dev.enekoalonso.com » server

Having fun with node.js & Redis

Eneko Alonso — Fri, 01 Oct 2010 23:05:19 +0000

Last week I set up node.js for the first time. I did it on my Dreamhost shared server, but since that goes against the Terms of Service, I set up a small dedicated virtual server at RackspaceCloud.

My configuration uses:

Ubuntu 10.04.1
subversion
node.js
grasshopper
node_redis
redis

So far it’s been a lot of fun, I’ll give more details about the installation steps and configuration later on :)

May 6, 2010 -- Tech talks at LEVEL Studios (0)
February 19, 2010 -- Having fun with Mooml & Twitter (0)
February 28, 2009 -- Kyte’s REST API (0)
October 12, 2011 -- Command line scripting with Node.js (0)

MooTools Core for Server and Mobile Development

Eneko Alonso — Fri, 17 Sep 2010 17:50:30 +0000

One of the best things of MooTools is that it is very modular, from the core itself. This means you don’t need to include all core elements in your projects if you don’t want or don’t need some modules. For example, you may not want to include Array or Function, if you don’t need any enhancements of such objects.

In the case of server side or mobile applications (Titanium Developer and other Javascript based mobile frameworks), there is no browser involved which means there is no DOM. Thus, we can removed any kind of module that depend or are designed to work with this elements: Browser, Element, Selectors, Cookie… all those modules have no value for server side or mobile applications.

I found this page which summarizes the modules you should need for server or mobile development:

MooTools Core
Core: core
Native: Array, Function, Number, String, Hash
Class: Class, Class.Extras

MooTools More
Core: More
Class: Class.Refactor, Class.Binds, Class.Occludes

http://onecrayon.com/spice/docs/mootools-server/

Personally, I don’t find the MooTools More modules very useful, so I’m not including them in my projects. Maybe Binds would be a good addition, but it is not critical.

Having MooTools in a Javascript application makes it easier to develop and brings you all the power of Object Oriented programming with classes, inheritance and more.

July 30, 2010 -- Titanium Developer: love and hate (3)
June 14, 2011 -- Titanium Studio and Titanium Mobile 1.7 (0)
August 18, 2010 -- Titanium Developer: love and hate (Part II) (0)
September 21, 2010 -- Date from ISO 8601 string (1)

More WebSockets, now with Python!

Eneko Alonso — Sun, 23 May 2010 06:41:27 +0000

A couple of weeks ago, Tim and I worked on a little game/demo using WebSockets and C# (I haven’t been able to put it online since I do not have a Windows server). It was a lot of fun and we were able to see the potential of WebSockets and how much internet ~~can~~ will change in the next few years because of them.

Today I spent a couple of hours researching and implementing a WebSocket solution that I could run in my linux servers, and I found this very nice tutorial for creating a Python WebSockets server: http://yz.mit.edu/wp/web-sockets-tutorial-with-simple-python-server/

So I took that code and modified to create a very, very basic chat, that broadcasts received messages to all connected clients. You can try it here (as long as the python server is still up): http://enekoalonso.com/research/html5/websockets/python/

Here is the client code:

var form = document.getElementById('form');
var msg = document.getElementById('msg');
var output = document.getElementById('serveroutput');
var s = new WebSocket("ws://"+window.location.hostname+":9876/");
s.onopen = function(e) {
console.log("opened");
out('Connected.');
}
s.onclose = function(e) {
console.log("closed");
out('Connection closed.');
}
s.onmessage = function(e) {
console.log("got: " + e.data);
out(e.data);
}
form.onsubmit = function(e) {
e.preventDefault();
msg.value = '';
window.scrollTop = window.scrollHeight;
}
function sendMsg() {
s.send(msg.value);
}
function out(text) {
var el = document.createElement('p');
el.innerHTML = text;
output.appendChild(el);
}
msg.focus();

And the server code:

