feat: add background renewal caching with 5m ttl

Co-authored-by: aider (openrouter/thinkingmachines/inkling-small:free) <aider@aider.chat>

backend/main.py

@@ -3,6 +3,7 @@ from fastapi.middleware.cors import CORSMiddleware
 import subprocess
 import time
 import json
+import threading
 
 app = FastAPI()
 
@@ -16,6 +17,7 @@ app.add_middleware(
 
 cache = {}
 CACHE_TTL = 300  # 5 minutes
+cache_lock = threading.Lock()
 
 def run_kubectl(args, context=None):
     cmd = ["kubectl"]
@@ -30,15 +32,45 @@ def get_cache_key(resource, namespace, context):
 
 def get_cached_items(resource, namespace, context):
     key = get_cache_key(resource, namespace, context)
-    if key in cache:
-        ts, items = cache[key]
-        if time.time() - ts < CACHE_TTL:
-            return items
+    with cache_lock:
+        if key in cache:
+            ts, items = cache[key]
+            if time.time() - ts < CACHE_TTL:
+                return items
     return None
 
 def set_cached_items(resource, namespace, context, items):
     key = get_cache_key(resource, namespace, context)
-    cache[key] = (time.time(), items)
+    with cache_lock:
+        cache[key] = (time.time(), items)
+
+def refresh_worker(resource, namespace, context, kubectl_args, item_mapper):
+    while True:
+        try:
+            result = run_kubectl(kubectl_args, context=context)
+            try:
+                obj = json.loads(result.stdout)
+                raw_items = obj.get("items", [])
+            except Exception:
+                raw_items = []
+            items = [item_mapper(i) for i in raw_items]
+            set_cached_items(resource, namespace, context, items)
+        except Exception:
+            pass
+        time.sleep(240)  # 4 minutes background renewal
+
+@app.on_event("startup")
+def start_background_refresh():
+    # Background renewal for common default namespace / no context
+    workers = [
+        ("pods", "default", None, ["get", "pods", "-n", "default", "-o", "json"], lambda i: {"name": i.get("metadata", {}).get("name", "unknown"), "namespace": i.get("metadata", {}).get("namespace", "default")}),
+        ("nodes", "default", None, ["get", "nodes", "-o", "json"], lambda i: {"name": i.get("metadata", {}).get("name", "unknown"), "namespace": "-"}),
+        ("pvcs", "default", None, ["get", "pvc", "-n", "default", "-o", "json"], lambda i: {"name": i.get("metadata", {}).get("name", "unknown"), "namespace": i.get("metadata", {}).get("namespace", "default")}),
+        ("configmaps", "default", None, ["get", "configmaps", "-n", "default", "-o", "json"], lambda i: {"name": i.get("metadata", {}).get("name", "unknown"), "namespace": i.get("metadata", {}).get("namespace", "default")}),
+    ]
+    for res, ns, ctx, args, mapper in workers:
+        t = threading.Thread(target=refresh_worker, args=(res, ns, ctx, args, mapper), daemon=True)
+        t.start()
 
 @app.get("/")
 def root():