feat(ui): add structured JSON logging to all server-side routes and lib

Introduces a logger.ts module emitting slog-compatible JSON lines to stderr.
Replaces silent catch blocks and console.error calls throughout minio.ts,
pocketbase.ts, hooks.server.ts, login, books, browse, and all API routes so
auth/registration failures, MinIO presign errors, and scraper proxy failures
are now visible in container logs.

ui/src/hooks.server.ts

@@ -1,6 +1,7 @@
 import type { Handle } from '@sveltejs/kit';
 import { randomBytes, createHmac } from 'node:crypto';
 import { env } from '$env/dynamic/private';
+import { log } from '$lib/server/logger';
 
 const SESSION_COOKIE = 'libnovel_session';
 const AUTH_COOKIE = 'libnovel_auth';
@@ -80,7 +81,15 @@ export const handle: Handle = async ({ event, resolve }) => {
 
 	// Auth cookie → resolve logged-in user
 	const authToken = event.cookies.get(AUTH_COOKIE);
-	event.locals.user = authToken ? parseAuthToken(authToken) : null;
+	if (authToken) {
+		const user = parseAuthToken(authToken);
+		if (!user) {
+			log.warn('auth', 'auth cookie present but failed to parse (malformed or tampered)');
+		}
+		event.locals.user = user;
+	} else {
+		event.locals.user = null;
+	}
 
 	return resolve(event);
 };

ui/src/lib/server/logger.ts

@@ -0,0 +1,37 @@
+/**
+ * Structured server-side logger.
+ *
+ * Emits JSON lines to stderr so they appear in container/process logs without
+ * polluting stdout (which Node's HTTP layer uses for responses).
+ *
+ * Format mirrors Go's log/slog default JSON output:
+ *   {"time":"…","level":"ERROR","msg":"…","context":"pocketbase",...extra}
+ *
+ * Usage:
+ *   import { log } from '$lib/server/logger';
+ *   log.error('pocketbase', 'auth failed', { status: 401, url });
+ *   log.warn('minio', 'presign slow', { slug, n, ms: elapsed });
+ *   log.info('auth', 'user registered', { username });
+ */
+
+type Level = 'DEBUG' | 'INFO' | 'WARN' | 'ERROR';
+type Extra = Record<string, unknown>;
+
+function emit(level: Level, context: string, msg: string, extra?: Extra): void {
+	const entry: Record<string, unknown> = {
+		time: new Date().toISOString(),
+		level,
+		context,
+		msg,
+		...extra
+	};
+	// Write to stderr — never stdout
+	process.stderr.write(JSON.stringify(entry) + '\n');
+}
+
+export const log = {
+	debug: (context: string, msg: string, extra?: Extra) => emit('DEBUG', context, msg, extra),
+	info:  (context: string, msg: string, extra?: Extra) => emit('INFO',  context, msg, extra),
+	warn:  (context: string, msg: string, extra?: Extra) => emit('WARN',  context, msg, extra),
+	error: (context: string, msg: string, extra?: Extra) => emit('ERROR', context, msg, extra),
+};

ui/src/lib/server/minio.ts

@@ -8,6 +8,7 @@
 
 import { env } from '$env/dynamic/private';
 import { env as pubEnv } from '$env/dynamic/public';
+import { log } from '$lib/server/logger';
 
 const SCRAPER_URL = env.SCRAPER_API_URL ?? 'http://localhost:8080';
 // Public MinIO URL — used to rewrite presigned URLs so the browser can reach MinIO directly.
@@ -40,9 +41,21 @@ function rewriteHost(presignedUrl: string): string {
  * server-side (in a +page.server.ts load function) to fetch the markdown content.
  */
 export async function presignChapter(slug: string, n: number): Promise<string> {
-	const res = await fetch(`${SCRAPER_URL}/api/presign/chapter/${slug}/${n}`);
-	if (!res.ok) throw new Error(`presign chapter ${slug}/${n}: ${res.status}`);
+	log.debug('minio', 'presigning chapter', { slug, n });
+	let res: Response;
+	try {
+		res = await fetch(`${SCRAPER_URL}/api/presign/chapter/${slug}/${n}`);
+	} catch (e) {
+		log.error('minio', 'presign chapter network error', { slug, n, err: String(e) });
+		throw new Error(`presign chapter ${slug}/${n}: network error`);
+	}
+	if (!res.ok) {
+		const body = await res.text().catch(() => '');
+		log.error('minio', 'presign chapter failed', { slug, n, status: res.status, body });
+		throw new Error(`presign chapter ${slug}/${n}: ${res.status}`);
+	}
 	const data = (await res.json()) as { url: string };
+	log.debug('minio', 'presign chapter ok', { slug, n });
 	return rewriteHost(data.url);
 }
 
