Merge pull request 'feat: push-based monitoring with remote agent' (#35) from feat/push-monitoring-agent into master

Reviewed-on: #35

bin/agent.sh

@@ -0,0 +1,83 @@
+#!/bin/bash
+# ServerManager Monitoring Agent
+# This script runs as a systemd service on monitored servers.
+set -e
+
+CONFIG_FILE="/etc/servermanager/agent.conf"
+
+load_config() {
+    if [ -f "$CONFIG_FILE" ]; then
+        source "$CONFIG_FILE"
+    fi
+    SERVER_URL="${SERVER_URL:-}"
+    AGENT_KEY="${AGENT_KEY:-}"
+    INTERVAL="${INTERVAL:-60}"
+}
+
+collect_metrics() {
+    CPU=$(top -bn1 2>/dev/null | grep 'Cpu(s)' | awk '{print $2}' | cut -d'%' -f1)
+    [ -z "$CPU" ] && CPU=0
+
+    RAM=$(free 2>/dev/null | grep Mem | awk '{printf "%.1f", $3/$2 * 100}')
+    [ -z "$RAM" ] && RAM=0
+
+    DISK=$(df / 2>/dev/null | tail -1 | awk '{print $5}' | sed 's/%//')
+    [ -z "$DISK" ] && DISK=0
+
+    LOAD=$(cat /proc/loadavg 2>/dev/null | awk '{print $1}')
+    [ -z "$LOAD" ] && LOAD=0
+
+    UPTIME=$(uptime -p 2>/dev/null | sed 's/^up //')
+    [ -z "$UPTIME" ] && UPTIME=""
+}
+
+push_metrics() {
+    local payload
+    payload=$(cat <<EOF
+{
+    "agent_key": "$AGENT_KEY",
+    "cpu": $CPU,
+    "ram": $RAM,
+    "disk": $DISK,
+    "load": $LOAD,
+    "uptime": "$UPTIME"
+}
+EOF
+)
+    curl -s -X POST "$SERVER_URL/api/metrics/push" \
+        -H "Content-Type: application/json" \
+        -d "$payload" \
+        --connect-timeout 10 \
+        --max-time 30 \
+        -o /dev/null -w "%{http_code}" 2>/dev/null || echo "000"
+}
+
+main() {
+    load_config
+
+    if [ -z "$SERVER_URL" ] || [ -z "$AGENT_KEY" ]; then
+        echo "ERROR: SERVER_URL and AGENT_KEY must be set in $CONFIG_FILE"
+        exit 1
+    fi
+
+    echo "ServerManager Agent started"
+    echo "Server: $SERVER_URL"
+    echo "Interval: ${INTERVAL}s"
+
+    sleep 5
+
+    while true; do
+        collect_metrics
+        http_code=$(push_metrics)
+
+        if [ "$http_code" = "200" ]; then
+            echo "[$(date)] Metrics pushed successfully"
+        else
+            echo "[$(date)] Failed to push metrics (HTTP $http_code)"
+        fi
+
+        sleep "$INTERVAL"
+    done
+}
+
+main

database/migrations/006_agent_tokens.sql

@@ -0,0 +1,9 @@
+ALTER TABLE servers
+  ADD COLUMN agent_key VARCHAR(64) DEFAULT NULL AFTER ssh_key,
+  ADD COLUMN agent_installed TINYINT(1) NOT NULL DEFAULT 0 AFTER agent_key,
+  ADD COLUMN agent_install_path VARCHAR(255) DEFAULT NULL AFTER agent_installed,
+  ADD COLUMN agent_last_seen_at DATETIME DEFAULT NULL AFTER agent_install_path;
+
+CREATE UNIQUE INDEX idx_servers_agent_key ON servers(agent_key);
+
+UPDATE servers SET agent_key = LOWER(HEX(RANDOM_BYTES(32))) WHERE agent_key IS NULL;

