Malaysia Open Source Community Meetup Quarter 4 2015 (MOSCMY Q4 2015)
By Muhammad Najmi bin Ahmad Zabidi
December 9, 2016
After a year, finally I decided to publish this post to all of you!
On November 26th 2015 I had a chance to give a talk in a local open source conference here in Malaysia. The organizer requested me to specifically deliver a talk on “remote work”. This meetup was organized by Malaysian Development Corporation (MDEC) with the sponsorship of Microsoft Malaysia. Microsoft recently started to become more “open source friendly” given that they are in the effort of pushing their cloud based product, Azure. The full schedule of the event can be referred here.
The conference was divided into two sessions; where the morning session was held in Petronas Club, Tower One of Kuala Lumpur City Centre (KLCC) and the other session was held in Microsoft Malaysia’s office in Tower Two KLCC. Generally the morning session was for non parallel track (including my track) and the afternoon sessions were two parallel sessions slot.
Morning Session
The morning session started with a talk by Dinesh Nair, as the Director of Developer Experience and Evangelism, Microsoft Malaysia. The second session in the morning was delivered by Mr Izzat M. Salihuddin, from Multimedia Development Corporation (MDeC), …
community open-source
Postgres statistics and the pain of analyze
By Greg Sabino Mullane
December 7, 2016
Anytime you run a query in Postgres, it needs to compile your SQL into a lower-level plan explaining how exactly to retrieve the data. The more it knows about the tables involved, the smarter the planner can be. To get that information, it gathers statistics about the tables and stores them, predictably enough, in the system table known as pg_statistic. The SQL command ANALYZE is responsible for populating that table. It can be done per-cluster, per-database, per-table, or even per-column. One major pain about analyze is that every table must be analyzed after a major upgrade. Whether you upgrade via pg_dump, pg_upgrade, Bucardo, or some other means, the pg_statistic table is not copied over and the database starts as a clean slate. Running ANALYZE is thus the first important post-upgrade step.
Unfortunately, analyze can be painfully slow. Slow enough that the default analyze methods sometimes take longer that the entire rest of the upgrade! Although this article will focus on the pg_upgrade program in its examples, the lessons may be applied to any upgrade method. The short version of the lessons is: run vacuumdb in parallel, control the stages …
postgres
Implementation of Ruby on Rails 5 Action Cable with Chat Application
By Selvakumar Arumugam
December 3, 2016
Ruby on Rails is a wonderful framework for web development. It was lacking for one important feature since the world has been moving to towards realtime data. Everyone wants to see the realtime data on the applications. Mostly, real-time web applications are now accomplished using WebSocket.
WebSocket provides full-duplex communication between server and client using TCP connection once the handshake completed through HTTP protocol. WebSocket transfers streams of messages on top TCP without being solicited by the client which boosts the data transfer performance on high level compare to HTTP request/response.
WebSocket were adopted on RoR applications with help of third party libraries. But Rails 5 came up with a module called ActionCable which is seamlessly sits with existing framework and integrates the WebSocket to the application. ActionCable provides server and client side framework to implement WebSocket with the application.
ActionCable Overview:
Server Side:
Connection: The Connection only handles authentication and authorisation part of logic. The connection object is instantiated when request from the user comes through browser tab or window or devices. Multiple …
rails javascript
Perl Dancer Conference 2016 Day 1
By Sam Batschelet
November 30, 2016
Perl Dancer Conference Day 1
The Perl Dancer Conference is a great event, now in its third year. 
The event took place in the same location as last year in Vienna, Austria at the Hotel Schani Wien. For those of you who have never visited Vienna, it is a perfect place to bring the family. From visiting the beautiful parks to taking a scenic ride on the Danube River, the beautiful and historic city is known for its rich art and musical culture, and has much to offer.
I was very excited to not only attend but also give a talk this year. My talk titled “Dancing in the Clouds” also coincided with the release of 2 new Perl modules Etcd3 and Dancer2::Plugin::Etcd. This article will be the first of a 3 part series, with the final article a focus on my talk and usage examples with the new modules.
