From af744fad896ffba2f78a7fd1721fe6887c466d2d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Kier=C3=A1n=20Meinhardt?= <kmein@posteo.de>
Date: Tue, 4 Oct 2022 19:16:58 +0200
Subject: reaktor2: add cache to krebsfood hook

---
 krebs/2configs/reaktor2.nix | 31 ++++++++++++++++++++++++-------
 1 file changed, 24 insertions(+), 7 deletions(-)

(limited to 'krebs/2configs/reaktor2.nix')

diff --git a/krebs/2configs/reaktor2.nix b/krebs/2configs/reaktor2.nix
index 9d738813..33d7ad27 100644
--- a/krebs/2configs/reaktor2.nix
+++ b/krebs/2configs/reaktor2.nix
@@ -79,17 +79,34 @@ let
           pattern = "18@p";
           activate = "match";
           command = {
-            env.radius = toString 250; # metres around c-base to search
+            env = {
+              radius = toString 250; # metres around c-base to search
+              age_threshold = toString (24 * 60 * 60);
+              state_file = "${stateDir}/krebsfood";
+            };
             filename = pkgs.writeDash "krebsfood" ''
               set -efu
               expected_max_results=1024 # the upper bound on the number of restaurants
 
-              echo '[out:json];node(id:260050809)->.cbase;
-              (
-                node(around.cbase:'$radius')[amenity=fast_food];
-                node(around.cbase:'$radius')[amenity=restaurant];
-              );out;' \
-                | ${pkgs.curl}/bin/curl -sSL -d @- -X POST http://overpass-api.de/api/interpreter \
+              file_age_seconds() {
+                expr "$(date +%s)" - "$(date +%s -r "$1")"
+              }
+
+              get_restaurants() {
+                if [ -f "$state_file" ]; then
+                  [ "$(file_age_seconds "$state_file")" -lt "$age_threshold" ] && cat "$state_file"
+                else
+                  echo '[out:json];node(id:260050809)->.cbase;
+                    (
+                      node(around.cbase:'$radius')[amenity=fast_food];
+                      node(around.cbase:'$radius')[amenity=restaurant];
+                    );out;' \
+                      | ${pkgs.curl}/bin/curl -sSL -d @- -X POST http://overpass-api.de/api/interpreter \
+                      | tee "$state_file"
+                fi
+              }
+
+              get_restaurants \
                 | ${pkgs.jq}/bin/jq -r --argjson random "$(shuf -i 0-$expected_max_results -n 1)" '
                   .elements
                   | length as $length
-- 
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