@@ -60,8 +73,20 @@ export async function presignAudio(
 	if (voice) params.set('voice', voice);
 	if (speed) params.set('speed', String(speed));
 	const qs = params.toString() ? `?${params.toString()}` : '';
-	const res = await fetch(`${SCRAPER_URL}/api/presign/audio/${slug}/${n}${qs}`);
-	if (!res.ok) throw new Error(`presign audio ${slug}/${n}: ${res.status}`);
+	log.debug('minio', 'presigning audio', { slug, n, voice, speed });
+	let res: Response;
+	try {
+		res = await fetch(`${SCRAPER_URL}/api/presign/audio/${slug}/${n}${qs}`);
+	} catch (e) {
+		log.error('minio', 'presign audio network error', { slug, n, err: String(e) });
+		throw new Error(`presign audio ${slug}/${n}: network error`);
+	}
+	if (!res.ok) {
+		const body = await res.text().catch(() => '');
+		log.error('minio', 'presign audio failed', { slug, n, status: res.status, body });
+		throw new Error(`presign audio ${slug}/${n}: ${res.status}`);
+	}
 	const data = (await res.json()) as { url: string };
+	log.debug('minio', 'presign audio ok', { slug, n });
 	return rewriteHost(data.url);
 }

ui/src/lib/server/pocketbase.ts

@@ -5,6 +5,7 @@
  */
 
 import { env } from '$env/dynamic/private';
+import { log } from '$lib/server/logger';
 
 const PB_URL = env.POCKETBASE_URL ?? 'http://localhost:8090';
 const PB_EMAIL = env.POCKETBASE_ADMIN_EMAIL ?? 'admin@libnovel.local';
@@ -58,6 +59,8 @@ let _tokenExp = 0;
 async function getToken(): Promise<string> {
 	if (_token && Date.now() < _tokenExp) return _token;
 
+	log.debug('pocketbase', 'authenticating with admin credentials', { url: PB_URL, email: PB_EMAIL });
+
 	const res = await fetch(`${PB_URL}/api/admins/auth-with-password`, {
 		method: 'POST',
 		headers: { 'Content-Type': 'application/json' },
@@ -65,12 +68,15 @@ async function getToken(): Promise<string> {
 	});
 
 	if (!res.ok) {
-		throw new Error(`PocketBase auth failed: ${res.status}`);
+		const body = await res.text().catch(() => '');
+		log.error('pocketbase', 'admin auth failed', { status: res.status, url: PB_URL, body });
+		throw new Error(`PocketBase auth failed: ${res.status} — ${body}`);
 	}
 
 	const data = await res.json();
 	_token = data.token as string;
 	_tokenExp = Date.now() + 12 * 60 * 60 * 1000; // 12 hours
+	log.info('pocketbase', 'admin auth token refreshed', { url: PB_URL });
 	return _token;
 }
 
@@ -81,7 +87,11 @@ async function pbGet<T>(path: string): Promise<T> {
 	const res = await fetch(`${PB_URL}${path}`, {
 		headers: { Authorization: token }
 	});
-	if (!res.ok) throw new Error(`PocketBase GET ${path} failed: ${res.status}`);
+	if (!res.ok) {
+		const body = await res.text().catch(() => '');
+		log.error('pocketbase', 'GET failed', { path, status: res.status, body });
+		throw new Error(`PocketBase GET ${path} failed: ${res.status} — ${body}`);
+	}
 	return res.json() as Promise<T>;
 }
 
@@ -103,10 +113,6 @@ async function pbPatch(path: string, body: unknown): Promise<Response> {
 	});
 }
 
