update pr/232 to be merge-able

docs/metric_types.md

@@ -38,6 +38,9 @@ generate the following list of stats for each threshold:
 Where `$KEY` is the stats key you specify when sending to statsd, and `$PCT` is
 the percentile threshold.
 
+If the count at flush is 0 then you can opt to send no metric at all for this timer,
+by setting `config.deleteTimers`.
+
 Use the `config.histogram` setting to instruct statsd to maintain histograms
 over time.  Specify which metrics to match and a corresponding list of
 ordered non-inclusive upper limits of bins (class intervals).
@@ -72,6 +75,9 @@ StatsD now also supports gauges, arbitrary values, which can be recorded.
 
     gaugor:333|g
 
+If the gauge is not updated at the next flush, it will send the previous value. You can opt to send
+no metric at all for this gauge, by setting `config.deleteGauge`
+
 Adding a sign to the gauge value will change the value, rather than setting it.
 
     gaugor:-10|g
@@ -92,6 +98,9 @@ using a Set to store all occuring events.
 
     uniques:765|s
 
+If the count at flush is 0 then you can opt to send no metric at all for this set, by
+setting `config.deleteSets`.
+
 Multi-Metric Packets
 --------------------
 StatsD supports receiving multiple metrics in a single packet by separating them

exampleConfig.js

@@ -34,6 +34,12 @@ Optional Variables:
     interval:       how often to log frequent keys [ms, default: 0]
     percent:        percentage of frequent keys to log [%, default: 100]
     log:            location of log file for frequent keys [default: STDOUT]
+  deleteIdleStats:  don't send values to graphite for inactive counters, sets, gauges, or timeers
+                    as opposed to sending 0.  For gauges, this unsets the gauge (instead of sending
+                    the previous value). Can be indivdually overriden. [default: false]
+  deleteGauges  :   don't send values to graphite for inactive gauges, as opposed to sending the previous value [default: false]
+  deleteTimers:     don't send values to graphite for inactive timers, as opposed to sending 0 [default: false]
+  deleteSets:       don't send values to graphite for inactive sets, as opposed to sending 0 [default: false]
   deleteCounters:   don't send values to graphite for inactive counters, as opposed to sending 0 [default: false]
   prefixStats:      prefix to use for the statsd statistics data for this running instance of statsd [default: statsd]
                     applies to both legacy and new namespacing

stats.js

@@ -59,6 +59,17 @@ function flushMetrics() {
 
   // After all listeners, reset the stats
   backendEvents.once('flush', function clear_metrics(ts, metrics) {
+    // TODO: a lot of this should be moved up into an init/constructor so we don't have to do it every
+    // single flushInterval....
+    // allows us to flag all of these on with a single config but still override them individually
+    conf.deleteIdleStats = conf.deleteIdleStats !== undefined ? conf.deleteIdleStats : false;
+    if (conf.deleteIdleStats) {
+      conf.deleteCounters = conf.deleteCounters !== undefined ? conf.deleteCounters : true;
+      conf.deleteTimers = conf.deleteTimers !== undefined ? conf.deleteTimers : true;
+      conf.deleteSets = conf.deleteSets !== undefined ? conf.deleteSets : true;
+      conf.deleteGauges = conf.deleteGauges !== undefined ? conf.deleteGauges : true;
+    }
+
     // Clear the counters
     conf.deleteCounters = conf.deleteCounters || false;
     for (var counter_key in metrics.counters) {
@@ -74,14 +85,33 @@ function flushMetrics() {
     }
 
     // Clear the timers
+    conf.deleteTimers = conf.deleteTimers || false;
     for (var timer_key in metrics.timers) {
-      metrics.timers[timer_key] = [];
-      metrics.timer_counters[timer_key] = 0;
+      if (conf.deleteTimers) {
+        delete(metrics.timers[timer_key]);
+        delete(metrics.timer_counters[timer_key]);
+      } else {
+        metrics.timers[timer_key] = [];
+        metrics.timer_counters[timer_key] = 0;
+     }
     }
 
     // Clear the sets
+    conf.deleteSets = conf.deleteSets || false;
     for (var set_key in metrics.sets) {
-      metrics.sets[set_key] = new set.Set();
+      if (conf.deleteSets) {
+        delete(metrics.sets[set_key]);
+      } else {
+        metrics.sets[set_key] = new set.Set();
+      }
+    }
+
+	// normally gauges are not reset.  so if we don't delete them, continue to persist previous value
+    conf.deleteGauges = conf.deleteGauges || false;
+    if (conf.deleteGauges) {
+      for (var gauge_key in metrics.gauges) {
+        delete(metrics.gauges[gauge_key]);
+      }
     }
   });
 
@@ -121,7 +151,7 @@ config.configFile(process.argv[2], function (config, oldConfig) {
     // key counting
     var keyFlushInterval = Number((config.keyFlush && config.keyFlush.interval) || 0);
 
-    var udp_version = config.address_ipv6 ? 'udp6' : 'udp4'
+    var udp_version = config.address_ipv6 ? 'udp6' : 'udp4';
     server = dgram.createSocket(udp_version, function (msg, rinfo) {
       backendEvents.emit('packet', msg, rinfo);
       counters[packets_received]++;

test/graphite_delete_counters_tests.js

@@ -1,3 +1,10 @@
+// this unit test, for deleteCounters and other stats related to deleteIdleStats
+// should probably be reviewed for sanity - I'm not sure it really tests appropriately
+// for example, it should test that data is written the first time
+// then test that the counter/etc is actually removed when it doesn't get data..
+// - keen99
+
+
 var fs           = require('fs'),
     net          = require('net'),
     temp         = require('temp'),
@@ -79,7 +86,7 @@ module.exports = {
                ,  port: 8125\n\
                ,  dumpMessages: false \n\
                ,  debug: false\n\
-               ,  deleteCounters: true\n\
+               ,  deleteIdleStats: true\n\
                ,  graphitePort: " + this.testport + "\n\
                ,  graphiteHost: \"127.0.0.1\"}";