Add admin dashboard for session monitoring

- Create api/admin.py with /admin and /api/admin/sessions endpoints
- Add Bootstrap-styled templates/admin.html dashboard
- Auto-refresh every 10 seconds for real-time monitoring
- Shows session info, provider load, and summary stats

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

api/admin.py

@@ -0,0 +1,118 @@
+"""Admin dashboard for session monitoring."""
+
+import time
+from typing import Any
+
+from fastapi import APIRouter, Depends, Request
+from starlette.responses import HTMLResponse
+from starlette.templating import Jinja2Templates
+
+from core.session_tracker import SessionTracker
+
+from .dependencies import require_api_key
+
+router = APIRouter()
+
+templates = Jinja2Templates(directory="templates")
+
+
+def _get_blocked_providers() -> set[str]:
+    """Get currently blocked provider IDs. Placeholder - returns empty set."""
+    return set()
+
+
+def _format_time(seconds: float) -> str:
+    """Format seconds as human-readable string."""
+    if seconds < 60:
+        return f"{int(seconds)}s ago"
+    elif seconds < 3600:
+        return f"{int(seconds // 60)}m ago"
+    else:
+        return f"{int(seconds // 3600)}h ago"
+
+
+def _get_admin_data() -> dict[str, Any]:
+    """Gather all data for the admin dashboard."""
+    tracker = SessionTracker.get_instance()
+    blocked = _get_blocked_providers()
+
+    session_loads = tracker.get_all_session_loads()
+    provider_loads = tracker.get_all_provider_loads(blocked)
+
+    now = time.monotonic()
+
+    total_requests = 0
+    all_providers = set()
+    sessions_list = []
+
+    for session_id, load in session_loads.items():
+        total_requests += load.total_requests
+        all_providers.update(load.providers.keys())
+
+        state = tracker._sessions.get(session_id)
+        last_activity_seconds = 0.0
+        if state:
+            last_activity_seconds = now - state.last_request_time
+
+        req_per_min = 0.0
+        if state and state.requests_in_window > 0:
+            req_per_min = (state.requests_in_window / tracker._window_seconds) * 60
+
+        sessions_list.append(
+            {
+                "session_id": session_id,
+                "total_requests": load.total_requests,
+                "providers": list(load.providers.keys()),
+                "last_activity_seconds": last_activity_seconds,
+                "last_activity_display": _format_time(last_activity_seconds),
+                "requests_per_minute": int(req_per_min),
+            }
+        )
+
+    providers_list = []
+    for provider_id, load in provider_loads.items():
+        remaining = 0
+        if provider_id in blocked:
+            remaining = 30  # placeholder, real impl would check rate limiter
+        status = "Rate Limited" if not load.is_healthy else "Healthy"
+        if not load.is_healthy and remaining > 0:
+            status += f" ({remaining}s remaining)"
+
+        providers_list.append(
+            {
+                "provider_id": provider_id,
+                "active_requests": load.active_requests,
+                "sessions_count": load.session_count,
+                "requests_per_minute": int(load.requests_per_minute),
+                "is_healthy": load.is_healthy,
+                "status": status,
+            }
+        )
+
+    return {
+        "summary": {
+            "active_sessions": len(session_loads),
+            "total_requests": total_requests,
+            "providers": len(all_providers),
+        },
+        "sessions": sessions_list,
+        "providers": providers_list,
+    }
+
+
+@router.get("/admin", response_class=HTMLResponse)
+async def admin_dashboard(
+    request: Request,
+    _auth=Depends(require_api_key),
+):
+    """Admin dashboard HTML page."""
+    data = _get_admin_data()
+    return templates.TemplateResponse("admin.html", {"request": request, **data})
+
+
+@router.get("/api/admin/sessions")
+async def admin_sessions_json(
+    _auth=Depends(require_api_key),
+):
+    """JSON API for session data (for external tools)."""
+    return _get_admin_data()

api/app.py

@@ -15,6 +15,7 @@ from config.logging_config import configure_logging
 from config.settings import get_settings
 from providers.exceptions import ProviderError
 
+from .admin import router as admin_router
 from .routes import router
 from .runtime import AppRuntime, startup_failure_message
 from .validation_log import summarize_request_validation_body
@@ -96,6 +97,7 @@ def create_app(*, lifespan_enabled: bool = True) -> FastAPI:
 
