health endpoint

backend/routes/health.js

@@ -0,0 +1,121 @@
+const express = require("express");
+const router = express.Router();
+const { sequelize } = require("../models");
+const s3Service = require("../services/s3Service");
+const logger = require("../utils/logger");
+
+/**
+ * Health check endpoint for load balancers and monitoring
+ * GET /health
+ *
+ * Returns:
+ * - 200: All services healthy
+ * - 503: One or more services unhealthy
+ */
+router.get("/", async (req, res) => {
+  const startTime = Date.now();
+  const checks = {
+    database: { status: "unknown", latency: null },
+    s3: { status: "unknown", latency: null },
+  };
+
+  let allHealthy = true;
+
+  // Database health check
+  try {
+    const dbStart = Date.now();
+    await sequelize.authenticate();
+    checks.database = {
+      status: "healthy",
+      latency: Date.now() - dbStart,
+    };
+  } catch (error) {
+    allHealthy = false;
+    checks.database = {
+      status: "unhealthy",
+      error: error.message,
+      latency: Date.now() - startTime,
+    };
+    logger.error("Health check: Database connection failed", {
+      error: error.message,
+    });
+  }
+
+  // S3 health check (if enabled)
+  if (s3Service.isEnabled()) {
+    try {
+      const s3Start = Date.now();
+      // S3 is considered healthy if it's properly initialized
+      // A more thorough check could list bucket contents, but that adds latency
+      checks.s3 = {
+        status: "healthy",
+        latency: Date.now() - s3Start,
+        bucket: process.env.S3_BUCKET,
+      };
+    } catch (error) {
+      allHealthy = false;
+      checks.s3 = {
+        status: "unhealthy",
+        error: error.message,
+        latency: Date.now() - startTime,
+      };
+      logger.error("Health check: S3 check failed", {
+        error: error.message,
+      });
+    }
+  } else {
+    checks.s3 = {
+      status: "disabled",
+      latency: 0,
+    };
+  }
+
+  // Log unhealthy states
+  if (!allHealthy) {
+    logger.warn("Health check failed", { checks });
+  }
+
+  res.status(allHealthy ? 200 : 503).json({
+    status: allHealthy ? "healthy" : "unhealthy",
+  });
+});
+
+/**
+ * Liveness probe - simple check that the process is running
+ * GET /health/live
+ *
+ * Used by Kubernetes/ECS for liveness probes
+ * Returns 200 if the process is alive
+ */
+router.get("/live", (req, res) => {
+  res.status(200).json({
+    status: "alive",
+    timestamp: new Date().toISOString(),
+  });
+});
+
+/**
+ * Readiness probe - check if the service is ready to accept traffic
+ * GET /health/ready
+ *
+ * Used by load balancers to determine if instance should receive traffic
+ * Checks critical dependencies (database)
+ */
+router.get("/ready", async (req, res) => {
+  try {
+    await sequelize.authenticate();
+    res.status(200).json({
+      status: "ready",
+      timestamp: new Date().toISOString(),
+    });
+  } catch (error) {
+    logger.error("Readiness check failed", { error: error.message });
+    res.status(503).json({
+      status: "not_ready",
+      timestamp: new Date().toISOString(),
+      error: "Database connection failed",
+    });
+  }
+});
+
+module.exports = router;