ln-774-healthcheck-setup

Type: L3 Worker Category: 7XX Project Bootstrap

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:

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:

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

Kubernetes Manifest Snippet

Generate for inclusion in deployment.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:

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

Verify response format:

{ "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

{ "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

• ASP.NET Core Health Checks

• Kubernetes Probes

• AWS EKS Health Check Best Practices

Critical Rules

• Three separate endpoints — /health/live , /health/ready , /health/startup per Kubernetes best practices

• Liveness must not check dependencies — only confirms app is alive (avoids cascade restarts)

• Readiness checks all dependencies — DB, Redis, RabbitMQ connectivity verified

• Auto-detect dependencies from project files — scan csproj/requirements for known packages

• Idempotent — if AddHealthChecks /MapHealthChecks or /health route exists, return status: "skipped"

Definition of Done

• Context Store received (stack, project root)

• Dependencies detected (PostgreSQL, MySQL, Redis, RabbitMQ, MongoDB)

• Health check endpoints generated (live, ready, startup) for detected stack

• Kubernetes probe manifest snippet generated with proper timing parameters

• Syntax validated (dotnet build or py_compile )

• Structured JSON response returned to ln-770 coordinator

Version: 2.0.0 Last Updated: 2026-01-10