From dab8b072fa0844eb189f60cbaf97008764296fa7 Mon Sep 17 00:00:00 2001
From: vmarchaud <contact@vmarchaud.fr>
Date: Wed, 21 Jun 2017 13:33:47 +0200
Subject: [PATCH] (interactor) implement a 30 ttl for cached file in ram
 (#2763)

---
 lib/Interactor/PushInteractor.js |  7 ++--
 lib/Interactor/Utility.js        | 59 ++++++++++++++++++++++++--------
 test/interface/cache.mocha.js    | 25 ++++++++++++++
 3 files changed, 73 insertions(+), 18 deletions(-)

diff --git a/lib/Interactor/PushInteractor.js b/lib/Interactor/PushInteractor.js
index 0e0cfd8d..0f67ed21 100644
--- a/lib/Interactor/PushInteractor.js
+++ b/lib/Interactor/PushInteractor.js
@@ -129,9 +129,10 @@ var PushInteractor = module.exports = {
           debug('Error while trying to get file from FS : %s', err.message || err)
           return undefined;
         }
-      }
-    })
-    self.stackParser = new InteractorUtility.StackTraceParser({ cache: self.cache, context: cst.CONTEXT_ON_ERROR});
+      },
+      ttl: 60 * 30
+    });
+    self.stackParser = new InteractorUtility.StackTraceParser({ cache: self.cache, context: cst.CONTEXT_ON_ERROR });
     self.aggregator = new Aggregator(self);
     self.aggregator.init();
   },
diff --git a/lib/Interactor/Utility.js b/lib/Interactor/Utility.js
index 951c33b0..25014057 100644
--- a/lib/Interactor/Utility.js
+++ b/lib/Interactor/Utility.js
@@ -32,23 +32,49 @@ EWMA.prototype.rate = function (timeUnit) {
   return (this._rate || 0) * timeUnit
 }
 
+var moment = require('moment');
+
 /**
  * Simple cache implementation
  *
  * @param {Object} opts cache options
+ * @param {Integer} opts.ttl time to live of all the keys
  * @param {Function} opts.miss function called when a key isn't found in the cache
  */
 function Cache (opts) {
-  this._cache = {}
-  this._miss = opts.miss
+  this._cache = {};
+  this._miss = opts.miss;
+  this._ttl_time = opts.ttl;
+  this._ttl = {};
+
+  if (opts.ttl) {
+    setInterval(this._worker.bind(this), 1000);
+  }
 }
 
+/**
+ * Task running to check TTL and potentially remove older key
+ */
+Cache.prototype._worker = function () {
+  var keys = Object.keys(this._ttl);
+  for (var i = 0; i < keys.length; i++) {
+    var key = keys[i];
+    var value = this._ttl[key];
+    if (moment().isAfter(value)) {
+      delete this._cache[key];
+      delete this._ttl[key];
+    }
+  }
+};
+
 /**
  * Empty the cache
  */
 Cache.prototype.reset = function () {
   this._cache = null;
   this._cache = {};
+  this._ttl = null;
+  this._ttl = {};
 };
 
 /**
@@ -57,17 +83,17 @@ Cache.prototype.reset = function () {
  * @param {String} key
  */
 Cache.prototype.get = function (key) {
-  if (!key) return null
-  var value = this._cache[key]
-  if (value) return value
+  if (!key) return null;
+  var value = this._cache[key];
+  if (value) return value;
 
-  value = this._miss(key)
+  value = this._miss(key);
 
-  if (value)
-    this.set(key, value)
-
-  return value
-}
+  if (value) {
+    this.set(key, value);
+  }
+  return value;
+};
 
 /**
  * Set a value in the cache
@@ -76,10 +102,13 @@ Cache.prototype.get = function (key) {
  * @param {Mixed} value
  */
 Cache.prototype.set = function (key, value) {
-  if (!key || !value) return false
-  this._cache[key] = value
-  return true
-}
+  if (!key || !value) return false;
+  this._cache[key] = value;
+  if (this._ttl_time) {
+    this._ttl[key] = moment().add(this._ttl_time, 'seconds');
+  }
+  return true;
+};
 
 /**
  * StackTraceParser is used to parse callsite from stacktrace
diff --git a/test/interface/cache.mocha.js b/test/interface/cache.mocha.js
index 7467ae61..bfcd9d8c 100644
--- a/test/interface/cache.mocha.js
+++ b/test/interface/cache.mocha.js
@@ -58,4 +58,29 @@ describe('Cache Utility', function() {
     should(cache.get('toto')).be.null();
   });
 
+  it('should instanciate context cache with ttl', function() {
+    cache = new Utility.Cache({
+      miss: function (key) {
+        try {
+          var content = fs.readFileSync(path.resolve(key));
+          return content.toString().split(/\r?\n/);
+        } catch (err) {
+          return null;
+        }
+      },
+      ttl: 1
+    });
+  });
+
+  it('should add a key', function () {
+    should(cache.set('toto', 'yeslife')).be.true();
+  });
+
+  it('should wait one second to see the key disapear', function (done) {
+    setTimeout(function () {
+      should(cache.get('toto')).be.null();
+      done();
+    }, 1000);
+  });
+
 });