healthchecks-setup

Health Checks Setup

Add health checks that orchestrators can actually use: a liveness probe (am I alive?) separate from a readiness probe (can I serve traffic?), with dependency checks tagged correctly.

Input — point it at your project

Works on a target: a project or GitHub URL. Inspect: grep -rn "AddHealthChecks\|MapHealthChecks\|UseHealthChecks" --include=*.cs <target> and the dependencies in .csproj (DB/cache/broker) to know what to check.

Wiring (the live/ready split that matters)

builder.Services.AddHealthChecks()
    .AddNpgSql(conn, name: "db", tags: new[] { "ready" })
    .AddRedis(redisConn, name: "redis", tags: new[] { "ready" })
    .AddCheck("self", () => HealthCheckResult.Healthy(), tags: new[] { "live" });

// Liveness: is the process up? (no dependencies — don't restart on a DB blip)
app.MapHealthChecks("/health/live", new() { Predicate = c => c.Tags.Contains("live") });

// Readiness: can it serve? (include dependencies — pull from LB while a dep is down)
app.MapHealthChecks("/health/ready", new()
{
    Predicate = c => c.Tags.Contains("ready"),
    ResponseWriter = UIResponseWriter.WriteHealthCheckUIResponse   // JSON detail
});

Kubernetes probes

livenessProbe:  { httpGet: { path: /health/live,  port: 8080 }, periodSeconds: 10 }
readinessProbe: { httpGet: { path: /health/ready, port: 8080 }, periodSeconds: 5 }

Principles

• Liveness ≠ readiness. Liveness must NOT depend on the DB — a transient DB outage shouldn't restart your pods. Readiness should, so traffic is withheld until dependencies recover.
• Keep checks fast and cheap (timeouts); a slow health check causes flapping.
• Don't expose detailed health publicly without auth — it leaks topology.
• Add a check per critical dependency, tagged ready.

How to use it & best prompts

"Add health checks with liveness and readiness", "wire DB and Redis health", "Kubernetes probes for my service", "why does a DB blip restart my pods" (answer: liveness depends on DB — fix the split). Pairs with microservice-template-generator.