echo6-docs/runbooks/recon-service-integration.md

RECON Dashboard Service Integration

Add a management UI for a remote service to a Flask/FastAPI dashboard. The pattern: SSH key trust between the dashboard host and the target, scoped sudoers for specific commands, a REST API layer (GET /api/{service}/status + POST /api/{service}/{action}), and a frontend panel with status indicator, action buttons, and live feedback.

Use this when you have a service running on a remote LXC/VM that needs a web management interface — start/stop/restart, status checks, log tailing, or config hot-reload — without SSH-ing into the box manually.

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Prerequisites

• A running Flask or FastAPI dashboard (e.g., RECON on VM 131, WATCHTOWER on Contabo)
• The target service running on a reachable host (LXC, VM, or bare metal)
• SSH access from the dashboard host to the target host
• The dashboard runs as a known user (e.g., zvx, recon, watchtower)

---

Inputs

Prompt the user for all of these before executing:

DASHBOARD_HOST=         # Host running the dashboard (e.g., "192.168.1.130", "CT 130")
DASHBOARD_USER=         # User the dashboard runs as (e.g., "zvx")
DASHBOARD_APP_PATH=     # Path to the dashboard app (e.g., "/opt/recon/lib/api.py")
DASHBOARD_STATIC_PATH=  # Path to frontend files (e.g., "/opt/recon/lib/static/")
TARGET_HOST=            # Host running the service to manage (e.g., "192.168.1.170")
TARGET_USER=            # User to SSH as on the target (e.g., "zvx")
SERVICE_NAME=           # systemd service name (e.g., "peertube", "pt-downloader")
SERVICE_DISPLAY_NAME=   # Human-readable name for the UI (e.g., "PeerTube", "Downloader")
SERVICE_SLUG=           # URL-safe slug (e.g., "peertube", "downloader")
ALLOWED_ACTIONS=        # Comma-separated actions (e.g., "start,stop,restart,status,logs")

---

Step 1: Set Up SSH Key Trust

The dashboard host must be able to SSH to the target without a password prompt.

Generate key (if not already present)

ssh $DASHBOARD_HOST "test -f /home/$DASHBOARD_USER/.ssh/id_ed25519 || \
    ssh-keygen -t ed25519 -N '' -f /home/$DASHBOARD_USER/.ssh/id_ed25519"

Copy public key to target

# Get the public key
PUBKEY=$(ssh $DASHBOARD_HOST "cat /home/$DASHBOARD_USER/.ssh/id_ed25519.pub")

# Add to target's authorized_keys
ssh $TARGET_HOST "mkdir -p /home/$TARGET_USER/.ssh && \
    echo '$PUBKEY' >> /home/$TARGET_USER/.ssh/authorized_keys && \
    chmod 700 /home/$TARGET_USER/.ssh && \
    chmod 600 /home/$TARGET_USER/.ssh/authorized_keys && \
    chown -R $TARGET_USER:$TARGET_USER /home/$TARGET_USER/.ssh"

Gate

ssh $DASHBOARD_HOST "ssh -o BatchMode=yes -o ConnectTimeout=5 $TARGET_USER@$TARGET_HOST 'hostname'"

Must return the target hostname without prompting for a password. If it fails:

• "Permission denied (publickey)" → key not in authorized_keys, or wrong user
• "Host key verification failed" → add -o StrictHostKeyChecking=accept-new for first connection
• Timeout → network issue, firewall, or wrong IP

---

Step 2: Configure Scoped Sudoers on Target

Grant the target user passwordless sudo for only the specific commands the dashboard needs. Never use NOPASSWD: ALL for service integrations.

ssh root@$TARGET_HOST "cat > /etc/sudoers.d/${SERVICE_SLUG}-mgmt << 'SUDOERS'
# Allow $TARGET_USER to manage $SERVICE_NAME via dashboard
$TARGET_USER ALL=(ALL) NOPASSWD: /usr/bin/systemctl start $SERVICE_NAME
$TARGET_USER ALL=(ALL) NOPASSWD: /usr/bin/systemctl stop $SERVICE_NAME
$TARGET_USER ALL=(ALL) NOPASSWD: /usr/bin/systemctl restart $SERVICE_NAME
$TARGET_USER ALL=(ALL) NOPASSWD: /usr/bin/systemctl status $SERVICE_NAME
$TARGET_USER ALL=(ALL) NOPASSWD: /usr/bin/journalctl -u $SERVICE_NAME *
SUDOERS
chmod 440 /etc/sudoers.d/${SERVICE_SLUG}-mgmt"