-function encodeFilter(filter: string) {
-	return encodeURIComponent(filter);
-}
-
 interface PBList<T> {
 	items: T[];
 	totalItems: number;
@@ -170,9 +176,17 @@ export async function setProgress(sessionId: string, slug: string, chapter: numb
 	};
 
 	if (existing) {
-		await pbPatch(`/api/collections/progress/records/${existing.id}`, payload);
+		const res = await pbPatch(`/api/collections/progress/records/${existing.id}`, payload);
+		if (!res.ok) {
+			const body = await res.text().catch(() => '');
+			log.error('pocketbase', 'setProgress PATCH failed', { slug, chapter, status: res.status, body });
+		}
 	} else {
-		await pbPost('/api/collections/progress/records', payload);
+		const res = await pbPost('/api/collections/progress/records', payload);
+		if (!res.ok) {
+			const body = await res.text().catch(() => '');
+			log.error('pocketbase', 'setProgress POST failed', { slug, chapter, status: res.status, body });
+		}
 	}
 }
 
@@ -206,11 +220,14 @@ export async function getUserByUsername(username: string): Promise<User | null>
  * Create a new user with a hashed password. Throws if username already exists.
  */
 export async function createUser(username: string, password: string, role = 'user'): Promise<User> {
+	log.info('pocketbase', 'createUser: checking for existing username', { username });
 	const existing = await getUserByUsername(username);
 	if (existing) {
+		log.warn('pocketbase', 'createUser: username already taken', { username });
 		throw new Error('Username already taken');
 	}
 	const password_hash = hashPassword(password);
+	log.info('pocketbase', 'createUser: inserting new user', { username, role });
 	const res = await pbPost('/api/collections/users/records', {
 		username,
 		password_hash,
@@ -218,21 +235,33 @@ export async function createUser(username: string, password: string, role = 'use
 		created: new Date().toISOString()
 	});
 	if (!res.ok) {
-		const body = await res.text();
+		const body = await res.text().catch(() => '');
+		log.error('pocketbase', 'createUser: PocketBase rejected record', {
+			username,
+			status: res.status,
+			body
+		});
 		throw new Error(`Failed to create user: ${res.status} ${body}`);
 	}
+	log.info('pocketbase', 'createUser: user created', { username, role });
 	return res.json() as Promise<User>;
 }
 
 /**
  * Verify username + password. Returns the user on success, null on failure.
  */
-export async function loginUser(
-	username: string,
-	password: string
-): Promise<User | null> {
+export async function loginUser(username: string, password: string): Promise<User | null> {
+	log.debug('pocketbase', 'loginUser: lookup', { username });
 	const user = await getUserByUsername(username);
-	if (!user) return null;
-	if (!verifyPassword(password, user.password_hash)) return null;
+	if (!user) {
+		log.warn('pocketbase', 'loginUser: username not found', { username });
+		return null;
+	}
+	const ok = verifyPassword(password, user.password_hash);
+	if (!ok) {
+		log.warn('pocketbase', 'loginUser: wrong password', { username });
+		return null;
+	}
+	log.info('pocketbase', 'loginUser: success', { username, role: user.role });
 	return user;
 }

ui/src/routes/api/audio/[slug]/[n]/+server.ts

@@ -1,6 +1,7 @@
 import { error } from '@sveltejs/kit';
 import type { RequestHandler } from './$types';
 import { env } from '$env/dynamic/private';
+import { log } from '$lib/server/logger';
 
 const SCRAPER_URL = env.SCRAPER_API_URL ?? 'http://localhost:8080';
 
@@ -35,6 +36,7 @@ export const POST: RequestHandler = async ({ params, request }) => {
 
 	if (!scraperRes.ok) {
 		const text = await scraperRes.text().catch(() => '');
+		log.error('audio', 'scraper audio generation failed', { slug, chapter, status: scraperRes.status, body: text });
 		error(scraperRes.status as Parameters<typeof error>[0], text || 'Audio generation failed');
 	}
 
@@ -78,6 +80,7 @@ export const GET: RequestHandler = async ({ params, url }) => {
 	const scraperRes = await fetch(`${SCRAPER_URL}/api/audio-proxy/${slug}/${chapter}?${qs.toString()}`);
 
 	if (!scraperRes.ok) {
+		log.error('audio', 'scraper audio proxy failed', { slug, chapter, status: scraperRes.status });
 		error(scraperRes.status as Parameters<typeof error>[0], 'Audio not found');
 	}
 

ui/src/routes/api/presign/audio/+server.ts

@@ -1,6 +1,7 @@
 import { json, error } from '@sveltejs/kit';
 import type { RequestHandler } from './$types';
 import { presignAudio } from '$lib/server/minio';
+import { log } from '$lib/server/logger';
 
