Add single-switch scan

New "Scan Switch" header button reuses the Test Connection picker and
posts to /api/scan/switch, which runs the normal scan pipeline on one
switch from the NocoDB inventory. Like a dept scan it does not clear
links first, so the rest of the map is left in place.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

app.py

@@ -37,11 +37,12 @@ def _reschedule(interval_minutes):
     logger.info(f"Auto-scan scheduled every {interval_minutes} minutes")
 
 
-def _trigger_scan_background(dept: str = None, workers: int = 5, login_delay: int = 3):
+def _trigger_scan_background(dept: str = None, workers: int = 5, login_delay: int = 3, only_ip: str = None):
     """Run scan in a background thread. dept=None → all switches."""
     if not scanner.scan_state["running"]:
         t = threading.Thread(target=scanner.run_scan,
-                             kwargs={"dept": dept, "workers": workers, "login_delay": login_delay},
+                             kwargs={"dept": dept, "workers": workers, "login_delay": login_delay,
+                                     "only_ip": only_ip},
                              daemon=True)
         t.start()
 
@@ -132,6 +133,25 @@ def api_scan_ami():
     return jsonify({"status": "started", "dept": "AMI"})
 
 
+@app.route("/api/scan/switch", methods=["POST"])
+def api_scan_switch():
+    """Scan a single switch (by IP, must be in the NocoDB inventory)."""
+    if scanner.scan_state["running"]:
+        return jsonify({"error": "Scan already running"}), 409
+    ip = ((request.get_json(silent=True) or {}).get("ip") or "").strip()
+    if not ip:
+        return jsonify({"error": "ip is required"}), 400
+    try:
+        known = any(s["ip"] == ip for s in get_switches())
+    except RuntimeError as e:
+        return jsonify({"error": str(e)}), 502
+    if not known:
+        return jsonify({"error": f"{ip} is not an active switch in NocoDB"}), 404
+    workers, login_delay = _scan_params()
+    _trigger_scan_background(workers=workers, login_delay=login_delay, only_ip=ip)
+    return jsonify({"status": "started", "ip": ip})
+
+
 @app.route("/api/scan/abort", methods=["POST"])
 def api_scan_abort():
     """Request the in-progress scan to stop after in-flight switches finish."""

index.html

@@ -611,6 +611,10 @@ var Xr=function(e){if(!(this instanceof Xr))return new Xr(e);this.id="Thenable/1
     <svg width="14" height="14" fill="none" stroke="currentColor" stroke-width="2.5" viewBox="0 0 24 24"><path d="M4 14a8 8 0 0116 0M4 14h16M4 14l-1 6h18l-1-6M12 14V6m0 0l-3 3m3-3l3 3"/></svg>
     Scan AMI
   </button>
+  <button class="btn btn-primary" id="scanOneBtn" onclick="openTestConnModal('scan')" title="Scan a single switch without touching the rest of the map">
+    <svg width="14" height="14" fill="none" stroke="currentColor" stroke-width="2.5" viewBox="0 0 24 24"><circle cx="11" cy="11" r="7"/><path d="M21 21l-4.3-4.3"/></svg>
+    Scan Switch
+  </button>
   <button class="btn btn-danger" id="clearScanBtn" onclick="clearAndRescan()">
     <svg width="14" height="14" fill="none" stroke="currentColor" stroke-width="2.5" viewBox="0 0 24 24">
       <polyline points="3 6 5 6 21 6"/><path d="M19 6l-1 14H6L5 6"/><path d="M10 11v6m4-6v6"/><path d="M9 6V4h6v2"/>
@@ -725,7 +729,7 @@ var Xr=function(e){if(!(this instanceof Xr))return new Xr(e);this.id="Thenable/1
 
   <div class="modal" id="testConnModal" style="display:none">
     <div class="modal-header">
-      <span>Test Connection</span>
+      <span id="testConnTitle">Test Connection</span>
       <button class="modal-close" onclick="closeModals()">✕</button>
     </div>
     <div class="modal-body">
@@ -735,7 +739,7 @@ var Xr=function(e){if(!(this instanceof Xr))return new Xr(e);this.id="Thenable/1
     </div>
     <div class="modal-footer">
       <button class="btn-sm" onclick="closeModals()">Cancel</button>
-      <button class="btn btn-primary" id="testConnRunBtn" onclick="runTestConnection()">Test</button>
+      <button class="btn btn-primary" id="testConnRunBtn" onclick="switchPickerMode === 'scan' ? runScanOne() : runTestConnection()">Test</button>
     </div>
   </div>
 
