From 2d0ff2bf84b9fb59bc79bc2c38a52957dbf3ebbe Mon Sep 17 00:00:00 2001
From: Rinjae <dearmai@dearmai.net>
Date: Thu, 27 Aug 2026 16:44:57 +0900
Subject: [PATCH] =?UTF-8?q?=ED=85=9C=ED=94=8C=EB=A6=BF=20=EC=97=94?=
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---
 .../apim/portal/apps/ReadinessController.java | 44 +++++++++++++++----
 1 file changed, 35 insertions(+), 9 deletions(-)

diff --git a/src/main/java/com/eactive/apim/portal/apps/ReadinessController.java b/src/main/java/com/eactive/apim/portal/apps/ReadinessController.java
index 125bb9f..230d425 100644
--- a/src/main/java/com/eactive/apim/portal/apps/ReadinessController.java
+++ b/src/main/java/com/eactive/apim/portal/apps/ReadinessController.java
@@ -10,14 +10,21 @@ import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
 import org.springframework.web.bind.annotation.GetMapping;
 import org.springframework.web.bind.annotation.RestController;
+import org.thymeleaf.spring5.SpringTemplateEngine;
 
 /**
  * Readiness probe.
  *
  * <p>Distinct from {@link HealthCheckController} (liveness — servlet alive?).
  * This endpoint validates both EMS and Gateway datasources via JDBC
- * {@code Connection.isValid(timeout)} to confirm the app is ready to serve
- * requests that depend on the database.
+ * {@code Connection.isValid(timeout)}, and the Thymeleaf {@link SpringTemplateEngine}
+ * configuration, to confirm the app is ready to serve real page requests.
+ *
+ * <p>The template-engine check exists because this controller bypasses view
+ * resolution entirely (plain {@code @RestController} JSON) — a broken
+ * {@code TemplateEngine.getConfiguration()} (e.g. classpath split causing
+ * {@link java.util.ServiceConfigurationError} during dialect/module discovery)
+ * previously left every real page returning 500 while this probe still reported 200.
  *
  * <p>HTTP 200 + JSON when all checks pass.
  * <p>HTTP 503 + JSON when any check fails — body still includes the per-component
@@ -30,24 +37,29 @@ public class ReadinessController {
 
     private final DataSource portalDataSource;
     private final DataSource gatewayDataSource;
+    private final SpringTemplateEngine templateEngine;
 
     public ReadinessController(
             @Qualifier("portalDataSource") DataSource portalDataSource,
-            @Qualifier("gatewayDataSource") DataSource gatewayDataSource) {
+            @Qualifier("gatewayDataSource") DataSource gatewayDataSource,
+            SpringTemplateEngine templateEngine) {
         this.portalDataSource = portalDataSource;
         this.gatewayDataSource = gatewayDataSource;
+        this.templateEngine = templateEngine;
     }
 
     @GetMapping(value = "/health/ready", produces = MediaType.APPLICATION_JSON_VALUE)
     public ResponseEntity<String> ready() {
-        String ems = check(portalDataSource);
-        String gw  = check(gatewayDataSource);
-        boolean ok = "UP".equals(ems) && "UP".equals(gw);
+        String ems  = check(portalDataSource);
+        String gw   = check(gatewayDataSource);
+        String view = checkTemplateEngine();
+        boolean ok = "UP".equals(ems) && "UP".equals(gw) && "UP".equals(view);
 
         String body = "{"
-                + "\"status\":\"" + (ok ? "UP" : "DOWN") + "\","
-                + "\"ems\":\""    + ems + "\","
-                + "\"gateway\":\""+ gw  + "\""
+                + "\"status\":\""  + (ok ? "UP" : "DOWN") + "\","
+                + "\"ems\":\""     + ems  + "\","
+                + "\"gateway\":\"" + gw   + "\","
+                + "\"view\":\""    + view + "\""
                 + "}";
 
         return ResponseEntity.status(ok ? 200 : 503)
@@ -55,6 +67,20 @@ public class ReadinessController {
                 .body(body);
     }
 
+    /** {@code getConfiguration()} lazily runs Thymeleaf's dialect/module init on first call
+     *  and caches it — so this is cheap once healthy, and reproduces the exact failure path
+     *  a real page render would hit. Catches {@link Throwable}: init failures here have
+     *  surfaced as {@link Error} (ServiceConfigurationError), not just Exception. */
+    private String checkTemplateEngine() {
+        try {
+            templateEngine.getConfiguration();
+            return "UP";
+        } catch (Throwable t) {
+            String msg = t.getMessage() == null ? t.getClass().getSimpleName() : t.getMessage();
+            return "DOWN:" + msg.replace('"', '\'').replace('\n', ' ').replace('\r', ' ');
+        }
+    }
+
     private static String check(DataSource ds) {
         if (ds == null) return "DOWN:NO_DATASOURCE";
         try (Connection c = ds.getConnection()) {