Fix: remove debug logging from nextauth

src/__tests__/pages/api/auth/[...nextauth].test.js

@@ -1,19 +1,29 @@
 import { beforeEach, describe, expect, it, vi } from "vitest";
 
-const { nextAuthMock } = vi.hoisted(() => ({
+const { debugMock, errorMock, nextAuthMock, warnMock } = vi.hoisted(() => ({
+  debugMock: vi.fn(),
+  errorMock: vi.fn(),
   nextAuthMock: vi.fn((options) => ({ options })),
+  warnMock: vi.fn(),
 }));
 
 vi.mock("next-auth", () => ({
   default: nextAuthMock,
 }));
 
+vi.mock("utils/logger", () => ({
+  default: vi.fn(() => ({ debug: debugMock, error: errorMock, warn: warnMock })),
+}));
+
 describe("pages/api/auth/[...nextauth]", () => {
   const originalEnv = process.env;
 
   beforeEach(() => {
     vi.resetModules();
+    debugMock.mockClear();
+    errorMock.mockClear();
     nextAuthMock.mockClear();
+    warnMock.mockClear();
     process.env = { ...originalEnv };
     delete process.env.NEXTAUTH_SECRET;
     delete process.env.NEXTAUTH_URL;
@@ -27,6 +37,50 @@ describe("pages/api/auth/[...nextauth]", () => {
     expect(mod.default.options.pages?.signIn).toBe("/auth/signin");
   });
 
+  it("does not enable NextAuth's raw debug logger", async () => {
+    const mod = await import("pages/api/auth/[...nextauth]");
+
+    expect(mod.default.options).not.toHaveProperty("debug");
+  });
+
+  it("routes sanitized NextAuth logs through the Homepage logger", async () => {
+    const mod = await import("pages/api/auth/[...nextauth]");
+    const sensitiveMetadata = {
+      clientSecret: "sensitive-client-secret",
+      access_token: "sensitive-access-token",
+      id_token: "sensitive-id-token",
+    };
+
+    mod.default.options.logger.error("OAUTH_CALLBACK_ERROR", sensitiveMetadata);
+    mod.default.options.logger.warn("NEXTAUTH_URL", sensitiveMetadata);
+    mod.default.options.logger.debug("OAUTH_CALLBACK_RESPONSE", sensitiveMetadata);
+
+    expect(errorMock).toHaveBeenCalledWith("%s", "OAUTH_CALLBACK_ERROR");
+    expect(warnMock).toHaveBeenCalledWith("%s", "NEXTAUTH_URL");
+    expect(debugMock).toHaveBeenCalledWith("%s", "OAUTH_CALLBACK_RESPONSE");
+    expect(JSON.stringify([...errorMock.mock.calls, ...warnMock.mock.calls, ...debugMock.mock.calls])).not.toContain(
+      "sensitive",
+    );
+  });
+
+  it("logs only sanitized authentication lifecycle events", async () => {
+    const mod = await import("pages/api/auth/[...nextauth]");
+
+    await mod.default.options.events.signIn({
+      account: {
+        provider: "homepage-oidc",
+        access_token: "sensitive-access-token",
+        id_token: "sensitive-id-token",
+      },
+      user: { email: "sensitive@example.com" },
+    });
+    await mod.default.options.events.signOut({ token: { sub: "sensitive-user-id" } });
+
+    expect(debugMock).toHaveBeenNthCalledWith(1, "Sign in via provider '%s'", "homepage-oidc");
+    expect(debugMock).toHaveBeenNthCalledWith(2, "Sign out");
+    expect(JSON.stringify(debugMock.mock.calls)).not.toContain("sensitive");
+  });
+
   it("maps HOMEPAGE_AUTH_SECRET and HOMEPAGE_EXTERNAL_URL to NextAuth envs", async () => {
     process.env.HOMEPAGE_AUTH_SECRET = "secret";
     process.env.HOMEPAGE_EXTERNAL_URL = "https://homepage.example";

src/pages/api/auth/[...nextauth].js

@@ -3,6 +3,8 @@ import { timingSafeEqual } from "node:crypto";
 import NextAuth from "next-auth";
 import CredentialsProvider from "next-auth/providers/credentials";
 
+import createLogger from "utils/logger";
+
 const authEnabled = Boolean(process.env.HOMEPAGE_AUTH_ENABLED);
 const issuer = process.env.HOMEPAGE_OIDC_ISSUER;
 const clientId = process.env.HOMEPAGE_OIDC_CLIENT_ID;
@@ -100,16 +102,15 @@ export const authOptions = {
   pages: {
     signIn: "/auth/signin",
   },
-  debug: true,
   logger: {
-    error: (...args) => console.error("[nextauth][error]", ...args),
-    warn: (...args) => console.warn("[nextauth][warn]", ...args),
-    debug: (...args) => console.debug("[nextauth][debug]", ...args),
+    error: (code) => createLogger("nextauth").error("%s", code),
+    warn: (code) => createLogger("nextauth").warn("%s", code),
+    debug: (code) => createLogger("nextauth").debug("%s", code),
   },
   events: {
-    signIn: async (message) => console.debug("[nextauth][event][signIn]", message),
-    signOut: async (message) => console.debug("[nextauth][event][signOut]", message),
-    error: async (message) => console.error("[nextauth][event][error]", message),
+    signIn: async ({ account }) =>
+      createLogger("nextauth").debug("Sign in via provider '%s'", account?.provider ?? "unknown"),
+    signOut: async () => createLogger("nextauth").debug("Sign out"),
   },
 };