 /**
  * GET /api/presign/audio?slug=...&n=...&voice=...&speed=...
@@ -21,6 +22,7 @@ export const GET: RequestHandler = async ({ url }) => {
 		const presignedUrl = await presignAudio(slug, n, voice, speed);
 		return json({ url: presignedUrl });
 	} catch (e) {
+		log.error('presign', 'presign audio failed', { slug, n, err: String(e) });
 		error(500, `Could not get presigned URL: ${e}`);
 	}
 };

ui/src/routes/api/progress/+server.ts

@@ -1,6 +1,7 @@
 import { json, error } from '@sveltejs/kit';
 import type { RequestHandler } from './$types';
 import { setProgress } from '$lib/server/pocketbase';
+import { log } from '$lib/server/logger';
 
 /**
  * POST /api/progress
@@ -14,6 +15,11 @@ export const POST: RequestHandler = async ({ request, locals }) => {
 		error(400, 'Invalid body — expected { slug, chapter }');
 	}
 
-	await setProgress(locals.sessionId, body.slug, body.chapter);
+	try {
+		await setProgress(locals.sessionId, body.slug, body.chapter);
+	} catch (e) {
+		log.error('progress', 'setProgress failed', { slug: body.slug, chapter: body.chapter, err: String(e) });
+		error(500, 'Failed to save progress');
+	}
 	return json({ ok: true });
 };

ui/src/routes/api/scrape/+server.ts

@@ -18,6 +18,7 @@
 import { json, error } from '@sveltejs/kit';
 import type { RequestHandler } from './$types';
 import { env } from '$env/dynamic/private';
+import { log } from '$lib/server/logger';
 
 const SCRAPER_URL = env.SCRAPER_API_URL ?? 'http://localhost:8080';
 
@@ -39,11 +40,22 @@ export const POST: RequestHandler = async ({ request, locals }) => {
 	const endpoint = isBookScrape ? '/scrape/book' : '/scrape';
 
 	const upstream = `${SCRAPER_URL}${endpoint}`;
-	const res = await fetch(upstream, {
-		method: 'POST',
-		headers: { 'Content-Type': 'application/json' },
-		body: isBookScrape ? JSON.stringify({ url: body.url }) : undefined
-	});
+	let res: Response;
+	try {
+		res = await fetch(upstream, {
+			method: 'POST',
+			headers: { 'Content-Type': 'application/json' },
+			body: isBookScrape ? JSON.stringify({ url: body.url }) : undefined
+		});
+	} catch (e) {
+		log.error('scrape', 'scraper proxy network error', { endpoint, err: String(e) });
+		throw error(502, 'Could not reach scraper');
+	}
+
+	if (!res.ok && res.status >= 500) {
+		const text = await res.text().catch(() => '');
+		log.error('scrape', 'scraper returned error', { endpoint, status: res.status, body: text });
+	}
 
 	const data = await res.json().catch(() => ({}));
 

ui/src/routes/books/+page.server.ts

@@ -1,11 +1,21 @@
 import type { PageServerLoad } from './$types';
 import { listBooks, allProgress } from '$lib/server/pocketbase';
+import { log } from '$lib/server/logger';
 
 export const load: PageServerLoad = async ({ locals }) => {
-	const [books, progressList] = await Promise.all([
-		listBooks(),
-		allProgress(locals.sessionId)
-	]);
+	let books: Awaited<ReturnType<typeof listBooks>>;
+	let progressList: Awaited<ReturnType<typeof allProgress>>;
+
+	try {
+		[books, progressList] = await Promise.all([
+			listBooks(),
+			allProgress(locals.sessionId)
+		]);
+	} catch (e) {
+		log.error('books', 'failed to load books or progress', { err: String(e) });
+		books = [];
+		progressList = [];
+	}
 