Gate

ssh $DASHBOARD_HOST "ssh $TARGET_USER@$TARGET_HOST 'sudo systemctl status $SERVICE_NAME'"

Must return service status without a password prompt. If "sudo: a password is required", the sudoers file has a syntax error or isn't being loaded — check visudo -cf /etc/sudoers.d/${SERVICE_SLUG}-mgmt.

---

Step 3: Add API Endpoints

Add REST endpoints to the dashboard app for status checks and actions.

Flask pattern

import subprocess
import shlex

SERVICE_INTEGRATIONS = {
    '$SERVICE_SLUG': {
        'display_name': '$SERVICE_DISPLAY_NAME',
        'target_host': '$TARGET_USER@$TARGET_HOST',
        'service_name': '$SERVICE_NAME',
        'allowed_actions': ['start', 'stop', 'restart', 'status', 'logs'],
    },
}

def ssh_cmd(host: str, cmd: str, timeout: int = 10) -> dict:
    """Execute a command on a remote host via SSH."""
    full_cmd = f"ssh -o BatchMode=yes -o ConnectTimeout=5 {host} {shlex.quote(cmd)}"
    try:
        result = subprocess.run(
            full_cmd, shell=True, capture_output=True, text=True, timeout=timeout
        )
        return {
            'success': result.returncode == 0,
            'stdout': result.stdout.strip(),
            'stderr': result.stderr.strip(),
            'exit_code': result.returncode,
        }
    except subprocess.TimeoutExpired:
        return {'success': False, 'stdout': '', 'stderr': 'SSH command timed out', 'exit_code': -1}


@app.route('/api/services/<slug>/status')
def api_service_status(slug):
    svc = SERVICE_INTEGRATIONS.get(slug)
    if not svc:
        return jsonify({'error': 'Unknown service'}), 404

    result = ssh_cmd(svc['target_host'], f"sudo systemctl status {svc['service_name']}")

    # Parse systemctl status output
    active = 'active (running)' in result.get('stdout', '')
    return jsonify({
        'service': svc['display_name'],
        'active': active,
        'raw': result['stdout'],
    })


@app.route('/api/services/<slug>/<action>', methods=['POST'])
def api_service_action(slug, action):
    svc = SERVICE_INTEGRATIONS.get(slug)
    if not svc:
        return jsonify({'error': 'Unknown service'}), 404

    if action not in svc['allowed_actions']:
        return jsonify({'error': f'Action {action} not allowed'}), 403

    if action == 'logs':
        result = ssh_cmd(
            svc['target_host'],
            f"sudo journalctl -u {svc['service_name']} -n 50 --no-pager",
            timeout=15,
        )
    elif action in ('start', 'stop', 'restart'):
        result = ssh_cmd(svc['target_host'], f"sudo systemctl {action} {svc['service_name']}")
    elif action == 'status':
        result = ssh_cmd(svc['target_host'], f"sudo systemctl status {svc['service_name']}")
    else:
        return jsonify({'error': 'Unknown action'}), 400

    return jsonify(result)

FastAPI pattern

Same logic, different decorators:

@app.get('/api/services/{slug}/status')
async def api_service_status(slug: str):
    # Same implementation, wrapped in run_in_executor for async

@app.post('/api/services/{slug}/{action}')
async def api_service_action(slug: str, action: str):
    # Same implementation

Gate

Restart the dashboard and test:

curl -s http://$DASHBOARD_HOST:8420/api/services/$SERVICE_SLUG/status | python3 -m json.tool

Must return JSON with active: true/false and service details.

curl -s -X POST http://$DASHBOARD_HOST:8420/api/services/$SERVICE_SLUG/restart | python3 -m json.tool

Must return success: true.

---

Step 4: Add Frontend Panel

Add a service management panel to the dashboard UI. This goes in the appropriate tab (e.g., Upload, Dashboard, or a new Services tab).

