Health Checks

Overview

samber/do v2 does not expose health-check hooks in InjectorOpts. do-auditlog wraps injector.HealthCheckWithContext() to record EventTypeHealthCheck events per service.

Usage

// Instead of: err := injector.HealthCheckWithContext(ctx)
// Use the plugin wrapper:
err := plugin.RecordHealthCheckWithContext(ctx, injector)
if err != nil {
    log.Printf("health checks failed: %v", err)
}

report := plugin.Report()
if !report.HealthCheckSucceeded {
    for _, svc := range report.UnhealthyServices() {
        if svc.HealthCheckError != nil {
            log.Printf("unhealthy: %s — %s", svc.ServiceName, *svc.HealthCheckError)
        }
    }
}

How It Works

1. The plugin calls injector.HealthCheckWithContext(ctx) internally.
2. For each service that implements do.Healthchecker or do.HealthcheckerWithContext, a PhaseAfter health check event is recorded.
3. The event captures the service name, scope, and any error from the health check.
4. ServiceInfo.HealthCheckCount is incremented per check.
5. ServiceInfo.IsHealthchecker is set to true via do.ExplainInjector at report time.

Important Details

• PhaseAfter only: There is no interception point before the bulk health check runs, so there are no PhaseBefore events.
• No per-service timing: The bulk HealthCheckWithContext() API does not provide per-service duration. DurationMs is nil for health check events.
• HealthCheckSucceeded is false when no health checks ran: The report requires at least one health-checked service to report true.

Disabled Mode

When the plugin is disabled, RecordHealthCheck delegates directly to the injector without recording events:

plugin, _ := auditlog.New(auditlog.Config{
    Enabled: false,
})

// Still works — delegates to injector.HealthCheckWithContext(ctx)
err := plugin.RecordHealthCheckWithContext(ctx, injector)

Scope Resolution

The plugin resolves scope metadata from its internal serviceRecord map:

// Plugin.ResolveServiceScope resolves scope metadata by service name
// Handles both *do.RootScope and *do.Scope
scopeID, scopeName, found := plugin.ResolveServiceScope(scope, "*main.Database")