Force startup initialization to happen early.

run_server.py

@@ -2,8 +2,13 @@
 """ Run the Flask backend server. """
 
 import os
+import threading
+import urllib.request
+import time
 import glob
 
+from flask import url_for
+
 # ---------------------------------------------------------------------
 
 # monitor extra files for changes
@@ -21,8 +26,33 @@ for fspec in ["config","static","templates"] :
         files = glob.glob( fspec )
     extra_files.extend( files )
 
-# run the server
+# initialize
 from asl_articles import app
+
+# FUDGE! Startup can take some time (e.g. because we have to build the search index over a large database),
+# and since we do that on first request, it's annoying to have started the server up, if we don't do that
+# first request immediately, the server sits there idling, when it could be doing that startup initialization,
+# and we then have to wait when we eventually do that first request.
+# We fix this by doing the first request ourself here (something harmless).
+def _force_init():
+    time.sleep( 5 )
+    try:
+        # figoure out the URL for the request we're going to make
+        with app.test_request_context() as req:
+            url = url_for( "ping" )
+            host = req.request.host_url
+        # FUDGE! There doesn't seem to be a way to get the port number Flask is listening on :-/
+        port = app.config.get( "FLASK_PORT_NO", 5000 )
+        if host.endswith( "/" ):
+            host = host[:-1]
+        url = "{}:{}{}".format( host, port, url )
+        # make the request
+        _ = urllib.request.urlopen( url ).read()
+    except Exception as ex: #pylint: disable=broad-except
+        print( "WARNING: Startup ping failed: {}".format( ex ) )
+threading.Thread( target=_force_init ).start()
+
+# run the server
 app.run(
     host = app.config.get( "FLASK_HOST", "localhost" ),
     port = app.config.get( "FLASK_PORT_NO" ),