#!/usr/bin/env python
import socket, threading
# httphost = "localhost:8888"
# sockethost = "localhost:9876"
httphost = "enekoalonso.com"
sockethost = "enekoalonso.com:9876"
def handle(s, addr):
handsake = "HTTP/1.1 101 Web Socket Protocol Handshake\r\nUpgrade: WebSocket\r\nConnection: Upgrade\r\nWebSocket-Origin: http://%s\r\nWebSocket-Location: ws://%s/\r\nWebSocket-Protocol: sample\r\n\r\n" % (httphost, sockethost)
s.send(handsake)
data = s.recv(1024)
lock = threading.Lock()
while 1:
data = s.recv(1024)
if not data: break
print 'Data from', addr, ':', data
lock.acquire()
[conn.send(data) for conn in clients]
lock.release()
print 'Client closed:', addr
lock.acquire()
clients.remove(s)
lock.release()
s.close()
def start_server():
s = socket.socket()
s.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
s.bind(('', 9876))
s.listen(1)
while 1:
conn, addr = s.accept()
print 'Connected by', addr
clients.append(conn)
threading.Thread(target = handle, args = (conn,addr)).start()
clients = []
start_server()

Check the live demo (be aware WebSockets are only supported by Google Chrome right now): http://enekoalonso.com/research/html5/websockets/python/
Open a few tabs and send some text. You should see it appearing in all of them. It will also work if you open the page in multiple browser windows or even if you open the page in different computers.

May 3, 2010 -- Playing with WebSockets (4)
May 6, 2010 -- Tech talks at LEVEL Studios (0)
February 19, 2010 -- Having fun with Mooml & Twitter (0)
May 18, 2011 -- location.hash is dead (on html5 browsers) (0)

Playing with WebSockets

Eneko Alonso — Tue, 04 May 2010 04:20:37 +0000

Today I spent some time with Tim at work, playing with WebSockets, a new HTML5 feature that only Google Chrome supports so far. WebSockets allow browsers to create and maintain open direct TCP connections to the server, allowing instant communication in both directions. This means that ajax polling is no longer needed to get updates from the server. Instead, the server can send a message directly to the browser at any point in time while the connection is open. Awesome!

Since we are currently working on a C# .Net project, we searched Internet and found this very cool example that we took as a base for a little multiuser game we were working on today: WebSocket Chat

The potential of WebSockets is incredible, specially for online games and multiuser applications.

May 22, 2010 -- More WebSockets, now with Python! (9)
May 12, 2011 -- Angry Birds as a Web App (0)
June 8, 2010 -- Change in WebSockets handshake protocol (0)
May 6, 2010 -- Tech talks at LEVEL Studios (0)

Got NFS working

Eneko Alonso — Sun, 07 Feb 2010 06:19:27 +0000

Well, last night I started reading about how to share the files folder of a Drupal installation on a site with multiple web servers. Seems like NFS is the right way to go (as long as your traffic doesn’t grow too much). Perfect for Spaniards.es, since I want to move from a 2 dedicated server setup to a more flexible one where I can launch new web servers easily, almost on demand.

# Install NFS
yum -y install rpcbind nfs-utils nfs-utils-lib system-config-nfs rsync
# chkconfig nfs on
/sbin/chkconfig nfs on
vi /etc/idmapd.conf
# [General]
# Domain = spaniards.es
# [Mapping]
# Nobody-User = nfsnobody
# Nobody-Group = nfsnobody
service rpcidmapd restart
echo "/files/archivos /nfs4exports/archivos none bind 0 0" >> /etc/fstab
mount /nfs4exports/archivos
echo "/nfs4exports XXX.177.133.25(rw,insecure,no_subtree_check,nohide,fsid=0) XXX.177.136.14(rw,insecure,no_subtree_check,nohide,fsid=0)" > /etc/exports
echo "/nfs4exports/archivos XXX.177.133.25(rw,insecure,no_subtree_check,nohide) XXX.177.136.14(rw,insecure,no_subtree_check,nohide)" >> /etc/exports
su -c "/usr/sbin/exportfs -rva"
/sbin/service nfs restart
echo 'portmap:ALL' > /etc/hosts.deny
echo 'lockd:ALL' >> /etc/hosts.deny
echo 'mountd:ALL' >> /etc/hosts.deny
echo 'rquotad:ALL' >> /etc/hosts.deny
echo 'statd:ALL' >> /etc/hosts.deny
echo 'portmap:XXX.177.133.25,XXX.177.136.14' > /etc/hosts.allow
echo 'lockd:XXX.177.133.25,XXX.177.136.14' >> /etc/hosts.allow
echo 'mountd:XXX.177.133.25,XXX.177.136.14' >> /etc/hosts.allow
echo 'rquotad:XXX.177.133.25,XXX.177.136.14' >> /etc/hosts.allow
echo 'statd:XXX.177.133.25,XXX.177.136.14' >> /etc/hosts.allow
echo 'LOCKD_TCPPORT=48620' >> /etc/sysconfig/nfs
echo 'LOCKD_UDPPORT=48620' >> /etc/sysconfig/nfs
echo 'MOUNTD_PORT=48621' >> /etc/sysconfig/nfs
echo 'STATD_PORT=48622' >> /etc/sysconfig/nfs
echo 'RQUOTAD=no' >> /etc/sysconfig/nfs
echo 'RQUOTAD_PORT=48623' >> /etc/sysconfig/nfs

