Add live log viewer on Settings → Logs tab

Terminal-style real-time log viewer with:
- Log file selector (app, post-processing, acoustid, source reuse)
- Color-coded log levels (DEBUG gray, INFO blue, WARNING yellow, ERROR red)
- Level filter buttons (All/Debug/Info/Warn/Error)
- Auto-scroll with toggle, copy and clear buttons
- Live updates via WebSocket (2s polling, pushes new lines)
- Initial load fetches last 200 lines via REST API
- 1000-line display cap with oldest lines trimmed

Also fixes Advanced tab settings (Discovery Pool, Security, etc.) being
hidden inside collapsed Library Preferences section body — misplaced
closing div caused them to be invisible.

web_server.py

@@ -6256,6 +6256,75 @@ def handle_log_level():
             logger.error(f"Error getting log level: {e}")
             return jsonify({"success": False, "error": str(e)}), 500
 
+# ===========================
+# LIVE LOG VIEWER API
+# ===========================
+
+# In-memory ring buffer for live log streaming via WebSocket
+_live_log_buffer = []
+_live_log_buffer_lock = threading.Lock()
+_LIVE_LOG_BUFFER_MAX = 500
+
+
+@app.route('/api/logs/tail', methods=['GET'])
+def get_log_tail():
+    """Return the last N lines from a log file, optionally filtered by level."""
+    log_source = request.args.get('source', 'app')
+    lines = request.args.get('lines', 200, type=int)
+    lines = max(10, min(lines, 1000))
+    level_filter = request.args.get('level', '').upper()  # DEBUG, INFO, WARNING, ERROR or empty
+
+    log_map = {
+        'app': os.path.join('logs', 'app.log'),
+        'post_processing': os.path.join('logs', 'post_processing.log'),
+        'acoustid': os.path.join('logs', 'acoustid.log'),
+        'source_reuse': os.path.join('logs', 'source_reuse.log'),
+    }
+    log_path = log_map.get(log_source, log_map['app'])
+
+    result_lines = []
+    if os.path.exists(log_path):
+        try:
+            with open(log_path, 'r', encoding='utf-8', errors='replace') as f:
+                all_lines = f.readlines()
+            # Read more lines than requested so filtering has enough to work with
+            tail = all_lines[-(lines * 3):] if level_filter else all_lines[-lines:]
+            for line in tail:
+                stripped = line.rstrip()
+                if not stripped:
+                    continue
+                if level_filter and level_filter in ('DEBUG', 'INFO', 'WARNING', 'ERROR'):
+                    # Match lines like "2026-04-18 12:00:00 - name - INFO - message"
+                    if f' - {level_filter} - ' not in stripped:
+                        continue
+                result_lines.append(stripped)
+            # Trim to requested count after filtering
+            result_lines = result_lines[-lines:]
+        except Exception as e:
+            result_lines = [f'Error reading log file: {e}']
+
+    # Available log files
+    available = []
+    logs_dir = 'logs'
+    if os.path.isdir(logs_dir):
+        for fname in sorted(os.listdir(logs_dir)):
+            if fname.endswith('.log'):
+                fpath = os.path.join(logs_dir, fname)
+                size_kb = os.path.getsize(fpath) / 1024
+                available.append({
+                    'key': fname.replace('.log', ''),
+                    'file': fname,
+                    'size': f"{size_kb:.0f} KB" if size_kb < 1024 else f"{size_kb/1024:.1f} MB",
+                })
+
+    return jsonify({
+        'lines': result_lines,
+        'source': log_source,
+        'total': len(result_lines),
+        'available_logs': available,
+    })
+
+
 # ===========================
 # AUTOMATIONS API
 # ===========================
@@ -54390,6 +54459,69 @@ def _emit_tool_progress_loop():
         except Exception as e:
             logger.debug(f"Error emitting logs: {e}")
 