install/agent-install.sh

@@ -0,0 +1,136 @@
+#!/bin/bash
+# ServerManager Agent Installer
+# Usage: bash agent-install.sh <SERVER_URL> <AGENT_KEY> [INTERVAL]
+set -e
+
+SERVER_URL="${1:-}"
+AGENT_KEY="${2:-}"
+INTERVAL="${3:-60}"
+
+if [ -z "$SERVER_URL" ] || [ -z "$AGENT_KEY" ]; then
+    echo "Usage: bash agent-install.sh <SERVER_URL> <AGENT_KEY> [INTERVAL]"
+    exit 1
+fi
+
+AGENT_BIN="/usr/local/bin/servermanager-agent"
+CONFIG_DIR="/etc/servermanager"
+CONFIG_FILE="$CONFIG_DIR/agent.conf"
+SERVICE_FILE="/etc/systemd/system/servermanager-agent.service"
+
+echo "[1/5] Creating config directory..."
+mkdir -p "$CONFIG_DIR"
+
+echo "[2/5] Installing agent binary..."
+cat > "$AGENT_BIN" << 'AGENTSCRIPT'
+#!/bin/bash
+set -e
+CONFIG_FILE="/etc/servermanager/agent.conf"
+
+load_config() {
+    if [ -f "$CONFIG_FILE" ]; then
+        source "$CONFIG_FILE"
+    fi
+    SERVER_URL="${SERVER_URL:-}"
+    AGENT_KEY="${AGENT_KEY:-}"
+    INTERVAL="${INTERVAL:-60}"
+}
+
+collect_metrics() {
+    CPU=$(top -bn1 2>/dev/null | grep 'Cpu(s)' | awk '{print $2}' | cut -d'%' -f1)
+    [ -z "$CPU" ] && CPU=0
+    RAM=$(free 2>/dev/null | grep Mem | awk '{printf "%.1f", $3/$2 * 100}')
+    [ -z "$RAM" ] && RAM=0
+    DISK=$(df / 2>/dev/null | tail -1 | awk '{print $5}' | sed 's/%//')
+    [ -z "$DISK" ] && DISK=0
+    LOAD=$(cat /proc/loadavg 2>/dev/null | awk '{print $1}')
+    [ -z "$LOAD" ] && LOAD=0
+    UPTIME=$(uptime -p 2>/dev/null | sed 's/^up //')
+    [ -z "$UPTIME" ] && UPTIME=""
+}
+
+push_metrics() {
+    local payload
+    payload=$(cat <<EOF
+{
+    "agent_key": "$AGENT_KEY",
+    "cpu": $CPU,
+    "ram": $RAM,
+    "disk": $DISK,
+    "load": $LOAD,
+    "uptime": "$UPTIME"
+}
+EOF
+)
+    curl -s -X POST "$SERVER_URL/api/metrics/push" \
+        -H "Content-Type: application/json" \
+        -d "$payload" \
+        --connect-timeout 10 --max-time 30 \
+        -o /dev/null -w "%{http_code}" 2>/dev/null || echo "000"
+}
+
+main() {
+    load_config
+    if [ -z "$SERVER_URL" ] || [ -z "$AGENT_KEY" ]; then
+        echo "ERROR: SERVER_URL and AGENT_KEY must be set in $CONFIG_FILE"
+        exit 1
+    fi
+    echo "ServerManager Agent started (interval: ${INTERVAL}s)"
+    sleep 5
+    while true; do
+        collect_metrics
+        http_code=$(push_metrics)
+        if [ "$http_code" = "200" ]; then
+            echo "[$(date)] Metrics pushed successfully"
+        else
+            echo "[$(date)] Failed to push metrics (HTTP $http_code)"
+        fi
+        sleep "$INTERVAL"
+    done
+}
+main
+AGENTSCRIPT
+chmod +x "$AGENT_BIN"
+
+echo "[3/5] Writing config..."
+cat > "$CONFIG_FILE" << EOF
+SERVER_URL="$SERVER_URL"
+AGENT_KEY="$AGENT_KEY"
+INTERVAL=$INTERVAL
+EOF
+chmod 600 "$CONFIG_FILE"
+
+echo "[4/5] Installing systemd service..."
+cat > "$SERVICE_FILE" << 'UNIT'
+[Unit]
+Description=ServerManager Monitoring Agent
+Documentation=https://github.com/servermanager
+After=network-online.target
+Wants=network-online.target
+
+[Service]
+Type=simple
+ExecStart=/usr/local/bin/servermanager-agent
+Restart=always
+RestartSec=10
+StartLimitIntervalSec=60
+StartLimitBurst=5
+NoNewPrivileges=yes
+ProtectSystem=full
+ProtectHome=yes
+PrivateDevices=yes
+PrivateTmp=yes
+
+[Install]
+WantedBy=multi-user.target
+UNIT
+
+echo "[5/5] Enabling and starting service..."
+systemctl daemon-reload
+systemctl enable servermanager-agent
+systemctl restart servermanager-agent
+
+echo ""
+echo "ServerManager Agent installed successfully!"
+echo "  Binary: $AGENT_BIN"
+echo "  Config: $CONFIG_FILE"
+echo "  Service: $SERVICE_FILE"

