheckOptions
        {
            ResponseWriter = (ctx, report) =>
                ProcessHealthCheckResult(ctx, logger, healthCheckStore, report, outputResult: isDevelopment)
        })
    .RequireHost("localhost")
    .AddEndpointFilter(new LocalhostEndpointFilter(logger));

Characteristics:

  • Environment Aware: Different responses for dev vs production
  • Localhost Only: Restricted to internal container access
  • Simplified Output: Production returns status string only
  • Detailed Development: Full report in development environment

Public Health Check - /health ​

csharp
app.MapHealthChecks("/health",
        new HealthCheckOptions
        {
            ResponseWriter = (ctx, report) =>
                ProcessHealthCheckResult(ctx, logger, healthCheckStore, report, outputResult: true)
        })
    .RequireAuthorization();

Characteristics:

  • Authorized Access: Requires authentication
  • Detailed Output: Full health check report
  • Public Facing: External monitoring system compatible
  • Comprehensive: Includes all check details and timing

Health Check Store Integration ​

Automatic Registration ​

csharp
var healthCheckStore = app.Services.GetService<HealthCheckStatusStore>() ?? new HealthCheckStatusStore();

This approach:

  • Simplifies Registration: Works without explicit DI registration
  • Enables Querying: Allows applications to check health status
  • Provides Caching: Stores last health check result

Status Tracking ​

csharp
healthCheckStore.LastHealthStatus = report.Status;

Benefits:

  • Cached Results: Liveness probe returns without execution
  • Performance: Eliminates redundant health check runs
  • Consistency: Same status across multiple endpoints

Response Processing ​

Conditional Output ​

csharp
private static Task ProcessHealthCheckResult(
    HttpContext httpContext,
    ILogger logger,
    HealthCheckStatusStore healthCheckStore,
    HealthReport report,
    bool outputResult)
{
    LogHealthCheckResponse(logger, report);
    healthCheckStore.LastHealthStatus = report.Status;

    return outputResult
        ? WriteReportObject(httpContext, report)
        : httpContext.Response.WriteAsync(report.Status.ToString());
}

Detailed Report Format ​

csharp
private static Task WriteReportObject(HttpContext context, HealthReport report)
{
    var response = new
    {
        Status = report.Status.ToString(),
        Duration = report.TotalDuration,
        Info = report.Entries
            .Select(e =>
                new
                {
                    e.Key,
                    e.Value.Description,
                    e.Value.Duration,
                    Status = Enum.GetName(e.Value.Status),
                    Error = e.Value.Exception?.Message,
                    e.Value.Data
                })
            .ToList()
    };

    return context.Response.WriteAsJsonAsync(response, options: JsonSerializerOptions);
}

Logging Integration ​

Structured Logging ​

csharp
[LoggerMessage(EventId = 1, Level = LogLevel.Debug, Message = "Health check response: {@HealthReport}")]
private static partial void LogSuccessfulHealthCheck(ILogger logger, HealthReport healthReport);

[LoggerMessage(EventId = 2, Message = "Health check failed: {FailedHealthReport}")]
private static partial void LogFailedHealthCheck(ILogger logger, LogLevel level, object failedHealthReport);

Health Status Logging ​

csharp
private static void LogHealthCheckResponse(ILogger logger, HealthReport report)
{
    if (report.Status is HealthStatus.Healthy)
    {
        LogSuccessfulHealthCheck(logger, report);
        return;
    }

    var logLevel = report.Status == HealthStatus.Unhealthy ? LogLevel.Error : LogLevel.Warning;

    var failedHealthReport = report.Entries.Select(e =>
        new { e.Key, e.Value.Status, e.Value.Duration, Error = e.Value.Exception?.Message });

    LogFailedHealthCheck(logger, logLevel, failedHealthReport);
}

JSON Serialization Configuration ​

Optimized Settings ​

csharp
private static readonly JsonSerializerOptions JsonSerializerOptions = new()
{
    WriteIndented = false,
    PropertyNamingPolicy = JsonNamingPolicy.CamelCase,
    DefaultIgnoreCondition = JsonIgnoreCondition.WhenWritingNull
};

Benefits:

  • Compact Output: No indentation for efficiency
  • Consistent Naming: camelCase for web standards
  • Clean Response: Omits null values

Security Considerations ​

Localhost Restriction ​

csharp
.RequireHost("localhost")
.AddEndpointFilter(new LocalhostEndpointFilter(logger))

Purpose:

  • Container Security: Prevents external access to internal endpoint
  • Network Isolation: Restricts to container networking
  • Attack Surface Reduction: Limits health check exposure

Authorization Requirement ​

csharp
.RequireAuthorization()

Benefits:

  • Access Control: Prevents unauthorized health monitoring
  • Information Security: Protects system status information
  • Compliance: Meets security audit requirements

Cloud Platform Integration ​

Kubernetes Health Checks ​

The endpoints integrate with Kubernetes probes:

yaml
livenessProbe:
  httpGet:
    path: /status
    port: 8080
  initialDelaySeconds: 30
  periodSeconds: 10

readinessProbe:
  httpGet:
    path: /health/internal
    port: 8080
  initialDelaySeconds: 5
  periodSeconds: 5

Docker Health Checks ​

dockerfile
HEALTHCHECK --interval=30s --timeout=3s --start-period=30s --retries=3 \
  CMD curl -f http://localhost:8080/status || exit 1

Performance Characteristics ​

Liveness Probe Performance ​

  • Sub-millisecond: Cached status lookup
  • No I/O: No database or external service calls
  • Minimal Allocation: String return only

Readiness Probe Performance ​

  • Environment Dependent: Fast in production, detailed in development
  • I/O Bound: Executes actual health checks
  • Comprehensive: Tests all registered health checks

Monitoring Integration ​

  • Structured Logs: Machine-readable health status
  • Metrics Compatible: Status codes for monitoring systems
  • Alert Friendly: Clear success/failure indicators

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