+def _emit_live_log_loop():
+    """Background thread that tails app.log and pushes new lines via WebSocket."""
+    _last_pos = {}  # {source: file_position}
+    _active_source = 'app'
+    log_map = {
+        'app': os.path.join('logs', 'app.log'),
+        'post_processing': os.path.join('logs', 'post_processing.log'),
+        'acoustid': os.path.join('logs', 'acoustid.log'),
+        'source_reuse': os.path.join('logs', 'source_reuse.log'),
+    }
+    while not globals().get('IS_SHUTTING_DOWN', False):
+        socketio.sleep(2)
+        try:
+            # Read which source clients want (stored by subscribe handler)
+            source = getattr(_emit_live_log_loop, '_source', 'app')
+            log_path = log_map.get(source, log_map['app'])
+            if not os.path.exists(log_path):
+                continue
+
+            file_size = os.path.getsize(log_path)
+            last_pos = _last_pos.get(source, 0)
+
+            # File was truncated or rotated
+            if file_size < last_pos:
+                last_pos = 0
+
+            if file_size == last_pos:
+                continue  # No new data
+
+            new_lines = []
+            with open(log_path, 'r', encoding='utf-8', errors='replace') as f:
+                f.seek(last_pos)
+                for line in f:
+                    stripped = line.rstrip()
+                    if stripped:
+                        new_lines.append(stripped)
+                _last_pos[source] = f.tell()
+
+            if new_lines:
+                # Cap at 50 lines per push to avoid flooding
+                socketio.emit('logs:live', {
+                    'lines': new_lines[-50:],
+                    'source': source,
+                })
+        except Exception as e:
+            logger.debug(f"Error in live log emitter: {e}")
+
+_emit_live_log_loop._source = 'app'
+
+
+@socketio.on('logs:subscribe')
+def handle_logs_subscribe(data):
+    """Client subscribes to live log stream with optional source."""
+    source = data.get('source', 'app')
+    _emit_live_log_loop._source = source
+    join_room('logs:live')
+
+
+@socketio.on('logs:unsubscribe')
+def handle_logs_unsubscribe(data):
+    leave_room('logs:live')
+
+
 @socketio.on('sync:subscribe')
 def handle_sync_subscribe(data):
     for pid in data.get('playlist_ids', []):
@@ -54680,7 +54812,9 @@ def start_runtime_services():
         socketio.start_background_task(_hydrabase_reconnect_loop)
         # API Rate Monitor — 1s push for speedometer gauges
         socketio.start_background_task(_emit_rate_monitor_loop)
-        print("WebSocket emitters started (Phase 1-7: global/dashboard/enrichment/tools/sync/automations/repair + rate monitor)")
+        # Live log tail — streams new log lines to the log viewer
+        socketio.start_background_task(_emit_live_log_loop)
+        print("WebSocket emitters started (Phase 1-7: global/dashboard/enrichment/tools/sync/automations/repair + rate monitor + live logs)")
 
         _runtime_started = True
 

webui/index.html

@@ -3843,6 +3843,7 @@
                         <button class="stg-tab" data-tab="library" onclick="switchSettingsTab('library')">Library</button>
                         <button class="stg-tab" data-tab="appearance" onclick="switchSettingsTab('appearance')">Appearance</button>
                         <button class="stg-tab" data-tab="advanced" onclick="switchSettingsTab('advanced')">Advanced</button>
+                        <button class="stg-tab" data-tab="logs" onclick="switchSettingsTab('logs')">Logs</button>
                     </div>
                     <!-- Settings Panels -->
                     <div class="settings-columns">
@@ -5484,6 +5485,8 @@
                                 </div>
                             </div>
 
+                            </div><!-- end Library Preferences body -->
+
                             <!-- Security Settings -->
                             <div class="settings-group" data-stg="advanced">
                                 <h3>🔒 Security</h3>
@@ -5750,8 +5753,6 @@
                                 </div>
                             </div>
 
-                            </div><!-- end Library Preferences body -->
-
                             <!-- Logging Settings -->
                             <div class="settings-group" data-stg="advanced">
                                 <h3>Logging</h3>
@@ -5847,6 +5848,44 @@
                         </div>
                     </div>
 