 	// Build a quick lookup: slug → last chapter read
 	const progressMap: Record<string, number> = {};

ui/src/routes/books/[slug]/+page.server.ts

@@ -1,17 +1,28 @@
 import { error } from '@sveltejs/kit';
 import type { PageServerLoad } from './$types';
 import { getBook, listChapterIdx, getProgress } from '$lib/server/pocketbase';
+import { log } from '$lib/server/logger';
 
 export const load: PageServerLoad = async ({ params, locals }) => {
 	const { slug } = params;
 
-	const [book, chapters, progress] = await Promise.all([
-		getBook(slug),
-		listChapterIdx(slug),
-		getProgress(locals.sessionId, slug)
-	]);
+	let book: Awaited<ReturnType<typeof getBook>>;
+	let chapters: Awaited<ReturnType<typeof listChapterIdx>>;
+	let progress: Awaited<ReturnType<typeof getProgress>>;
+
+	try {
+		[book, chapters, progress] = await Promise.all([
+			getBook(slug),
+			listChapterIdx(slug),
+			getProgress(locals.sessionId, slug)
+		]);
+	} catch (e) {
+		log.error('books', 'failed to load book page', { slug, err: String(e) });
+		throw error(500, 'Failed to load book');
+	}
 
 	if (!book) {
+		log.warn('books', 'book not found', { slug });
 		error(404, `Book "${slug}" not found`);
 	}
 

ui/src/routes/books/[slug]/chapters/[n]/+page.server.ts

@@ -3,6 +3,7 @@ import { marked } from 'marked';
 import type { PageServerLoad } from './$types';
 import { getBook, listChapterIdx } from '$lib/server/pocketbase';
 import { presignChapter } from '$lib/server/minio';
+import { log } from '$lib/server/logger';
 
 export const load: PageServerLoad = async ({ params, locals }) => {
 	const { slug } = params;
@@ -28,7 +29,7 @@ export const load: PageServerLoad = async ({ params, locals }) => {
 		html = await marked(markdown, { async: true });
 	} catch (e) {
 		// Don't hard-fail — show empty content with error message
-		console.error('Failed to fetch chapter content:', e);
+		log.error('chapter', 'failed to fetch chapter content', { slug, n, err: String(e) });
 	}
 
 	const prevChapter = chapters.find((c) => c.number === n - 1) ?? null;

ui/src/routes/browse/+page.server.ts

@@ -1,6 +1,7 @@
 import { error } from '@sveltejs/kit';
 import type { PageServerLoad } from './$types';
 import { env } from '$env/dynamic/private';
+import { log } from '$lib/server/logger';
 
 const SCRAPER_URL = env.SCRAPER_API_URL ?? 'http://localhost:8080';
 
@@ -27,11 +28,13 @@ export const load: PageServerLoad = async ({ url, locals }) => {
 	try {
 		const res = await fetch(apiURL);
 		if (!res.ok) {
+			log.error('browse', 'scraper browse returned error', { status: res.status, url: apiURL });
 			throw error(502, `Browse fetch failed: ${res.status}`);
 		}
 		data = await res.json();
 	} catch (e) {
 		if (e instanceof Error && 'status' in e) throw e;
+		log.error('browse', 'scraper browse network error', { url: apiURL, err: String(e) });
 		throw error(502, 'Could not load browse page');
 	}
 

ui/src/routes/login/+page.server.ts

@@ -2,6 +2,7 @@ import { fail, redirect } from '@sveltejs/kit';
 import type { Actions, PageServerLoad } from './$types';
 import { loginUser, createUser } from '$lib/server/pocketbase';
 import { createAuthToken } from '../../hooks.server';
+import { log } from '$lib/server/logger';
 
 const AUTH_COOKIE = 'libnovel_auth';
 const ONE_YEAR = 60 * 60 * 24 * 365;
@@ -27,7 +28,8 @@ export const actions: Actions = {
 		let user;
 		try {
 			user = await loginUser(username, password);
-		} catch {
+		} catch (err) {
+			log.error('auth', 'login unexpected error', { username, err: String(err) });
 			return fail(500, { action: 'login', error: 'An error occurred. Please try again.' });
 		}
 
@@ -85,6 +87,7 @@ export const actions: Actions = {
 			if (msg.includes('Username already taken')) {
 				return fail(409, { action: 'register', error: 'That username is already taken.' });
 			}
+			log.error('auth', 'register unexpected error', { username, err: String(err) });
 			return fail(500, { action: 'register', error: 'An error occurred. Please try again.' });
 		}