added ttl

lib/cartodb/tile_cache.js

@@ -4,7 +4,8 @@
 // 'lru' implements a LRU cache
 
 var LRUCache       = require('./lru'),
-    CacheValidator = require('./cache_validator')
+    CacheValidator = require('./cache_validator'),
+    TTL            = require('./TTL');
 
 var BLANK_TILE_SIZE = 334; // totally transparent tile size in bytes
 
@@ -31,7 +32,7 @@ module.exports.LRUcache = function(max_items, redis_opts) {
 
 // implements a generic cache for tile
 // cache_policy should implement set and get methods and optionally getStats
-function GenericCache (cache_policy, cache_validator) {
+function GenericCache (cache_policy, cache_validator, ttl_timeout) {
 
     var me = {
         cache: cache_policy,
@@ -40,9 +41,16 @@ function GenericCache (cache_policy, cache_validator) {
         cache_misses: 0,
         cache_not_modified: 0,
         current_items: 0,
+        expired: 0,
         cache_invalidated: 0,
         max_items: 0
-    }
+    };
+
+    // enable ttl
+    var ttl = TTL(function(key) {
+        me.remove(key);
+        me.expired++;
+    }, ttl_timeout || 60);
 
     function cache_key(req) {
         return req.url;
@@ -55,6 +63,12 @@ function GenericCache (cache_policy, cache_validator) {
         }
     }
 
+    me.remove = function(key) {
+        ttl.remove(key);
+        me.cache.remove(key);
+        update_items(me.cache.size || 0);
+    }
+
     me.beforeTileRender = function(req, res, callback) {
         req.windshaft_start = new Date().getTime();
         var key = cache_key(req);
@@ -97,12 +111,14 @@ function GenericCache (cache_policy, cache_validator) {
     me.afterTileRender = function(req, res, tile, headers, callback) {
         var timestamp = new Date().getTime();
         var delta = timestamp - req.windshaft_start;
-        me.cache.put(cache_key(req), {
+        var key = cache_key(req);
+        me.cache.put(key, {
                 tile: tile,
                 headers: headers,
                 timestamp: timestamp/1000.0,
                 render_time: delta/1000.0,
                 hits: 0});
+        ttl.start(key);
         update_items(me.cache.size || 0);
         callback(null, tile, headers);
     }

lib/cartodb/ttl.js

@@ -0,0 +1,47 @@
+
+/*
+ ==========================================================
+ manages timeouts
+     * timeout in seconds
+     * on_delete will be called when time expired with the key as first param
+  
+  usage:
+    ttl = TTL(function(key) {
+        console.log("10 seconds expired on " + key");
+    }, 10);
+ ==========================================================
+*/
+function TTL(on_delete, timeout) {
+
+    var me = {
+        timeouts: {},
+        on_delete: on_delete,
+        timeout: timeout*1000
+    };
+
+    me.start = function(key) {
+        var t = me.timeouts[key];
+        if (t) {
+            clearTimeout(t);
+        }
+        me.timeouts[key] = setTimeout(
+            (function(k) {
+                return function() {
+                    me.on_delete(k);
+                };
+            })(key),
+            me.timeout);
+    }
+
+    me.remove = function(key) {
+        var t = me.timeouts[key];
+        if (t) {
+           clearTimeout(t);
+           delete me.timeouts[key];
+        }
+    }
+
+    return me;
+}
+
+module.exports = TTL;

test/unit/cartodb/ttl.test.js

@@ -0,0 +1,50 @@
+
+var assert = require('assert')
+  , _ = require('underscore')
+  , TTL = require('../../../lib/cartodb/ttl')
+  , tests = module.exports = {};
+
+
+tests['all ok'] = function() {
+    assert.ok(true, "ok");
+}
+
+tests['should timeout'] = function() {
+    var called = false;
+    var ttl = TTL(function() {
+        called = true;
+    }, 0.1);
+    ttl.start('test');
+    setTimeout(function() {
+        assert.ok(called === true, "called");
+    }, 200);
+}
+
+tests['should remove timeout'] = function() {
+    var called = false;
+    var ttl = TTL(function() {
+        called = true;
+    }, 0.1);
+    ttl.start('test');
+    ttl.remove('test');
+    setTimeout(function() {
+        assert.ok(called === false, "removed");
+    }, 200);
+}
+
+tests['should renew timeout time'] = function() {
+    var called = false;
+    var ttl = TTL(function() {
+        called = true;
+    }, 0.3);
+    ttl.start('test');
+    setTimeout(function() {
+        ttl.start('test');
+    }, 0.5);
+    setTimeout(function() {
+        assert.ok(called === false, "removed");
+    }, 300);
+    setTimeout(function() {
+        assert.ok(called === true, "removed");
+    }, 600);
+}