+                    <!-- ═══ LOGS TAB ═══ -->
+                    <div class="settings-group" data-stg="logs" style="max-width:100%;">
+                        <div class="log-viewer-header">
+                            <div class="log-viewer-controls">
+                                <select id="log-viewer-source" class="log-viewer-select" onchange="_logViewerChangeSource()">
+                                    <option value="app">app.log</option>
+                                    <option value="post_processing">post_processing.log</option>
+                                    <option value="acoustid">acoustid.log</option>
+                                    <option value="source_reuse">source_reuse.log</option>
+                                </select>
+                                <div class="log-viewer-filters">
+                                    <button class="log-filter-btn active" data-level="" onclick="_logViewerFilterLevel(this)">All</button>
+                                    <button class="log-filter-btn lvl-debug" data-level="DEBUG" onclick="_logViewerFilterLevel(this)">Debug</button>
+                                    <button class="log-filter-btn lvl-info" data-level="INFO" onclick="_logViewerFilterLevel(this)">Info</button>
+                                    <button class="log-filter-btn lvl-warning" data-level="WARNING" onclick="_logViewerFilterLevel(this)">Warn</button>
+                                    <button class="log-filter-btn lvl-error" data-level="ERROR" onclick="_logViewerFilterLevel(this)">Error</button>
+                                </div>
+                            </div>
+                            <div class="log-viewer-actions">
+                                <button class="log-action-btn" onclick="_logViewerCopy()" title="Copy visible logs">Copy</button>
+                                <button class="log-action-btn" onclick="_logViewerClear()" title="Clear display">Clear</button>
+                                <label class="log-autoscroll-label">
+                                    <input type="checkbox" id="log-viewer-autoscroll" checked>
+                                    Auto-scroll
+                                </label>
+                            </div>
+                        </div>
+                        <div class="log-viewer-terminal" id="log-viewer-terminal">
+                            <div class="log-viewer-lines" id="log-viewer-lines">
+                                <div class="log-line log-info">Initializing log viewer...</div>
+                            </div>
+                        </div>
+                        <div class="log-viewer-status">
+                            <span id="log-viewer-line-count">0 lines</span>
+                            <span id="log-viewer-live-indicator" class="log-live-dot">● Live</span>
+                        </div>
+                    </div>
+
                     <!-- Save Button -->
                     <div class="settings-actions">
                         <button class="save-button" id="save-settings">Save Settings</button>

webui/static/helper.js

@@ -3602,6 +3602,11 @@ const WHATS_NEW = {
     '2.32': [
         // --- April 18, 2026 ---
         { date: 'April 18, 2026' },
+        { title: 'Live Log Viewer', desc: 'New Logs tab on the Settings page — real-time terminal-style log viewer with color-coded log levels. Filter by DEBUG/INFO/WARNING/ERROR, switch between log files (app, post-processing, acoustid, source reuse), auto-scroll, copy, and clear. Live updates via WebSocket', page: 'settings' },
+        { title: 'ReplayGain Post-Processing', desc: 'Optional ReplayGain tag analysis during post-processing. Enable in Settings → Library → Post-Processing. Analyzes loudness via ffmpeg and writes track-level gain/peak tags. Runs before lossy copy so both files get tagged. Off by default' },
+        { title: 'Fix Your Albums Using Playlist Modal', desc: 'Albums in the Discover page "Your Albums" section now open with the proper album-style download modal instead of the playlist-style modal. Shows artist image, album art, and uses album download context for correct file organization', page: 'discover' },
+        { title: 'Fix Tool Help Modal Not Closable', desc: 'The help "?" modal on automation triggers/actions could not be closed if the Tools page hadn\'t been visited first. Close button, backdrop click, and Escape key now work from any page' },
+        { title: 'Fix Spotify OAuth Port Steal in Docker', desc: 'On fresh installs, Spotify auth probe silently started an HTTP server that stole port 8008 (crash loop) or bound loopback-only on 8888 (unreachable from host). Now skips the probe when no cached token exists' },
         { title: 'Genre Whitelist', desc: 'Filter junk genre tags (artist names, radio shows, playlist names) from enrichment. Enable strict mode in Settings → Library Preferences → Genre Whitelist. 272 curated default genres, fully customizable — add, remove, search, reset. Applied across all 10 enrichment sources. Off by default', page: 'settings' },
         { title: 'Per-Artist Watchlist Scan Source', desc: 'Override which metadata provider (Spotify, Deezer, Apple Music, Discogs) is used when scanning a specific watchlist artist for new releases. Source selector in the artist config modal only shows providers the artist has enrichment matches for. Global default unchanged unless explicitly overridden', page: 'watchlist' },
         { title: 'Standalone Full Refresh', desc: 'Full Refresh now works for SoulSync Standalone mode — clears all soulsync library records and rebuilds from audio file tags in the output folder. Previously did nothing for standalone users', page: 'tools' },

webui/static/script.js

@@ -5755,6 +5755,12 @@ function switchSettingsTab(tab) {
     if (tab === 'advanced' && typeof loadDbMaintenanceInfo === 'function') {
         try { loadDbMaintenanceInfo(); } catch (e) { }
     }
+    // Initialize live log viewer when switching to Logs tab
+    if (tab === 'logs') {
+        _logViewerInit();
+    } else {
+        _logViewerStop();
+    }
 }
 
 function toggleStgService(el) {
@@ -6974,6 +6980,139 @@ function _collectGenreWhitelist() {
     return _genreWhitelistCache;
 }
 