At the end, setting up NFS is not that complicated, but it was my first time, so it took a while. Actually, I had everything working before I noticed, since, logged in as root, I couldn’t figure out why I wasn’t able to write to the nfs mounted directory, being this mounted as rw. Well, turns out that you shouldn’t do this as root, since root access on nfs, once enabled does not require authentication.

I’m not sure why there is a need to mount a bind directory on the nfs server, but I think it has to do with the NFS4 directory configuration.

I think I got all the information I needed between these two links:
http://fconfig.wordpress.com/2006/08/17/setting-up-a-fedora-nfs-server/
http://fedorasolved.org/Members/renich/howtos/f7/en/nfsv4-fedora/?searchterm=nfs

Next step: set up the round robin load balancer: haproxy or dns?

January 31, 2010 -- CloudServers: Creating a new web server with httpd, php & memcached (1)
January 31, 2010 -- CloudServers: Creating a new MySQL db server (0)
January 30, 2010 -- Got new servers on Rackspace Cloud (5)
May 12, 2011 -- Angry Birds as a Web App (0)

CloudServers: Creating a new MySQL db server

Eneko Alonso — Mon, 01 Feb 2010 05:29:46 +0000

On my previous post I posted the commands I used to create a brand new Linux web server for my Drupal site. Now I’ll post the commands to create the database server. While creating the server instance at RackspaceCloud, I’ve chosen Fedora 12 for my db server, which comes with MySQL 5.1.42.

# Install MySQL
yum -y install mysql mysql-server rsync
/sbin/chkconfig –levels 235 mysqld on
# Start DB
/etc/init.d/mysqld start
# Grant permissions to db_user (1.2.3.4 is the web server IP address)
mysql -e "grant all privileges on db_name.* to db_user@'1.2.3.4' identified by 'password';"
mysql -e "flush privileges;"
#############################################################
# FIREWALL
# Open DB port 3306
# Allow connections only from web server
iptables -F
iptables -A INPUT -p tcp –dport 22 -j ACCEPT
iptables -P INPUT DROP
iptables -P FORWARD DROP
iptables -P OUTPUT ACCEPT
iptables -A INPUT -i lo -j ACCEPT
iptables -A INPUT -m state –state ESTABLISHED,RELATED -j ACCEPT
iptables -A INPUT -s 1.2.3.4 -p tcp –dport 3306 -j ACCEPT
iptables -L -v
service iptables save

As easy as that, having a MySQL server up and running is piece of cake :)

January 31, 2010 -- CloudServers: Creating a new web server with httpd, php & memcached (1)
January 30, 2010 -- Got new servers on Rackspace Cloud (5)
February 6, 2010 -- Got NFS working (0)
October 1, 2010 -- Having fun with node.js & Redis (1)

CloudServers: Creating a new web server with httpd, php & memcached

Eneko Alonso — Sun, 31 Jan 2010 17:16:47 +0000

Creating a new web server is piece of cake at Rackspace Cloud. Here is a demo video of how to set up a new instance with your favorite Linux distribution. I have used Fedora 12 for my new spaniards.es servers, and here is the script I’ve used to install everything needed so far:

