Missing statistics.js

statistics.js

@@ -0,0 +1,71 @@
+"use strict";
+
+var MA = require('moving-average');
+var _ = require('underscore');
+
+var logger = require('./logger');
+exports.stats = {};
+
+exports.emit = function(type, value, err, meta) {
+  if(!meta) {
+    meta = {};
+  }
+  meta.type = type;
+  meta.value = value;
+  if(err) {
+    meta.error = err;
+  }
+  if(err) {
+    logger.info('stat_error', 'measured', meta);
+  }
+  else {
+    logger.info('stat', 'measured', meta);
+  }
+  var now = Date.now();
+  if(!exports.stats[type]) {
+    exports.stats[type] = {
+      ma1s: MA(1000),
+      ma1m: MA(60 * 1000),
+      ma1h: MA(60 * 60 * 1000),
+      ma1d: MA(24 * 60 * 60 * 1000),
+      ma1s_error: MA(1000),
+      ma1m_error: MA(60 * 1000),
+      ma1h_error: MA(60 * 60 * 1000),
+      ma1d_error: MA(24 * 60 * 60 * 1000)
+    };
+  }
+  var stat = exports.stats[type];
+  if(value) {
+    stat.lastTime = now;
+    stat.lastValue = value;
+    stat.ma1s.push(now, value);
+    stat.ma1m.push(now, value);
+    stat.ma1h.push(now, value);
+    stat.ma1d.push(now, value);
+  }
+  if(err) {
+    stat.lastErrorTime = now;
+  }
+  var errval = err ? 0 : 1;
+  stat.ma1s_error.push(now, errval);
+  stat.ma1m_error.push(now, errval);
+  stat.ma1h_error.push(now, errval);
+  stat.ma1d_error.push(now, errval);
+};
+
+exports.getStatistics = function() {
+  return _.reduce(exports.stats, function(memo, stat, key) {
+    memo[key] = {
+      lastTime: new Date(stat.lastTime).toISOString(),
+      lastValue: stat.lastValue,
+      lastErrorTime: stat.lastErrorTime ? new Date(stat.lastErrorTime).toISOString() : undefined
+    };
+    ['ma1s', 'ma1m', 'ma1h', 'ma1d'].forEach(function(ma) {
+      memo[key][ma] = {
+        movingAverage: stat[ma].movingAverage(),
+        variance: stat[ma].variance()
+      };
+    });
+    return memo;
+  }, {});
+};