Split drawtime/srcbytes stat handling + cookie encoding into its own …

…lib with tests.

app/lib.js

@@ -43,6 +43,7 @@ var statHandler = function(key) {
   return _(function() {
     if (document.cookie.indexOf(key) === -1) return;
     var max = 300;
+
     var stats = _(document.cookie
       .split(key + '=').pop()
       .split(';').shift()

lib/server.js

@@ -6,6 +6,7 @@ var fs = require('fs');
 var url = require('url');
 var source = require('./source');
 var style = require('./style');
+var stats = require('./stats');
 var middleware = require('./middleware');
 var express = require('express');
 var cors = require('cors');
@@ -175,21 +176,11 @@ function tile(req, res, next) {
             return next(err);
         }
 
-        // Set drawtime cookie for a given style.
-        style.stats(id, 'drawtime', z, data._drawtime);
-        res.cookie('drawtime', _(style.stats(id, 'drawtime'))
-            .reduce(function(memo, stat, z) {
-                memo.push([z,stat.min,stat.avg|0,stat.max].join('-'));
-                return memo;
-            }, []).join('.'));
-
-        // Set srcbytes cookie for a given style.
-        style.stats(id, 'srcbytes', z, data._srcbytes);
-        res.cookie('srcbytes', _(style.stats(id, 'srcbytes')).
-            reduce(function(memo, stat, z) {
-                memo.push([z,stat.min,stat.avg|0,stat.max].join('-'));
-                return memo;
-            }, []).join('.'));
+        // Set drawtime/srcbytes cookies.
+        stats.set(source, 'drawtime', z, data._drawtime);
+        stats.set(source, 'srcbytes', z, data._srcbytes);
+        res.cookie('drawtime', stats.cookie(source, 'drawtime'));
+        res.cookie('srcbytes', stats.cookie(source, 'srcbytes'));
 
         // Clear out tile errors.
         res.cookie('errors', '');

lib/stats.js

@@ -0,0 +1,37 @@
+module.exports = {};
+module.exports.get = get;
+module.exports.set = set;
+module.exports.cookie = cookie;
+
+// Get stats.
+function get(source, key) {
+    source.stats = source.stats || {};
+    source.stats[key] = source.stats[key] || {};
+    return source.stats[key];
+}
+
+// Set stats for a given zoom level.
+function set(source, key, z, val) {
+    source.stats = source.stats || {};
+    source.stats[key] = source.stats[key] || {};
+    source.stats[key][z] = source.stats[key][z] || { count:0 };
+
+    var stats = source.stats[key][z];
+    stats.min = Math.min(val, stats.min||Infinity);
+    stats.max = Math.max(val, stats.max||0);
+    stats.avg = stats.count ? ((stats.avg * stats.count) + val) / (stats.count + 1) : val;
+    stats.count++;
+
+    return;
+}
+
+// Serialize stats into a cookie.
+function cookie(source, key) {
+    var stats = get(source, key);
+    var serialized = [];
+    for (var z in stats) {
+        serialized.push([z,stats[z].min,stats[z].avg|0,stats[z].max].join('-'));
+    }
+    return serialized.join('.');
+}
+

lib/style.js

@@ -442,22 +442,6 @@ style.toPackage = function(id, dest, callback) {
     }
 };
 
-// Set or get stats for a given zoom level.
-style.stats = function(id, key, z, val) {
-    if (!cache[id]) return false;
-    if ('number' === typeof z && val) {
-        cache[id].stats = cache[id].stats || {};
-        cache[id].stats[key] = cache[id].stats[key] || {};
-        cache[id].stats[key][z] = cache[id].stats[key][z] || { count:0 };
-        var stats = cache[id].stats[key][z];
-        stats.min = Math.min(val, stats.min||Infinity);
-        stats.max = Math.max(val, stats.max||0);
-        stats.avg = stats.count ? ((stats.avg * stats.count) + val) / (stats.count + 1) : val;
-        stats.count++;
-    }
-    return cache[id].stats[key];
-};
-
 // Set or get tile serving errors.
 style.error = function(id, err) {
     if (!cache[id]) return false;

test/stats.test.js

@@ -0,0 +1,40 @@
+var test = require('tape');
+var stats = require('../lib/stats');
+
+test('stats.set/get', function(t) {
+    var source = {};
+    t.equal(stats.set(source, 'drawtime', 0, 100), undefined, 'set');
+    t.deepEqual(stats.get(source, 'drawtime'), {
+        0: { count:1, avg:100, min:100, max:100 }
+    }, 'sets stats');
+
+    t.equal(stats.set(source, 'drawtime', 0, 200), undefined, 'set');
+    t.deepEqual(stats.get(source, 'drawtime'), {
+        0: { count:2, avg:150, min:100, max:200 }
+    }, 'calculates avg/min/max');
+
+    t.equal(stats.set(source, 'drawtime', 1, 200), undefined, 'set');
+    t.deepEqual(stats.get(source, 'drawtime'), {
+        0: { count:2, avg:150, min:100, max:200 },
+        1: { count:1, avg:200, min:200, max:200 }
+    }, 'segments by zoom');
+
+    t.equal(stats.set(source, 'srcbytes', 0, 200), undefined, 'set');
+    t.deepEqual(stats.get(source, 'drawtime'), {
+        0: { count:2, avg:150, min:100, max:200 },
+        1: { count:1, avg:200, min:200, max:200 }
+    }, 'segments by key');
+    t.deepEqual(stats.get(source, 'srcbytes'), {
+        0: { count:1, avg:200, min:200, max:200 }
+    }, 'segments by key');
+    t.end();
+});
+
+test('stats.cookie', function(t) {
+    var source = {};
+    t.equal(stats.set(source, 'drawtime', 0, 100), undefined, 'set');
+    t.equal(stats.set(source, 'drawtime', 1, 200), undefined, 'set');
+    t.equal(stats.cookie(source, 'drawtime'), '0-100-100-100.1-200-200-200', 'serializes cookie');
+    t.end();
+});
+