@@ -1120,7 +1124,13 @@ async function saveCredentials() {
   msg.className = 'modal-msg ok';
 }
 
-async function openTestConnModal() {
+// The switch picker modal serves both Test Connection and Scan Switch.
+let switchPickerMode = 'test';
+
+async function openTestConnModal(mode = 'test') {
+  switchPickerMode = mode;
+  document.getElementById('testConnTitle').textContent = mode === 'scan' ? 'Scan One Switch' : 'Test Connection';
+  document.getElementById('testConnRunBtn').textContent = mode === 'scan' ? 'Scan' : 'Test';
   document.getElementById('modalOverlay').classList.add('visible');
   document.getElementById('testConnModal').style.display = 'block';
   const result = document.getElementById('testConnResult');
@@ -1178,6 +1188,31 @@ async function runTestConnection() {
   }
 }
 
+async function runScanOne() {
+  const sel = document.getElementById('testConnSelect');
+  const opt = sel.options[sel.selectedIndex];
+  const result = document.getElementById('testConnResult');
+  if (!opt || !opt.value) {
+    result.className = 'modal-msg fail';
+    result.textContent = 'No switch selected';
+    return;
+  }
+  const res = await fetch('/api/scan/switch', {
+    method: 'POST',
+    headers: { 'Content-Type': 'application/json' },
+    body: JSON.stringify({ ip: opt.value, ...scanSettings() }),
+  });
+  if (res.status === 409) { alert('Scan already running'); return; }
+  if (!res.ok) {
+    const d = await res.json().catch(() => ({}));
+    result.className = 'modal-msg fail';
+    result.textContent = `✗ ${d.error || 'Scan failed to start'}`;
+    return;
+  }
+  closeModals();
+  startPolling();
+}
+
 function startPolling() {
   if (pollInterval) return;
   pollInterval = setInterval(pollStatus, 1500);
@@ -1201,6 +1236,7 @@ async function pollStatus() {
       document.getElementById('scanGwBtn').disabled = true;
       document.getElementById('scanSecBtn').disabled = true;
       document.getElementById('scanAmiBtn').disabled = true;
+      document.getElementById('scanOneBtn').disabled = true;
       document.getElementById('clearScanBtn').disabled = true;
       document.getElementById('abortScanBtn').style.display = '';
       progressWrap.classList.add('visible');
@@ -1266,6 +1302,7 @@ async function pollStatus() {
       document.getElementById('scanGwBtn').disabled = false;
       document.getElementById('scanSecBtn').disabled = false;
       document.getElementById('scanAmiBtn').disabled = false;
+      document.getElementById('scanOneBtn').disabled = false;
       document.getElementById('clearScanBtn').disabled = false;
       document.getElementById('abortScanBtn').style.display = 'none';
       progressBar.style.width = '100%';

scanner.py

@@ -39,10 +39,12 @@ def request_abort():
     return False
 
 
-def run_scan(dept: str = None, workers: int = 5, login_delay: int = 3):
+def run_scan(dept: str = None, workers: int = 5, login_delay: int = 3, only_ip: str = None):
     """
     Full scan: fetch switch IPs from NocoDB → SSH all → parse → store → export.
     dept: None = all active switches, "ELEC" or "GW" = dept-filtered.
+    only_ip: scan just that one switch from the list; like a dept scan, it
+    leaves every other switch's links in place.
     """
     global scan_state
 
@@ -54,6 +56,8 @@ def run_scan(dept: str = None, workers: int = 5, login_delay: int = 3):
 
     # Fetch switch list from NocoDB (or fallback)
     switches = get_switches(dept=dept)
+    if only_ip:
+        switches = [s for s in switches if s["ip"] == only_ip]
 
     if not switches:
         logger.error("NocoDB returned no switches — aborting scan.")
@@ -72,13 +76,13 @@ def run_scan(dept: str = None, workers: int = 5, login_delay: int = 3):
         "fail": 0,
         "errors": [],
         "log_lines": [],
-        "dept_filter": dept,
+        "dept_filter": dept or only_ip,
         "aborted": False,
     })
 
     scan_id = log_scan_start()
-    if dept is None:
+    if dept is None and only_ip is None:
-        clear_links()  # Full scan only — dept scans upsert without wiping other depts
+        clear_links()  # Full scan only — dept/single-switch scans upsert without wiping the rest
 
     def on_progress(done, total, ip, result):
         from datetime import datetime