Patch for issue #41

README.md

@@ -34,6 +34,29 @@ To start processing your jobs, somewhere in your project add:
 SyncedCron.start();
 ```
 
+If you want a job to run only once or a limited number of times, you can either remove it inside the job function or create a limited schedule:
+
+```javascript
+SyncedCron.add({
+  name: 'myJob',
+  schedule: function(parser) {
+    // EITHER set a limited schedule
+    var date = new Date;
+    date.setHours(date.getHours() + 12);
+
+    // (this Later.js object only contains a single event)
+    return parser.recur().on(date).fullDate();
+  }, 
+  job: function() {
+    // (do something)
+
+    // ... OR remove the job inside function
+    SyncedCron.remove('myJob');
+  }
+});
+```
+
+
 ### Advanced
 
 SyncedCron uses a collection called `cronHistory` to syncronize between processes. This also serves as a useful log of when jobs ran along with their output or error. A sample item looks like:

synced-cron-server.js

@@ -101,7 +101,7 @@ Meteor.startup(function() {
 var scheduleEntry = function(entry) {
   var schedule = entry.schedule(Later.parse);
   entry._timer =
-    SyncedCron._laterSetInterval(SyncedCron._entryWrapper(entry), schedule);
+    SyncedCron._laterSetInterval(SyncedCron._entryWrapper(entry), schedule, entry.name);
 
   log.info('Scheduled "' + entry.name + '" next run @'
     + Later.schedule(schedule).next(1));
@@ -238,20 +238,22 @@ SyncedCron._reset = function() {
 //   between multiple, potentially laggy and unsynced machines
 
 // From: https://github.com/bunkat/later/blob/master/src/core/setinterval.js
-SyncedCron._laterSetInterval = function(fn, sched) {
+SyncedCron._laterSetInterval = function(fn, sched, name) {
 
-  var t = SyncedCron._laterSetTimeout(scheduleTimeout, sched),
+  var t = SyncedCron._laterSetTimeout(scheduleTimeout, sched, name),
       done = false;
 
   /**
   * Executes the specified function and then sets the timeout for the next
   * interval.
   */
   function scheduleTimeout(intendedAt) {
-    if(!done) {
+    if (!done)
       fn(intendedAt);
-      t = SyncedCron._laterSetTimeout(scheduleTimeout, sched);
-    }
+
+    // Check for done again, in case entry is removed inside job function body
+    if (!done)
+      t = SyncedCron._laterSetTimeout(scheduleTimeout, sched, name);
   }
 
   return {
@@ -269,7 +271,7 @@ SyncedCron._laterSetInterval = function(fn, sched) {
 };
 
 // From: https://github.com/bunkat/later/blob/master/src/core/settimeout.js
-SyncedCron._laterSetTimeout = function(fn, sched) {
+SyncedCron._laterSetTimeout = function(fn, sched, name) {
 
   var s = Later.schedule(sched), t;
   scheduleTimeout();
@@ -281,21 +283,29 @@ SyncedCron._laterSetTimeout = function(fn, sched) {
   */
   function scheduleTimeout() {
     var now = Date.now(),
-        next = s.next(2, now),
-        diff = next[0].getTime() - now,
-        intendedAt = next[0];
-
-    // minimum time to fire is one second, use next occurrence instead
-    if(diff < 1000) {
-      diff = next[1].getTime() - now;
-      intendedAt = next[1];
-    }
+        next = s.next(2, now);
 
-    if(diff < 2147483647) {
-      t = Meteor.setTimeout(function() { fn(intendedAt); }, diff);
+    if (next) {
+      var diff = next[0].getTime() - now,
+          intendedAt = next[0];
+
+      // minimum time to fire is one second, use next occurrence instead
+      if(next[1] && diff < 1000) {
+        diff = next[1].getTime() - now;
+        intendedAt = next[1];
+      }
+
+      if(diff < 2147483647) {
+        t = Meteor.setTimeout(function() { fn(intendedAt); }, diff);
+      }
+      else {
+        t = Meteor.setTimeout(scheduleTimeout, 2147483647);
+      }
     }
     else {
-      t = Meteor.setTimeout(scheduleTimeout, 2147483647);
+      log.info('SyncedCron: No more future events for "' + name + '".');
+
+      SyncedCron.remove(name);
     }
   }
 

synced-cron-tests.js

@@ -183,3 +183,45 @@ Tinytest.addAsync('SyncedCron should pass correct arguments to logger', function
 
   SyncedCron.options.logger = null;
 });
+
+
+/*
+  Unfinished tests
+*/
+
+Tinytest.add('Removing current entry inside job prevents the next event from running', function(test) {
+  //! Preparation
+
+  SyncedCron.add({
+    name: "testRemove",
+    schedule: function (parser) {
+      return parser.recur().every(1).second();
+    },
+    job: function () {
+      console.log("TEST");
+      SyncedCron.remove("testRemove");
+    }
+  });
+
+  //! Should test that "TEST" is only output to log once
+});
+
+Tinytest.add('Automatically remove entry after last event in schedule has been triggered', function(test) {
+  //! Preparation
+
+  SyncedCron.add({
+    name: "testRemove",
+    schedule: function (parser) {
+      var date = new Date;
+      date.setSeconds(date.getSeconds() + 2);
+
+      return parser.recur().on(date).fullDate();
+    },
+    job: function () {
+      console.log("TEST");
+    }
+  });
+
+  //! Should test that "TEST" is only output to log once
+  // and that "testRemove" is removed after 2 seconds
+});