add route to trigger Populate

+ use instance keys to stop multiple instances of populate
+ move Populate error to a new file
+ misc

app/periodic_scan.py

@@ -7,7 +7,7 @@ from app.lib.populate import Populate, PopulateCancelledError
 from app.settings import SessionVarKeys, get_flag, get_scan_sleep_time
 from app.utils.generators import get_random_str
 from app.utils.threading import background
-
+from app.logger import log
 
 @background
 def run_periodic_scans():
@@ -25,6 +25,7 @@ def run_periodic_scans():
         try:
             Populate(instance_key=get_random_str())
         except PopulateCancelledError:
+            log.error("'run_periodic_scans': Periodic scan cancelled.")
             pass
 
         sleep_time = get_scan_sleep_time()