+// ── Live Log Viewer ──
+let _logViewerActive = false;
+let _logViewerFilter = '';
+let _logViewerSource = 'app';
+const _LOG_MAX_LINES = 1000;
+
+async function _logViewerInit() {
+    if (_logViewerActive) return;
+    _logViewerActive = true;
+    _logViewerSource = document.getElementById('log-viewer-source')?.value || 'app';
+
+    // Fetch initial tail
+    try {
+        const params = new URLSearchParams({ source: _logViewerSource, lines: 200 });
+        if (_logViewerFilter) params.set('level', _logViewerFilter);
+        const resp = await fetch(`/api/logs/tail?${params}`);
+        const data = await resp.json();
+        if (data.lines) {
+            const container = document.getElementById('log-viewer-lines');
+            if (container) {
+                container.innerHTML = '';
+                _logViewerAppendLines(data.lines);
+            }
+        }
+    } catch (e) {
+        console.warn('Failed to load initial logs:', e);
+    }
+
+    // Subscribe to live updates
+    if (typeof socket !== 'undefined' && socket && socket.connected) {
+        socket.emit('logs:subscribe', { source: _logViewerSource });
+        socket.on('logs:live', _logViewerOnLive);
+    }
+}
+
+function _logViewerStop() {
+    if (!_logViewerActive) return;
+    _logViewerActive = false;
+    if (typeof socket !== 'undefined' && socket) {
+        socket.off('logs:live', _logViewerOnLive);
+        socket.emit('logs:unsubscribe', {});
+    }
+}
+
+function _logViewerOnLive(data) {
+    if (!_logViewerActive || !data.lines) return;
+    if (data.source !== _logViewerSource) return;
+    const filtered = _logViewerFilter
+        ? data.lines.filter(l => l.includes(` - ${_logViewerFilter} - `))
+        : data.lines;
+    if (filtered.length > 0) _logViewerAppendLines(filtered);
+}
+
+function _logViewerAppendLines(lines) {
+    const container = document.getElementById('log-viewer-lines');
+    if (!container) return;
+    const autoScroll = document.getElementById('log-viewer-autoscroll')?.checked;
+    const terminal = document.getElementById('log-viewer-terminal');
+
+    for (const line of lines) {
+        const div = document.createElement('div');
+        div.className = 'log-line ' + _logViewerGetClass(line);
+        div.textContent = line;
+        container.appendChild(div);
+    }
+
+    // Trim old lines
+    while (container.children.length > _LOG_MAX_LINES) {
+        container.removeChild(container.firstChild);
+    }
+
+    // Update count
+    const countEl = document.getElementById('log-viewer-line-count');
+    if (countEl) countEl.textContent = `${container.children.length} lines`;
+
+    // Auto-scroll
+    if (autoScroll && terminal) {
+        terminal.scrollTop = terminal.scrollHeight;
+    }
+}
+
+function _logViewerGetClass(line) {
+    if (line.includes(' - DEBUG - ')) return 'log-debug';
+    if (line.includes(' - INFO - ')) return 'log-info';
+    if (line.includes(' - WARNING - ')) return 'log-warning';
+    if (line.includes(' - ERROR - ') || line.includes(' - CRITICAL - ')) return 'log-error';
+    return 'log-plain';
+}
+
+async function _logViewerChangeSource() {
+    _logViewerStop();
+    _logViewerSource = document.getElementById('log-viewer-source')?.value || 'app';
+    const container = document.getElementById('log-viewer-lines');
+    if (container) container.innerHTML = '<div class="log-line log-info">Loading...</div>';
+    await _logViewerInit();
+}
+
+function _logViewerFilterLevel(btn) {
+    document.querySelectorAll('.log-filter-btn').forEach(b => b.classList.remove('active'));
+    btn.classList.add('active');
+    _logViewerFilter = btn.dataset.level || '';
+    // Reload with filter
+    _logViewerStop();
+    const container = document.getElementById('log-viewer-lines');
+    if (container) container.innerHTML = '';
+    _logViewerInit();
+}
+
+function _logViewerCopy() {
+    const container = document.getElementById('log-viewer-lines');
+    if (!container) return;
+    const text = Array.from(container.children).map(el => el.textContent).join('\n');
+    if (navigator.clipboard && window.isSecureContext) {
+        navigator.clipboard.writeText(text).then(() => showToast('Logs copied', 'success'));
+    } else {
+        const ta = document.createElement('textarea');
+        ta.value = text;
+        ta.style.cssText = 'position:fixed;left:-9999px';
+        document.body.appendChild(ta);
+        ta.select();
+        document.execCommand('copy');
+        document.body.removeChild(ta);
+        showToast('Logs copied', 'success');
+    }
+}
+
+function _logViewerClear() {
+    const container = document.getElementById('log-viewer-lines');
+    if (container) container.innerHTML = '';
+    const countEl = document.getElementById('log-viewer-line-count');
+    if (countEl) countEl.textContent = '0 lines';
+}
+
 // ── Database Maintenance ──
 async function loadDbMaintenanceInfo() {
     try {

webui/static/style.css

@@ -17213,6 +17213,136 @@ body.helper-mode-active #dashboard-activity-feed:hover {
     color: #ef5350;
 }
 