<!-- Service Management Panel: $SERVICE_DISPLAY_NAME -->
<div class="service-panel" id="panel-$SERVICE_SLUG">
    <h3>$SERVICE_DISPLAY_NAME</h3>

    <!-- Status indicator -->
    <div class="status-row">
        <span class="status-dot" id="status-$SERVICE_SLUG"></span>
        <span id="status-text-$SERVICE_SLUG">Checking...</span>
        <button onclick="refreshStatus('$SERVICE_SLUG')" class="btn-sm">Refresh</button>
    </div>

    <!-- Action buttons -->
    <div class="action-buttons">
        <button onclick="serviceAction('$SERVICE_SLUG', 'restart')" class="btn btn-warning">Restart</button>
        <button onclick="serviceAction('$SERVICE_SLUG', 'stop')" class="btn btn-danger">Stop</button>
        <button onclick="serviceAction('$SERVICE_SLUG', 'start')" class="btn btn-success">Start</button>
        <button onclick="serviceAction('$SERVICE_SLUG', 'logs')" class="btn btn-info">View Logs</button>
    </div>

    <!-- Feedback area -->
    <pre id="feedback-$SERVICE_SLUG" class="feedback-box" style="display:none;"></pre>
</div>

// Service management JS
async function refreshStatus(slug) {
    const dot = document.getElementById(`status-${slug}`);
    const text = document.getElementById(`status-text-${slug}`);

    try {
        const resp = await fetch(`/api/services/${slug}/status`);
        const data = await resp.json();
        dot.className = data.active ? 'status-dot active' : 'status-dot inactive';
        text.textContent = data.active ? 'Running' : 'Stopped';
    } catch (e) {
        dot.className = 'status-dot error';
        text.textContent = 'Unreachable';
    }
}

async function serviceAction(slug, action) {
    const feedback = document.getElementById(`feedback-${slug}`);
    feedback.style.display = 'block';
    feedback.textContent = `Executing ${action}...`;

    try {
        const resp = await fetch(`/api/services/${slug}/${action}`, { method: 'POST' });
        const data = await resp.json();
        feedback.textContent = data.stdout || data.stderr || (data.success ? 'Done' : 'Failed');

        // Refresh status after action
        if (['start', 'stop', 'restart'].includes(action)) {
            setTimeout(() => refreshStatus(slug), 2000);
        }
    } catch (e) {
        feedback.textContent = `Error: ${e.message}`;
    }
}

// Auto-refresh status every 30 seconds
setInterval(() => {
    document.querySelectorAll('.service-panel').forEach(panel => {
        const slug = panel.id.replace('panel-', '');
        refreshStatus(slug);
    });
}, 30000);

// Initial load
document.addEventListener('DOMContentLoaded', () => {
    document.querySelectorAll('.service-panel').forEach(panel => {
        const slug = panel.id.replace('panel-', '');
        refreshStatus(slug);
    });
});

.status-dot {
    display: inline-block;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    margin-right: 8px;
}
.status-dot.active { background: #22c55e; }
.status-dot.inactive { background: #ef4444; }
.status-dot.error { background: #f59e0b; }
.feedback-box {
    background: #1e1e2e;
    color: #cdd6f4;
    padding: 12px;
    border-radius: 4px;
    max-height: 300px;
    overflow-y: auto;
    font-size: 12px;
    margin-top: 8px;
}

---

Step 5: Verify End-to-End

1. Load the dashboard in a browser: http://$DASHBOARD_HOST:8420/
2. Check status indicator: should show green dot + "Running" (or red + "Stopped")
3. Click Restart: feedback box should show systemctl output, status should flip briefly then return to Running
4. Click View Logs: should show last 50 journal lines
5. Click Stop: status should change to Stopped (red)
6. Click Start: status should change to Running (green)

---

Adding More Services

To integrate a second service, repeat Steps 1-4 with new inputs. The SERVICE_INTEGRATIONS dict supports multiple entries:

SERVICE_INTEGRATIONS = {
    'peertube': { ... },
    'downloader': {
        'display_name': 'Bulk Downloader',
        'target_host': 'zvx@192.168.1.170',
        'service_name': 'pt-downloader',
        'allowed_actions': ['start', 'stop', 'restart', 'status', 'logs'],
    },
    'transcoder': {
        'display_name': 'H.265 Transcoder',
        'target_host': 'zvx@192.168.1.150',
        'service_name': 'pt-transcoder',
        'allowed_actions': ['start', 'stop', 'restart', 'status', 'logs'],
    },
}

Each service gets its own panel in the UI, its own sudoers file on the target, and its own API routes (all handled by the generic /<slug>/<action> pattern).

