perf: use two-second minimum Raspberry Pi collection cadence

plugin/worker.py

@@ -56,6 +56,14 @@ def request(device, endpoint, method='GET', payload=None, query=None):
         raise AdapterError('RESULT_UNKNOWN' if method == 'PUT' else 'DEVICE_UNAVAILABLE') from None
 
 
+def collection_interval(value):
+    declaration = value.get('collection', {})
+    interval = declaration.get('interval_seconds') if isinstance(declaration, dict) else None
+    if not isinstance(interval, (int, float)) or isinstance(interval, bool) or not math.isfinite(interval) or not 1 <= interval <= 3600:
+        interval = MANIFEST['collection']['interval_seconds']
+    return max(MANIFEST['collection']['interval_seconds'], interval)
+
+
 def collect(device):
     value = request(device, '/status')
     if not isinstance(value.get('system'), dict) or not isinstance(value.get('machine'), dict):
@@ -88,7 +96,7 @@ def collect(device):
     return {'schema_version': 1, 'observed_at': value.get('timestamp'),
             'identity': {'reported_name': value['machine'].get('name'), 'category': 'host',
                          'details': value.get('device', {})},
-            'collection': value.get('collection', MANIFEST['collection']),
+            'collection': {'interval_seconds': collection_interval(value)},
             'capabilities': MANIFEST['capabilities'], 'metrics': metrics,
             'resources': [{'id': 'host', 'type': 'host'}],
             'alerts': value.get('display', {}).get('alerts', []),