+/* ── Live Log Viewer ── */
+.log-viewer-header {
+    display: flex;
+    justify-content: space-between;
+    align-items: center;
+    flex-wrap: wrap;
+    gap: 10px;
+    margin-bottom: 10px;
+}
+
+.log-viewer-controls {
+    display: flex;
+    align-items: center;
+    gap: 10px;
+    flex-wrap: wrap;
+}
+
+.log-viewer-select {
+    background: rgba(255, 255, 255, 0.06);
+    border: 1px solid rgba(255, 255, 255, 0.12);
+    border-radius: 6px;
+    color: #e0e0e0;
+    padding: 6px 10px;
+    font-size: 13px;
+    font-family: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', monospace;
+}
+
+.log-viewer-filters {
+    display: flex;
+    gap: 4px;
+}
+
+.log-filter-btn {
+    padding: 4px 10px;
+    border-radius: 4px;
+    border: 1px solid rgba(255, 255, 255, 0.1);
+    background: transparent;
+    color: rgba(255, 255, 255, 0.5);
+    font-size: 12px;
+    cursor: pointer;
+    transition: all 0.15s;
+}
+
+.log-filter-btn:hover { background: rgba(255, 255, 255, 0.06); color: #fff; }
+.log-filter-btn.active { background: rgba(255, 255, 255, 0.1); color: #fff; border-color: rgba(255, 255, 255, 0.25); }
+.log-filter-btn.lvl-debug.active { color: #888; border-color: #666; }
+.log-filter-btn.lvl-info.active { color: #4fc3f7; border-color: #4fc3f7; }
+.log-filter-btn.lvl-warning.active { color: #ffd54f; border-color: #ffd54f; }
+.log-filter-btn.lvl-error.active { color: #ef5350; border-color: #ef5350; }
+
+.log-viewer-actions {
+    display: flex;
+    align-items: center;
+    gap: 8px;
+}
+
+.log-action-btn {
+    padding: 4px 12px;
+    border-radius: 4px;
+    border: 1px solid rgba(255, 255, 255, 0.1);
+    background: transparent;
+    color: rgba(255, 255, 255, 0.6);
+    font-size: 12px;
+    cursor: pointer;
+    transition: all 0.15s;
+}
+
+.log-action-btn:hover { background: rgba(255, 255, 255, 0.08); color: #fff; }
+
+.log-autoscroll-label {
+    display: flex;
+    align-items: center;
+    gap: 4px;
+    font-size: 12px;
+    color: rgba(255, 255, 255, 0.5);
+    cursor: pointer;
+}
+
+.log-viewer-terminal {
+    background: #0a0a14;
+    border: 1px solid rgba(255, 255, 255, 0.08);
+    border-radius: 8px;
+    height: 520px;
+    overflow-y: auto;
+    overflow-x: hidden;
+    padding: 12px;
+    font-family: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', 'Courier New', monospace;
+    font-size: 12px;
+    line-height: 1.5;
+}
+
+.log-viewer-terminal::-webkit-scrollbar { width: 6px; }
+.log-viewer-terminal::-webkit-scrollbar-track { background: transparent; }
+.log-viewer-terminal::-webkit-scrollbar-thumb { background: rgba(255,255,255,0.12); border-radius: 3px; }
+
+.log-viewer-lines {
+    word-break: break-all;
+}
+
+.log-line {
+    padding: 1px 0;
+    white-space: pre-wrap;
+    word-break: break-all;
+}
+
+.log-debug { color: #666; }
+.log-info { color: #4fc3f7; }
+.log-warning { color: #ffd54f; }
+.log-error { color: #ef5350; font-weight: 500; }
+.log-plain { color: #aaa; }
+
+.log-viewer-status {
+    display: flex;
+    justify-content: space-between;
+    align-items: center;
+    margin-top: 6px;
+    font-size: 11px;
+    color: rgba(255, 255, 255, 0.35);
+}
+
+.log-live-dot {
+    color: #4caf50;
+    animation: log-pulse 2s ease-in-out infinite;
+}
+
+@keyframes log-pulse {
+    0%, 100% { opacity: 1; }
+    50% { opacity: 0.4; }
+}
+
 .config-options {
     display: flex;
     flex-direction: column;