---

Security Considerations

• Scoped sudoers: Only allow the specific systemctl and journalctl commands needed. Never NOPASSWD: ALL.
• SSH BatchMode: BatchMode=yes ensures SSH never falls back to interactive password prompt. If key auth fails, the command fails immediately.
• Action allowlist: The allowed_actions list prevents the API from executing arbitrary commands. Only listed actions are accepted.
• No shell injection: Use shlex.quote() on any user-provided or variable input before passing to subprocess.run(shell=True). Or use subprocess.run(cmd_list) with a list to avoid shell entirely.
• Timeout on SSH: Always set -o ConnectTimeout and subprocess.run(timeout=) to prevent the dashboard from hanging on network issues.

---

Troubleshooting

Status shows "Unreachable"

SSH from the dashboard host to the target is failing. Test manually:

ssh -o BatchMode=yes -o ConnectTimeout=5 $TARGET_USER@$TARGET_HOST 'hostname'

Common causes: SSH key not deployed, wrong user, firewall, target host down.

"sudo: a password is required"

The sudoers file isn't working. Check:

ssh root@$TARGET_HOST "visudo -cf /etc/sudoers.d/${SERVICE_SLUG}-mgmt"

Must say "parsed OK". Also verify the username in the sudoers file matches $TARGET_USER.

Actions work via curl but not from the browser

CORS issue. Add CORS headers to the API:

# Flask
from flask_cors import CORS
CORS(app)

# Or manually:
@app.after_request
def add_cors(response):
    response.headers['Access-Control-Allow-Origin'] = '*'
    response.headers['Access-Control-Allow-Methods'] = 'GET, POST'
    return response

Dashboard hangs when target host is down

The SSH timeout isn't working, or it's set too high. Ensure both -o ConnectTimeout=5 (SSH) and timeout=10 (subprocess) are set. The subprocess timeout is the hard limit.

Log output is truncated

The -n 50 flag limits journalctl output. Increase it, or add a lines query parameter:

lines = request.args.get('lines', 50, type=int)
lines = min(lines, 500)  # Cap to prevent abuse

---

Usage Examples

RECON managing pipeline services (CT 130 dashboard → CT 110 PeerTube)

DASHBOARD_HOST=192.168.1.130 (VM 131, data node)
DASHBOARD_USER=zvx
TARGET_HOST=192.168.1.170 (CT 110, media node)
SERVICE_NAME=peertube
SERVICE_SLUG=peertube

Sudoers on CT 110:
  zvx ALL=(ALL) NOPASSWD: /usr/bin/systemctl start peertube
  zvx ALL=(ALL) NOPASSWD: /usr/bin/systemctl stop peertube
  zvx ALL=(ALL) NOPASSWD: /usr/bin/systemctl restart peertube
  zvx ALL=(ALL) NOPASSWD: /usr/bin/systemctl status peertube
  zvx ALL=(ALL) NOPASSWD: /usr/bin/journalctl -u peertube *

API endpoints:
  GET  /api/services/peertube/status   → returns active/inactive + raw systemctl output
  POST /api/services/peertube/restart  → restarts PeerTube, returns success/failure
  POST /api/services/peertube/logs     → returns last 50 journal lines

Dashboard panel: green/red dot + Restart/Stop/Start/Logs buttons + feedback box

WATCHTOWER monitoring remote services (Contabo → multiple hosts)

DASHBOARD_HOST=5.189.158.149 (Contabo)
DASHBOARD_USER=root

Services managed:
  - peertube (CT 110): start/stop/restart/status/logs
  - pt-downloader (CT 110): start/stop/restart/status/logs
  - pt-importer (CT 110): start/stop/restart/status/logs
  - pt-transcoder (cortex): start/stop/restart/status/logs
  - recon (VM 131): start/stop/restart/status/logs

Each service has its own sudoers file on its target host,
its own entry in SERVICE_INTEGRATIONS, and its own UI panel.

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Last updated: 2026-04-19 — Updated CT 130 references to VM 131