Add maxConnection environment configuration, have it default to 128

The number gives the maximum number of contemporary connections and
is dimensioned on the limit of open file descriptors found to be
needed on a per-connection basis.

app.js

@@ -33,7 +33,15 @@ var Windshaft = require('windshaft');
 var serverOptions = require('./lib/cartodb/server_options');
 
 ws = CartodbWindshaft(serverOptions);
+
+// Maximum number of connections for one process
+// 128 is a good number if you have up to 1024 filedescriptors
+// 4 is good if you have max 32 filedescriptors
+// 1 is good if you have max 16 filedescriptors
+ws.maxConnections = global.environment.maxConnections || 128;
+
 ws.listen(global.environment.port, global.environment.host);
+
 ws.on('listening', function() {
   console.log("Windshaft tileserver started on " + global.environment.host + ':' + global.environment.port);
 });

cluster.js

@@ -36,6 +36,9 @@ var serverOptions = require('./lib/cartodb/server_options');
 
 var ws = CartodbWindshaft(serverOptions);
 
+// Maximum number of connections for one process (see apps.js)
+ws.maxConnections = global.environment.maxConnections || 128;
+
 //.use(cluster.logger('logs'))
 //.use(cluster.stats())
 //.use(cluster.pidfiles('pids'))

config/environments/development.js.example

@@ -2,6 +2,9 @@ var config = {
      environment: 'development'
     ,port: 8181
     ,host: '127.0.0.1'
+    // Maximum number of connections for one process
+    // 128 is a good value with a limit of 1024 open file descriptors
+    ,maxConnections:128
     // idle socket timeout, in miliseconds 
     ,socket_timeout: 600000
     ,enable_cors: true

config/environments/production.js.example

@@ -2,6 +2,9 @@ var config = {
     environment: 'production'
     ,port: 8181
     ,host: '127.0.0.1'
+    // Maximum number of connections for one process
+    // 128 is a good value with a limit of 1024 open file descriptors
+    ,maxConnections:128
     // idle socket timeout, in miliseconds
     ,socket_timeout: 600000 
     ,enable_cors: true

config/environments/staging.js.example

@@ -2,6 +2,9 @@ var config = {
     environment: 'production'
     ,port: 8181
     ,host: '127.0.0.1'
+    // Maximum number of connections for one process
+    // 128 is a good value with a limit of 1024 open file descriptors
+    ,maxConnections:128
     // idle socket timeout, in miliseconds
     ,socket_timeout: 600000 
     ,enable_cors: true

config/environments/test.js.example

@@ -2,6 +2,9 @@ var config = {
      environment: 'test'
     ,port: 8888
     ,host: '127.0.0.1'
+    // Maximum number of connections for one process
+    // 128 is a good value with a limit of 1024 open file descriptors
+    ,maxConnections:128
     // idle socket timeout, in miliseconds
     ,socket_timeout: 600000 
     ,enable_cors: true