From 01a321c202a1a83550b2bc3b8c50c513f3308d55 Mon Sep 17 00:00:00 2001
From: Igor Chubin <igor@chub.in>
Date: Thu, 7 May 2020 23:37:21 +0200
Subject: [PATCH] png rendering in a separate thread

---
 lib/wttr_srv.py | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/lib/wttr_srv.py b/lib/wttr_srv.py
index 3b2f89a..ca42f90 100644
--- a/lib/wttr_srv.py
+++ b/lib/wttr_srv.py
@@ -9,6 +9,7 @@ import logging
 import io
 import os
 import time
+from gevent.threadpool import ThreadPool
 from flask import render_template, send_file, make_response
 
 import fmt.png
@@ -36,6 +37,8 @@ logging.basicConfig(filename=LOG_FILE, level=logging.INFO, format='%(asctime)s %
 
 LIMITS = Limits(whitelist=[MY_EXTERNAL_IP], limits=QUERY_LIMITS)
 
+TASKS = ThreadPool(25)
+
 def show_text_file(name, lang):
     """
     show static file `name` for `lang`
@@ -212,8 +215,14 @@ def _response(parsed_query, query, fast_mode=False):
         output = get_wetter(parsed_query)
 
     if parsed_query.get('png_filename'):
-        output = fmt.png.render_ansi(
-            output, options=parsed_query)
+        # originally it was just a usual function call,
+        # but it was a blocking call, so it was moved
+        # to separate threads:
+        #
+        #    output = fmt.png.render_ansi(
+        #        output, options=parsed_query)
+        result = TASKS.spawn(fmt.png.render_ansi, output, options=parsed_query)
+        output = result.get()
     else:
         if query.get('days', '3') != '0' \
             and not query.get('no-follow-line') \