install/agent-uninstall.sh

@@ -0,0 +1,22 @@
+#!/bin/bash
+# ServerManager Agent Uninstaller
+set -e
+
+AGENT_BIN="/usr/local/bin/servermanager-agent"
+CONFIG_DIR="/etc/servermanager"
+SERVICE_FILE="/etc/systemd/system/servermanager-agent.service"
+
+echo "[1/3] Stopping and disabling service..."
+systemctl stop servermanager-agent 2>/dev/null || true
+systemctl disable servermanager-agent 2>/dev/null || true
+systemctl daemon-reload
+
+echo "[2/3] Removing files..."
+rm -f "$AGENT_BIN"
+rm -rf "$CONFIG_DIR"
+rm -f "$SERVICE_FILE"
+
+echo "[3/3] Reloading systemd..."
+systemctl daemon-reload
+
+echo "ServerManager Agent uninstalled successfully."

install/servermanager-agent.service

@@ -0,0 +1,21 @@
+[Unit]
+Description=ServerManager Monitoring Agent
+Documentation=https://github.com/servermanager
+After=network-online.target
+Wants=network-online.target
+
+[Service]
+Type=simple
+ExecStart=/usr/local/bin/servermanager-agent
+Restart=always
+RestartSec=10
+StartLimitIntervalSec=60
+StartLimitBurst=5
+NoNewPrivileges=yes
+ProtectSystem=full
+ProtectHome=yes
+PrivateDevices=yes
+PrivateTmp=yes
+
+[Install]
+WantedBy=multi-user.target

routes/web.php

@@ -122,3 +122,8 @@ $router->get('/api/users', [ApiController::class, 'users']);
 $router->get('/api/profile', [ApiController::class, 'profile']);
 $router->put('/api/profile', [ApiController::class, 'updateProfile']);
 $router->get('/api/refresh-metrics', [ApiController::class, 'refreshAllMetrics']);
+$router->post('/api/metrics/push', [ApiController::class, 'pushMetrics']);
+
+$router->post('/servers/:id/agent/install', [ServerController::class, 'agentInstall'], [AuthMiddleware::class, CSRFMiddleware::class]);
+$router->post('/servers/:id/agent/uninstall', [ServerController::class, 'agentUninstall'], [AuthMiddleware::class, CSRFMiddleware::class]);
+$router->post('/servers/:id/agent/regenerate-key', [ServerController::class, 'agentRegenerateKey'], [AuthMiddleware::class, CSRFMiddleware::class]);

src/Controllers/ApiController.php

@@ -114,6 +114,8 @@ class ApiController
         $monitoringService = new MonitoringService();
         $metrics = $monitoringService->getLatestMetrics($id);
 
+        unset($server['agent_key'], $server['ssh_password'], $server['ssh_key']);
+
         $this->view->json([
             'success' => true,
             'data' => [
@@ -296,6 +298,43 @@ class ApiController
         ]);
     }
 
+    public function pushMetrics(): void
+    {
+        $input = json_decode(file_get_contents('php://input'), true);
+
+        if (!$input || empty($input['agent_key'])) {
+            $this->view->json(['error' => 'agent_key is required'], 401);
+        }
+
+        $serverModel = new Server();
+        $server = $serverModel->findByAgentKey($input['agent_key']);
+
+        if (!$server || !$server['is_active']) {
+            $this->view->json(['error' => 'Invalid agent key'], 401);
+        }
+
+        $cpu = isset($input['cpu']) ? max(0, min(100, (float) $input['cpu'])) : 0;
+        $ram = isset($input['ram']) ? max(0, min(100, (float) $input['ram'])) : 0;
+        $disk = isset($input['disk']) ? max(0, min(100, (float) $input['disk'])) : 0;
+        $load = (float) ($input['load'] ?? 0);
+        $uptime = (string) ($input['uptime'] ?? '');
+
+        $monitoring = new MonitoringService();
+        $monitoring->saveMetrics([
+            'server_id' => (int) $server['id'],
+            'status' => 'online',
+            'cpu_usage' => $cpu,
+            'ram_usage' => $ram,
+            'disk_usage' => $disk,
+            'load_average' => $load,
+            'uptime' => $uptime,
+        ]);
+
+        $serverModel->updateAgentLastSeen((int) $server['id']);
+
+        $this->view->json(['success' => true]);
+    }
+
     public function refreshAllMetrics(): void
     {
         $user = $this->authenticateRequest();

