fix(auth): distinguish Endorser unavailability from auth rejection

Return 503 when Endorser cannot be reached and keep 401 for rejected JWTs, with clearer server-side diagnostics and generic client messages.

src/middleware/auth.ts

@@ -132,15 +132,38 @@ export async function requireEndorserAuth(
     return;
   }
 
-  const endorsed = await checkAuth(jwt);
-  if (!endorsed) {
-    console.log("[Auth] Endorser verification failed");
-    res.status(401).json({
+  const result = await checkAuth(jwt);
+  if (result.ok) {
+    next();
+    return;
+  }
+
+  const errorTime = new Date().toISOString();
+  const did = req.did ?? "(unknown)";
+
+  if (result.reason === "unavailable") {
+    console.log("[Auth] Endorser unavailable");
+    console.error(
+      "[Auth] Endorser auth check unavailable at",
+      errorTime + ", did:",
+      did
+    );
+    res.status(503).json({
       success: false,
-      message: "Unauthorized",
+      message:
+        "Authentication service unavailable. See server logs at " + errorTime,
     });
     return;
   }
 
-  next();
+  console.log("[Auth] Endorser verification failed");
+  console.error(
+    "[Auth] Endorser rejected JWT at",
+    errorTime + ", did:",
+    did
+  );
+  res.status(401).json({
+    success: false,
+    message: "Unauthorized. See server logs at " + errorTime,
+  });
 }

src/services/endorserClient.ts

@@ -3,6 +3,10 @@ import { errorMessage } from "../util/formatElapsed.js";
 
 const RATE_LIMITS_PATH = "/api/report/rateLimits";
 
+export type EndorserAuthResult =
+  | { ok: true }
+  | { ok: false; reason: "unauthorized" | "unavailable" };
+
 function rateLimitsUrl(): string {
   const base = ENDORSER_URL.replace(/\/+$/, "");
   return `${base}${RATE_LIMITS_PATH}`;
@@ -12,13 +16,15 @@ function rateLimitsUrl(): string {
  * Confirms a JWT is accepted by the Endorser server.
  *
  * Calls GET /api/report/rateLimits with the JWT as a Bearer token.
- * Returns true on success, false on auth or request failure.
+ * Distinguishes auth rejection from Endorser unavailability.
  * Does not expose HTTP status or response bodies to callers.
  */
-export async function checkAuth(jwt: string): Promise<boolean> {
+export async function checkAuth(jwt: string): Promise<EndorserAuthResult> {
+  const url = rateLimitsUrl();
+
   let response: Response;
   try {
-    response = await fetch(rateLimitsUrl(), {
+    response = await fetch(url, {
       method: "GET",
       headers: {
         Authorization: `Bearer ${jwt}`,
@@ -26,19 +32,32 @@ export async function checkAuth(jwt: string): Promise<boolean> {
     });
   } catch (err) {
     console.error(
-      "[Endorser] Auth check request failed:",
+      "[Endorser] Auth check request failed for",
+      url + ":",
       errorMessage(err)
     );
-    return false;
+    return { ok: false, reason: "unavailable" };
   }
 
-  if (!response.ok) {
+  if (response.ok) {
+    return { ok: true };
+  }
+
+  // 5xx: Endorser is up but unhealthy; treat as unavailable.
+  if (response.status >= 500) {
     console.error(
-      "[Endorser] Auth check failed with status",
+      "[Endorser] Auth check unavailable for",
+      url + ", status",
       response.status
     );
-    return false;
+    return { ok: false, reason: "unavailable" };
   }
 
-  return true;
+  // 4xx: JWT rejected or user not registered on Endorser.
+  console.error(
+    "[Endorser] Auth check rejected for",
+    url + ", status",
+    response.status
+  );
+  return { ok: false, reason: "unauthorized" };
 }