Sawyer X (Sawyer X) — A bus tour through Dancer core
The Captain of Dancer core, SawyerX, took us on a bus tour through the core functionality of Dancer2. Using practical examples of code blocks from core, he explained how different areas of the code base worked. I personally enjoyed his explanation of how hooks are implemented and created. Learning from the 1st iteration of Dancer, the second …
conference perl devops
Throw It Away: Suppressing Writes on PostgreSQL Replicas
By Josh Williams
November 30, 2016
We needed a way to suppress specific write commands on a Postgres streaming replica. The replica was set up for a DR configuration, with the applications able to be brought up into full service at a moment’s notice. But since it’s a hot standby, we’d like to still allow the applications to be used in a working but read-only state.
One of the applications on this database is MediaWiki, which worked great in this configuration. But a couple of the other apps have the classic behavior of updating its user object’s “last login” field in one form or another when someone authenticates, which would cause the login process to fail entirely.
Of course we want updates to fail, up until that point when (knock on wood) the master server is declared down for the count and the official fail-over happens. Except for the one command that executes on login.
We don’t really care about the “last login” type field – the data is available through logs and other means. The affected apps could probably all be monkey patched to work around that part of the process. But we had a couple different apps doing this, and that adds a maintenance burden for each. And if we could figure out how to make it …
postgres replication
Vim Golf: Learning New Skills for Code Editors
By Josh Lavin
November 28, 2016
Vim is a text-based editor that has been around for 25 years. It comes pre-installed on Linux distributions, so it is a great tool for developing on servers. One of the advantages of Vim is that oft-used keystrokes can be performed without moving your hands from the keyboard (there is no mouse in Vim).
Many of the engineers here at End Point use Vim for our daily development work, and recently, a few of us got together online to try to learn some new tricks and tips from each other. Being efficient with Vim not only improves productivity, it’s a lot of fun.
Similar to playing a round of golf, we tested each other with various editing tasks, to see who could perform the task in the fewest number of keystrokes. This is known as “Vim Golf.” There is even an entire website devoted to this.
In this post, we share some of the interesting tricks that were shown, and also some links to further learning about Vim.
Tips & Tricks
- Indenting text: there are multiple ways to do this, but a few are:
- Visually-select the lines of text to indent (Ctrl v or Shift v), then > to indent, or < to outdent. Press . to perform this action again and …
vim
Connect Multiple JPA repositories using Static and Dynamic Methods
By Selvakumar Arumugam
November 16, 2016
The JPA Repository is a useful Spring Framework library that provides object-relational mapping for Java web applications to be able to connect to a wide variety of databases. Most applications need to establish a connection with one database to store and retrieve the data though sometimes there could be more than one database to read and write. There could also be some cases where the application needs to choose which database should be used dynamically, based on each request’s parameters. Let’s see how to configure and establish connections for these three cases.
1. Single Static Connection
In order to use JPA the following configurations are required to get the database connection handle and define the interface to map a database table by extending JpaRepository class.
UserRepository.java — this part of the code configures how to map the user table
package com.domain.data;
import com.domain.User;
import org.springframework.data.jpa.repository.JpaRepository;
public interface UserRepository extends JpaRepository <User, Integer> {
}persistent-context.xml — the dataSourceReadWrite bean class defines the database connection while the entityManagerFactoryReadWrite bean helps …
database java
DNS and BIND Training with MyNIC
By Muhammad Najmi bin Ahmad Zabidi
November 16, 2016
This is yet another yesteryear’s story!
I had a chance to attend a DNS/BIND training which was organized by Malaysia’s domain registry (MyNIC). The training took two days and was organized in Bangi, Selangor, Malaysia. Dated November 23 to 24, 2015, the two days’ training was packed with technical training for the Domain Name System (DNS) using BIND software. Our trainer was Mr Amir Haris, who is running his own DNS specialist company named Localhost Sendirian Berhad (Sendirian Berhad is equivalent to “Private Limited”).
Day One
For Day One, the trainer, Mr Amir Haris taught us on the theoretical details of the DNS. For a start, Mr Amir explained to us on the DNS operation, in which he explained the basic of what DNS is and the function of root servers. Later he explained further on the root servers’ functions and locations. It was the followed by the explanation of query process.
Mr Amir also explained to us the difference of DNS implementations across different operating system platforms. As for the training since we were using BIND as the name server’s software, we we exposed to the historical background of BIND.
The concept of master and slave DNS server was also being taught. …
sysadmin