src/Controllers/ServerController.php

@@ -255,6 +255,40 @@ class ServerController
         ]);
     }
 
+    public function agentInstall(int $id): void
+    {
+        $server = $this->requireServerAccess($id, 'manager');
+
+        $agentService = new \ServerManager\Services\AgentService();
+        $result = $agentService->install($id);
+
+        $this->view->json($result);
+    }
+
+    public function agentUninstall(int $id): void
+    {
+        $server = $this->requireServerAccess($id, 'manager');
+
+        $agentService = new \ServerManager\Services\AgentService();
+        $result = $agentService->uninstall($id);
+
+        $this->view->json($result);
+    }
+
+    public function agentRegenerateKey(int $id): void
+    {
+        $this->requireServerAccess($id, 'manager');
+
+        $newKey = $this->serverModel->regenerateAgentKey($id);
+
+        $this->auditService->log('agent_key_regenerated', 'server', $id);
+
+        $this->view->json([
+            'success' => true,
+            'agent_key' => $newKey,
+        ]);
+    }
+
     public function testConnection(int $id): void
     {
         $server = $this->requireServerAccess($id, 'viewer');

src/Models/Server.php

@@ -122,6 +122,10 @@ class Server
             $data['ssh_key'] = null;
         }
 
+        if (empty($data['agent_key'])) {
+            $data['agent_key'] = $this->generateAgentKey();
+        }
+
         $data['created_at'] = date('Y-m-d H:i:s');
         $data['updated_at'] = date('Y-m-d H:i:s');
 
@@ -405,4 +409,47 @@ class Server
             [$userId]
         );
     }
+
+    public function findByAgentKey(string $key): ?array
+    {
+        $server = $this->db->fetch(
+            'SELECT * FROM servers WHERE agent_key = ? AND status = \'active\'',
+            [$key]
+        );
+        if ($server) {
+            $server = $this->encryption->decryptArray($server, $this->encryptedFields);
+        }
+        return $server;
+    }
+
+    public function generateAgentKey(): string
+    {
+        return bin2hex(random_bytes(32));
+    }
+
+    public function regenerateAgentKey(int $id): string
+    {
+        $key = $this->generateAgentKey();
+        $this->db->update('servers', [
+            'agent_key' => $key,
+            'updated_at' => date('Y-m-d H:i:s'),
+        ], 'id = ?', [$id]);
+        return $key;
+    }
+
+    public function updateAgentLastSeen(int $id): bool
+    {
+        return $this->db->update('servers', [
+            'agent_last_seen_at' => date('Y-m-d H:i:s'),
+        ], 'id = ?', [$id]) > 0;
+    }
+
+    public function setAgentInstalled(int $id, bool $installed, ?string $path = null): bool
+    {
+        return $this->db->update('servers', [
+            'agent_installed' => $installed ? 1 : 0,
+            'agent_install_path' => $path,
+            'updated_at' => date('Y-m-d H:i:s'),
+        ], 'id = ?', [$id]) > 0;
+    }
 }

