w4c-workflows-api/Controllers/HealthController.cs

using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using StackExchange.Redis;
using w4c_workflows.Data;

namespace w4c_workflows.Controllers;

[ApiController]
public class HealthController : ControllerBase
{
    private readonly WorkflowsDbContext _db;
    private readonly IConnectionMultiplexer? _redis;

    // Redis is absent in Lite mode (in-memory transport). The dependency is
    // optional so liveness/readiness still resolve instead of failing DI.
    public HealthController(WorkflowsDbContext db, IConnectionMultiplexer? redis = null)
    {
        _db = db;
        _redis = redis;
    }

    /// <summary>Liveness — the process is up.</summary>
    [HttpGet("/health")]
    public IActionResult Health() => Ok(new { status = "ok" });

    /// <summary>Readiness — Postgres + Redis are reachable.</summary>
    [HttpGet("/health/ready")]
    public async Task<IActionResult> Ready(CancellationToken ct)
    {
        var checks = new Dictionary<string, string>();

        try
        {
            await _db.Database.CanConnectAsync(ct);
            checks["postgres"] = "ok";
        }
        catch (Exception ex)
        {
            checks["postgres"] = $"error: {ex.Message}";
        }

        try
        {
            checks["redis"] = _redis == null
                ? "not_configured"
                : (_redis.IsConnected ? "ok" : "disconnected");
        }
        catch (Exception ex)
        {
            checks["redis"] = $"error: {ex.Message}";
        }

        var healthy = checks.Values.All(v => v is "ok" or "not_configured");
        return healthy ? Ok(new { status = "ok", checks }) : StatusCode(503, new { status = "degraded", checks });
    }
}