# Install HTTPD
yum -y install httpd rsync
# Install PHP
yum -y install php php-mbstring php-mysql mysql
#############################################################
# FIREWALL
# Open http port 80 (and ssh)
iptables -F
iptables -A INPUT -p tcp –dport 22 -j ACCEPT
iptables -P INPUT DROP
iptables -P FORWARD DROP
iptables -P OUTPUT ACCEPT
iptables -A INPUT -i lo -j ACCEPT
iptables -A INPUT -m state –state ESTABLISHED,RELATED -j ACCEPT
iptables -A INPUT -p tcp –dport 80 -j ACCEPT
iptables -L -v
service iptables save
# Start HTTPD server
/etc/init.d/httpd start
# Install memcached
yum -y install memcached
memcached -d -u apache
yum -y install php-pecl-memcache
# Restart HTTPD server
/etc/init.d/httpd restart

DNS configuration can be done through the admin pages, so there is no need for manual configuration. Copying the data from your old server can be done with rsync and having mysql installed is handy to test db connections from the console.

In less than 10 minutes you can have a new web server up and running :)

January 31, 2010 -- CloudServers: Creating a new MySQL db server (0)
January 30, 2010 -- Got new servers on Rackspace Cloud (5)
February 6, 2010 -- Got NFS working (0)
December 5, 2008 -- Enabling PHP5 on Mac OS X Leopard (0)

Got new servers on Rackspace Cloud

Eneko Alonso — Sun, 31 Jan 2010 01:06:09 +0000

Last night I got an account at Rackspace Cloud and created three brand new CentOS Linux servers. Now I have to set them up: two web servers and one database server. My goal: Move Spaniards.es website to this new hosting.

Why move?

Currently I am hosting Spaniards.es on two dedicated servers at Ace-Host.net. So far, so good, but the site has started to get slow (more the web server than the db server, which is running great so far). Some days I found the site running at 30 times the processor capacity (according to ‘top’), which is a lot. The biggest problem I have right now is the caching on the web server. I have installed both XCache and Memcached, but can get them to work since that server was my first ever dedicated server an has a CPanel installation that drives me nuts.

Sooner or later I had to move that webserver into a new clean installation, but I have decided that if I have to move, I’ll do it to a cloud. No more dependencies on a physical hardware, no more worries.

Why not EC2

Well, I’ve ried EC2 and it is not that I don’t like it. It is just that it is so much work. After seeing how CloudServers work on RackSpace, I have no doubt.

When is Spaniards.es going to be moved?

There is no date yet. First I have to set up the servers, make sure everything works fine, set up the domains, dns, mail, etc. Hopefully in a couple of weeks, if I can find enough time to do so.

January 31, 2010 -- CloudServers: Creating a new web server with httpd, php & memcached (1)
January 31, 2010 -- CloudServers: Creating a new MySQL db server (0)
February 6, 2010 -- Got NFS working (0)
October 1, 2010 -- Having fun with node.js & Redis (1)

Check your server status with email notification

Eneko Alonso — Sat, 03 Jan 2009 19:34:11 +0000

I wanted to do this for a while and never really sit down and code it. Yesterday I came across this pretty nice script by Ben from Coderholic which does exactly that: check your server status and send you an email if it is other than 200 (OK).

#!/bin/bash
# Query a supplied URL and output an error message if
# the status code was not 200. Can be used as a cron
# task to check if a server is up or not.
# Ben Dowling – http://www.coderholic.com
# The URL to query
if [ $# -ne 1 ]
then
echo "Usage: $0 ";
exit;
fi
url=$1;
response=$(curl -s -I -L $url | grep HTTP);
status=${response#* }; # Strip off characters up to the first space
status=${status:0:3}; # Just use the 3 digit status code
if [ "$status" != "200" ]
then
echo "Error fetching $url. Status code '$status'";
fi

Nice.

July 13, 2011 -- Clone your OSX terminal window (1)
October 12, 2011 -- Command line scripting with Node.js (0)
August 6, 2011 -- Python script: remove empty folders (1)
October 1, 2010 -- Having fun with node.js & Redis (1)

dev.enekoalonso.com » server

Having fun with node.js & Redis

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