src/Services/AgentService.php

@@ -0,0 +1,159 @@
+<?php
+
+declare(strict_types=1);
+
+namespace ServerManager\Services;
+
+use ServerManager\Core\App;
+use ServerManager\Core\Database;
+use ServerManager\Core\Logger;
+
+class AgentService
+{
+    private Database $db;
+    private Logger $logger;
+    private string $basePath;
+
+    public function __construct()
+    {
+        $this->db = Database::getInstance();
+        $this->logger = Logger::getInstance();
+        $this->basePath = dirname(__DIR__, 2);
+    }
+
+    public function install(int $serverId): array
+    {
+        $server = $this->db->fetch(
+            'SELECT * FROM servers WHERE id = ? AND status = \'active\' AND is_active = 1',
+            [$serverId]
+        );
+
+        if (!$server) {
+            return ['success' => false, 'error' => 'Server not found or inactive'];
+        }
+
+        $server = App::getEncryption()->decryptArray($server, ['ssh_password', 'ssh_key']);
+
+        $agentKey = $server['agent_key'];
+        $serverUrl = rtrim((App::getConfig()['app']['url'] ?? ''), '/');
+
+        if (empty($serverUrl)) {
+            $serverUrl = ($_SERVER['HTTPS'] ?? '' === 'on' ? 'https://' : 'http://') . ($_SERVER['HTTP_HOST'] ?? 'localhost');
+        }
+
+        $scriptPath = $this->basePath . '/install/agent-install.sh';
+
+        if (!file_exists($scriptPath)) {
+            return ['success' => false, 'error' => 'Agent install script not found'];
+        }
+
+        $script = file_get_contents($scriptPath);
+
+        $remoteCommand = sprintf(
+            'echo %s | base64 -d | bash -s -- %s %s 2>&1',
+            escapeshellarg(base64_encode($script)),
+            escapeshellarg($serverUrl),
+            escapeshellarg($agentKey)
+        );
+
+        try {
+            $ssh = new SSHService();
+            if (!$ssh->connect($server, true)) {
+                return ['success' => false, 'error' => 'SSH connection failed'];
+            }
+
+            $result = $ssh->exec($remoteCommand, 120);
+            $ssh->disconnect();
+
+            $output = trim($result['output']);
+            $exitStatus = $result['exit_status'] ?? -1;
+
+            if ($exitStatus !== 0) {
+                return [
+                    'success' => false,
+                    'error' => 'Agent installation failed on remote server',
+                    'output' => $output,
+                ];
+            }
+
+            $path = '/usr/local/bin/servermanager-agent';
+
+            $serverModel = new \ServerManager\Models\Server();
+            $serverModel->setAgentInstalled($serverId, true, $path);
+
+            $auditService = new AuditService();
+            $auditService->log('agent_installed', 'server', $serverId, [
+                'name' => $server['name'],
+                'path' => $path,
+            ]);
+
+            return ['success' => true, 'path' => $path, 'output' => $output];
+        } catch (\Throwable $e) {
+            $this->logger->error("Agent install failed for server {$serverId}: " . $e->getMessage());
+            return ['success' => false, 'error' => $e->getMessage()];
+        }
+    }
+
+    public function uninstall(int $serverId): array
+    {
+        $server = $this->db->fetch(
+            'SELECT * FROM servers WHERE id = ? AND status = \'active\' AND is_active = 1',
+            [$serverId]
+        );
+
+        if (!$server) {
+            return ['success' => false, 'error' => 'Server not found or inactive'];
+        }
+
+        $server = App::getEncryption()->decryptArray($server, ['ssh_password', 'ssh_key']);
+
+        $scriptPath = $this->basePath . '/install/agent-uninstall.sh';
+
+        if (!file_exists($scriptPath)) {
+            return ['success' => false, 'error' => 'Agent uninstall script not found'];
+        }
+
+        $script = file_get_contents($scriptPath);
+
+        $remoteCommand = sprintf(
+            'echo %s | base64 -d | bash 2>&1',
+            escapeshellarg(base64_encode($script))
+        );
+
+        try {
+            $ssh = new SSHService();
+            if (!$ssh->connect($server, true)) {
+                return ['success' => false, 'error' => 'SSH connection failed'];
+            }
+
+            $result = $ssh->exec($remoteCommand, 60);
+            $ssh->disconnect();
+
+            $output = trim($result['output']);
+            $exitStatus = $result['exit_status'] ?? -1;
+
+            $serverModel = new \ServerManager\Models\Server();
+            $serverModel->setAgentInstalled($serverId, false, null);
+
+            $auditService = new AuditService();
+            $auditService->log('agent_uninstalled', 'server', $serverId, [
+                'name' => $server['name'],
+            ]);
+
+            if ($exitStatus !== 0) {
+                return [
+                    'success' => false,
+                    'error' => 'Agent uninstallation may have failed on remote server',
+                    'output' => $output,
+                ];
+            }
+
+            return ['success' => true, 'output' => $output];
+        } catch (\Throwable $e) {
+            $this->logger->error("Agent uninstall failed for server {$serverId}: " . $e->getMessage());
+            $serverModel = new \ServerManager\Models\Server();
+            $serverModel->setAgentInstalled($serverId, false, null);
+            return ['success' => false, 'error' => $e->getMessage()];
+        }
+    }
+}

src/Services/MonitoringService.php

@@ -111,7 +111,7 @@ class MonitoringService
         return trim(str_replace('up ', '', $result['output']));
     }
 
