ln-774-healthcheck-setup

Type: L3 Worker Category: 7XX Project Bootstrap Parent: ln-770-crosscutting-setup

Configures health check endpoints for Kubernetes probes and monitoring.

Overview

Aspect	Details
Input	Context Store from ln-770
Output	Health check endpoints and Kubernetes probe configuration
Stacks	.NET (AspNetCore.Diagnostics.HealthChecks), Python (FastAPI routes)

Phase 1: Receive Context + Identify Dependencies

Accept Context Store and scan for dependencies to monitor.

Required Context:

```
STACK
```
: .NET or Python
```
PROJECT_ROOT
```
: Project directory path

Idempotency Check:

.NET: Grep for
```
AddHealthChecks
```
or
```
MapHealthChecks
```
Python: Grep for
```
/health
```
route
If found: Return
```
{ "status": "skipped" }
```

Dependency Detection:

Dependency	.NET Detection	Python Detection
PostgreSQL	`Npgsql` in csproj	`psycopg2` or `asyncpg` in requirements
MySQL	`MySql.Data` in csproj	`mysql-connector-python` in requirements
Redis	`StackExchange.Redis` in csproj	`redis` in requirements
RabbitMQ	`RabbitMQ.Client` in csproj	`pika` or `aio-pika` in requirements
MongoDB	`MongoDB.Driver` in csproj	`pymongo` in requirements

Phase 2: Design Health Check Strategy

Define three types of health endpoints per Kubernetes best practices.

Endpoint Types

Endpoint	Probe Type	Purpose	Checks
`/health/live`	Liveness	Is app alive?	App responds (no dependency checks)
`/health/ready`	Readiness	Can app serve traffic?	All dependencies healthy
`/health/startup`	Startup (K8s 1.16+)	Is app initialized?	Initial warmup complete

When Each Probe Fails

Probe	Failure Action	Kubernetes Behavior
Liveness	Container restart	kubelet restarts container
Readiness	Remove from service	Traffic stopped, no restart
Startup	Delay other probes	Liveness/Readiness paused

Phase 3: Research Health Check Patterns

Use MCP tools for current documentation.

For .NET:

MCP ref: "ASP.NET Core health checks Kubernetes probes"
Context7: /dotnet/aspnetcore

For Python:

MCP ref: "FastAPI health check endpoint Kubernetes"
Context7: /tiangolo/fastapi

Key Patterns to Research:

Database health checks (connection pool)
Redis connectivity check
Custom health check implementation
Health check response writer customization

Phase 4: Configure Kubernetes Probes

Determine probe timing based on application characteristics.

Probe Configuration

Parameter	Liveness	Readiness	Startup
`initialDelaySeconds`	10	5	0
`periodSeconds`	10	5	5
`timeoutSeconds`	5	3	3
`failureThreshold`	3	3	30
`successThreshold`	1	1	1

Startup Probe Calculation:

Max startup time = initialDelaySeconds + (periodSeconds × failureThreshold)
Default: 0 + (5 × 30) = 150 seconds

Phase 5: Generate Implementation

.NET Output Files

File	Purpose
`Extensions/HealthCheckExtensions.cs`	Health check registration
`HealthChecks/StartupHealthCheck.cs`	Custom startup check

Generation Process:

Use MCP ref for current ASP.NET Core health checks API
Generate HealthCheckExtensions with:
- AddHealthChecks registration
- Database health check (if detected)
- Redis health check (if detected)
- Custom StartupHealthCheck
Configure three endpoints with proper tags

Packages to Add:

```
AspNetCore.HealthChecks.NpgSql
```
(if PostgreSQL)
```
AspNetCore.HealthChecks.Redis
```
(if Redis)
```
AspNetCore.HealthChecks.MySql
```
(if MySQL)

Registration Code:

csharp

builder.Services.AddHealthCheckServices(builder.Configuration);
// ...
app.MapHealthCheckEndpoints();

Python Output Files

File	Purpose
`routes/health.py`	Health check router
`services/health_checker.py`	Dependency health checks

Generation Process:

Use MCP ref for FastAPI health patterns
Generate health router with:
- /health/live endpoint (simple)
- /health/ready endpoint (with dependency checks)
- /health/startup endpoint
Generate health_checker service for dependency verification

Registration Code:

python

from routes.health import health_router
app.include_router(health_router)

Kubernetes Manifest Snippet

Generate for inclusion in deployment.yaml:

yaml

livenessProbe:
  httpGet:
    path: /health/live
    port: 5000
  initialDelaySeconds: 10
  periodSeconds: 10
  timeoutSeconds: 5
  failureThreshold: 3

readinessProbe:
  httpGet:
    path: /health/ready
    port: 5000
  initialDelaySeconds: 5
  periodSeconds: 5
  timeoutSeconds: 3
  failureThreshold: 3

startupProbe:
  httpGet:
    path: /health/startup
    port: 5000
  periodSeconds: 5
  failureThreshold: 30

Phase 6: Validate

Validation Steps:

Syntax check:

.NET:
```
dotnet build --no-restore
```
Python:
```
python -m py_compile routes/health.py
```

Endpoint test:

bash

curl http://localhost:5000/health/live
curl http://localhost:5000/health/ready
curl http://localhost:5000/health/startup

Verify response format:

json

{
  "status": "Healthy",
  "checks": {
    "database": { "status": "Healthy", "duration": "00:00:00.0234" },
    "redis": { "status": "Healthy", "duration": "00:00:00.0012" }
  },
  "totalDuration": "00:00:00.0250"
}

Dependency failure test:
- Stop database
- Verify
```
/health/ready
```
  returns 503
- Verify
```
/health/live
```
  still returns 200

Return to Coordinator

json

{
  "status": "success",
  "files_created": [
    "Extensions/HealthCheckExtensions.cs",
    "HealthChecks/StartupHealthCheck.cs"
  ],
  "packages_added": [
    "AspNetCore.HealthChecks.NpgSql"
  ],
  "registration_code": "builder.Services.AddHealthCheckServices(configuration);",
  "message": "Configured health checks with liveness, readiness, and startup probes"
}

Reference Links

Version: 2.0.0 Last Updated: 2026-01-10

ln-774-healthcheck-setup

NPX Install

Tags

SKILL.md Content

ln-774-healthcheck-setup

Overview

Phase 1: Receive Context + Identify Dependencies

Phase 2: Design Health Check Strategy

Endpoint Types

When Each Probe Fails

Phase 3: Research Health Check Patterns

Phase 4: Configure Kubernetes Probes

Probe Configuration

Phase 5: Generate Implementation

.NET Output Files

Python Output Files

Kubernetes Manifest Snippet

Phase 6: Validate

Return to Coordinator

Reference Links