     # Register routes
     app.include_router(router)
+    app.include_router(admin_router)
 
     # Exception handlers
     @app.exception_handler(RequestValidationError)

templates/admin.html

@@ -0,0 +1,138 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <meta http-equiv="refresh" content="10">
+    <title>Claude Code Proxy - Admin Dashboard</title>
+    <link href="https://cdn.jsdelivr.net/npm/bootstrap@5.3.0/dist/css/bootstrap.min.css" rel="stylesheet">
+    <style>
+        body { background-color: #f8f9fa; }
+        .dashboard-header { background: linear-gradient(135deg, #667eea 0%, #764ba2 100%); color: white; padding: 2rem 0; margin-bottom: 2rem; }
+        .stat-card { border-radius: 10px; box-shadow: 0 4px 6px rgba(0,0,0,0.1); }
+        .table-container { background: white; border-radius: 10px; box-shadow: 0 2px 4px rgba(0,0,0,0.05); padding: 1.5rem; margin-bottom: 2rem; }
+        .section-title { color: #495057; font-weight: 600; margin-bottom: 1rem; border-bottom: 2px solid #dee2e6; padding-bottom: 0.5rem; }
+        .status-healthy { color: #198754; font-weight: 500; }
+        .status-limited { color: #dc3545; font-weight: 500; }
+        .session-id { font-family: monospace; font-size: 0.9em; }
+    </style>
+</head>
+<body>
+    <div class="dashboard-header">
+        <div class="container">
+            <h1 class="mb-0">Claude Code Proxy - Admin Dashboard</h1>
+            <p class="mb-0 mt-2 opacity-75">Session Monitoring & Provider Load</p>
+        </div>
+    </div>
+
+    <div class="container">
+        <!-- Summary Stats -->
+        <div class="row mb-4">
+            <div class="col-md-4">
+                <div class="card stat-card bg-primary text-white">
+                    <div class="card-body">
+                        <h5 class="card-title">Active Sessions</h5>
+                        <h2 class="mb-0">{{ summary.active_sessions }}</h2>
+                    </div>
+                </div>
+            </div>
+            <div class="col-md-4">
+                <div class="card stat-card bg-success text-white">
+                    <div class="card-body">
+                        <h5 class="card-title">Total Requests</h5>
+                        <h2 class="mb-0">{{ summary.total_requests }}</h2>
+                    </div>
+                </div>
+            </div>
+            <div class="col-md-4">
+                <div class="card stat-card bg-info text-white">
+                    <div class="card-body">
+                        <h5 class="card-title">Providers</h5>
+                        <h2 class="mb-0">{{ summary.providers }}</h2>
+                    </div>
+                </div>
+            </div>
+        </div>
+
+        <!-- Sessions Table -->
+        <div class="table-container">
+            <h3 class="section-title">Sessions</h3>
+            {% if sessions %}
+            <div class="table-responsive">
+                <table class="table table-hover">
+                    <thead class="table-light">
+                        <tr>
+                            <th>Session ID</th>
+                            <th>Requests</th>
+                            <th>Providers</th>
+                            <th>Last Active</th>
+                            <th>Req/Min</th>
+                        </tr>
+                    </thead>
+                    <tbody>
+                        {% for session in sessions %}
+                        <tr>
+                            <td class="session-id" title="{{ session.session_id }}">{{ session.session_id[:12] }}...</td>
+                            <td>{{ session.total_requests }}</td>
+                            <td>
+                                {% for provider in session.providers %}
+                                <span class="badge bg-secondary">{{ provider }}</span>
+                                {% endfor %}
+                            </td>
+                            <td>{{ session.last_activity_display }}</td>
+                            <td>{{ session.requests_per_minute }}</td>
+                        </tr>
+                        {% endfor %}
+                    </tbody>
+                </table>
+            </div>
+            {% else %}
+            <p class="text-muted">No active sessions</p>
+            {% endif %}
+        </div>
+
+        <!-- Provider Load Table -->
+        <div class="table-container">
+            <h3 class="section-title">Provider Load</h3>
+            {% if providers %}
+            <div class="table-responsive">
+                <table class="table table-hover">
+                    <thead class="table-light">
+                        <tr>
+                            <th>Provider</th>
+                            <th>Active</th>
+                            <th>Sessions</th>
+                            <th>Req/Min</th>
+                            <th>Status</th>
+                        </tr>
+                    </thead>
+                    <tbody>
+                        {% for provider in providers %}
+                        <tr>
+                            <td class="session-id">{{ provider.provider_id }}</td>
+                            <td>{{ provider.active_requests }}</td>
+                            <td>{{ provider.sessions_count }}</td>
+                            <td>{{ provider.requests_per_minute }}</td>
+                            <td>
+                                {% if provider.is_healthy %}
+                                <span class="status-healthy">✓ {{ provider.status }}</span>
+                                {% else %}
+                                <span class="status-limited">⚠ {{ provider.status }}</span>
+                                {% endif %}
+                            </td>
+                        </tr>
+                        {% endfor %}
+                    </tbody>
+                </table>
+            </div>
+            {% else %}
+            <p class="text-muted">No provider data</p>
+            {% endif %}
+        </div>
+
+        <footer class="text-center text-muted py-3">
+            <small>Auto-refreshes every 10 seconds • <a href="/api/admin/sessions">JSON API</a></small>
+        </footer>
+    </div>
+</body>
+</html>