-    private function saveMetrics(array $metrics): void
+    public function saveMetrics(array $metrics): void
     {
         $now = date('Y-m-d H:i:s');
 

views/servers/show.php

@@ -139,6 +139,58 @@ $canManage = $server_role === 'owner' || $server_role === 'manager';
             </dl>
         </div>
     </div>
+
+    <div class="dashboard-card">
+        <div class="card-header">
+            <h2><i class="fas fa-wifi"></i> Monitoring Agent</h2>
+        </div>
+        <div class="card-body">
+            <?php if (!empty($server['agent_key'])): ?>
+            <dl class="details-list">
+                <dt>Agent Key</dt>
+                <dd>
+                    <code id="agentKeyDisplay"><?= substr($server['agent_key'], 0, 12) ?>...<?= substr($server['agent_key'], -4) ?></code>
+                    <button class="btn btn-sm btn-secondary" onclick="copyAgentKey()" title="Copy full key">
+                        <i class="fas fa-copy"></i>
+                    </button>
+                    <input type="hidden" id="agentKeyFull" value="<?= htmlspecialchars($server['agent_key']) ?>">
+                </dd>
+                <dt>Status</dt>
+                <dd>
+                    <?php if ($server['agent_installed'] ?? false): ?>
+                        <span class="badge badge-success">Installed</span>
+                    <?php else: ?>
+                        <span class="badge badge-secondary">Not installed</span>
+                    <?php endif; ?>
+                </dd>
+                <?php if (!empty($server['agent_install_path'])): ?>
+                <dt>Install Path</dt>
+                <dd><code><?= htmlspecialchars($server['agent_install_path']) ?></code></dd>
+                <?php endif; ?>
+                <dt>Last Seen</dt>
+                <dd><?= $server['agent_last_seen_at'] ?? 'Never' ?></dd>
+            </dl>
+            <div class="form-actions" style="margin-top:1rem">
+                <?php if ($canManage): ?>
+                    <?php if ($server['agent_installed'] ?? false): ?>
+                        <button onclick="showAgentModal('uninstall')" class="btn btn-danger">
+                            <i class="fas fa-minus-circle"></i> Uninstall Agent
+                        </button>
+                    <?php else: ?>
+                        <button onclick="showAgentModal('install')" class="btn btn-primary">
+                            <i class="fas fa-plus-circle"></i> Install Agent
+                        </button>
+                    <?php endif; ?>
+                    <button onclick="regenerateAgentKey()" class="btn btn-secondary" title="Regenerate agent key">
+                        <i class="fas fa-key"></i> Regenerate Key
+                    </button>
+                <?php endif; ?>
+            </div>
+            <?php else: ?>
+            <p class="text-muted">No agent key configured.</p>
+            <?php endif; ?>
+        </div>
+    </div>
 </div>
 
 <div class="card">
@@ -195,6 +247,28 @@ $canManage = $server_role === 'owner' || $server_role === 'manager';
     </div>
 </div>
 
+<div id="agentConfirmModal" class="modal">
+    <div class="modal-dialog">
+        <div class="modal-header">
+            <h3 id="agentModalTitle">Install Monitoring Agent</h3>
+            <button type="button" class="modal-close" onclick="closeAgentModal()">&times;</button>
+        </div>
+        <div class="modal-body">
+            <p id="agentModalMessage">
+                This will install the monitoring agent on <strong><?= htmlspecialchars($server['name'] ?? '') ?></strong> via SSH.
+            </p>
+            <p class="text-muted">
+                The agent will run as a systemd service, collecting and sending metrics every 60 seconds.
+                It will automatically restart if the server reboots.
+            </p>
+        </div>
+        <div class="modal-footer">
+            <button id="agentModalConfirmBtn" class="btn btn-primary" onclick="confirmAgentAction()">Install</button>
+            <button class="btn btn-secondary" onclick="closeAgentModal()">Cancel</button>
+        </div>
+    </div>
+</div>
+
 <form id="csrfForm" style="display:none">
     <input type="hidden" name="_csrf_token" value="<?= $this->csrfToken() ?>">
 </form>
@@ -315,6 +389,107 @@ if (historicalData.length > 0) {
     initChart(historicalData);
 }
 
+let pendingAgentAction = null;
+
+function showAgentModal(action) {
+    pendingAgentAction = action;
+    const modal = document.getElementById('agentConfirmModal');
+    const title = document.getElementById('agentModalTitle');
+    const msg = document.getElementById('agentModalMessage');
+    const btn = document.getElementById('agentModalConfirmBtn');
+
+    if (action === 'install') {
+        title.textContent = 'Install Monitoring Agent';
+        msg.innerHTML = 'This will install the monitoring agent on <strong><?= htmlspecialchars($server['name'] ?? '') ?></strong> via SSH.';
+        btn.textContent = 'Install';
+        btn.className = 'btn btn-primary';
+    } else {
+        title.textContent = 'Uninstall Monitoring Agent';
+        msg.innerHTML = 'This will uninstall the monitoring agent from <strong><?= htmlspecialchars($server['name'] ?? '') ?></strong> via SSH. The service will be stopped and all agent files removed.';
+        btn.textContent = 'Uninstall';
+        btn.className = 'btn btn-danger';
+    }
+
+    modal.style.display = 'flex';
+    modal.onclick = function(e) {
+        if (e.target === modal) closeAgentModal();
+    };
+}
+
+function closeAgentModal() {
+    document.getElementById('agentConfirmModal').style.display = 'none';
+    pendingAgentAction = null;
+}
+
+function confirmAgentAction() {
+    if (!pendingAgentAction) return;
+
+    const action = pendingAgentAction;
+    const btn = document.getElementById('agentModalConfirmBtn');
+    btn.disabled = true;
+    btn.textContent = action === 'install' ? 'Installing...' : 'Uninstalling...';
+
+    closeAgentModal();
+
+    fetch('/servers/<?= $server['id'] ?>/agent/' + action, {
+        method: 'POST',
+        headers: {
+            'Content-Type': 'application/x-www-form-urlencoded',
+            'X-CSRF-Token': getCsrfToken(),
+        },
+        body: '_csrf_token=' + encodeURIComponent(getCsrfToken()),
+    })
+    .then(r => r.json())
+    .then(data => {
+        if (data.success) {
+            showToast('success', action === 'install' ? 'Agent installed successfully.' : 'Agent uninstalled successfully.');
+            setTimeout(() => location.reload(), 1500);
+        } else {
+            showToast('error', data.error || (action === 'install' ? 'Installation failed.' : 'Uninstallation failed.'));
+            if (data.output) console.log('Output:', data.output);
+        }
+    })
+    .catch(err => {
+        showToast('error', 'Request failed: ' + err.message);
+    })
+    .finally(() => {
+        btn.disabled = false;
+        btn.textContent = action === 'install' ? 'Install' : 'Uninstall';
+    });
+}
+
+function copyAgentKey() {
+    const key = document.getElementById('agentKeyFull').value;
+    navigator.clipboard.writeText(key).then(() => {
+        showToast('success', 'Agent key copied to clipboard.');
+    }).catch(() => {
+        showToast('error', 'Failed to copy agent key.');
+    });
+}
+
+function regenerateAgentKey() {
+    if (!confirm('Regenerate agent key? The current key will stop working immediately.')) return;
+
+    fetch('/servers/<?= $server['id'] ?>/agent/regenerate-key', {
+        method: 'POST',
+        headers: {
+            'Content-Type': 'application/x-www-form-urlencoded',
+            'X-CSRF-Token': getCsrfToken(),
+        },
+        body: '_csrf_token=' + encodeURIComponent(getCsrfToken()),
+    })
+    .then(r => r.json())
+    .then(data => {
+        if (data.success) {
+            showToast('success', 'Agent key regenerated.');
+            setTimeout(() => location.reload(), 1500);
+        } else {
+            showToast('error', data.error || 'Failed to regenerate key.');
+        }
+    })
+    .catch(err => showToast('error', 'Request failed: ' + err.message));
+}
+
 function getCsrfToken() {
     return document.querySelector('meta[name="csrf-token"]')?.content || '';
 }