Log4r is a Ruby gem that features a heirachical logging system of any number of levels, custom level names, multiple output destinations per log event, custom formatting, and more. The Log4r gem is open sourced on GitHub, and with comphrehensive documentations available on Rubyforge.

I have been using log4r at work in most of the applications and systems written in Ruby. It’s easy to use, and provide the features that an application would need: - Support multiple message levels such as Fatal, Error, Warn and Msg.
- Customizable log file format - Multiple output destinations, like print out on the screen, and store in a log file

Here in this post, I’ll show you how to use log4r in your Ruby project.

大概从18个月前开始，我开始习惯使用Trello作为project management and tracking的主要工具，也逐渐体会到Trello的特点和便利之处。总结起来，“不得不使用Trello”的理由有下面一些：

本文内容部分来源于Andrew Bayer发布在SlideShare上的 7 habits of highly productive Jenkins Users (2014 Edition).

习惯 2: 大而化小

1. 使用多个Masters

在存在多个project与team的情况下，多个master可以使jenkins jobs的管理更加敏捷和可控

建议根据team, function, access(访问权限) 来划分master

多个master使安装和升级plugin时需要的重启过程变得容易——不需要重启的master不会受到影响

提高系统的稳定性：多个master, 每个master上分配较少数量的jobs，可以使整个系统更为稳定，减少遇到边界情况bug的几率

2. 分解jobs

建议在Jenkins中使用模块化和重用，这一点的好处类似于在编程中使用模块化和重用

多job的Build可以方便地在不同的project, release等等中重用

分解job可以避免长时间运行的job在最后阶段出错，导致整个job需要被重新运行：多job的Build可以实现从其中任何一个子job处重新执行

本文内容部分来源于Andrew Bayer发布在SlideShare上的 7 habits of highly productive Jenkins Users (2014 Edition).

习惯 1: 保持Jenkins Master的稳定与可恢复

1. 使用LTS Release

LTS release每12周发布一个新版本

LTS release版本发布都会保证通过自动化的acceptance testing和手工testing matrix

2.不要急于升级plugins，保持谨慎

plugin的升级可能包含非常多的变化

不是所有的升级都会保证向前兼容。比如最近Extended Email Plugin的升级，就造成之前的recipient/trigger配置不可用

新功能也许不稳定

The Element of Linux Screen

Linux Screen is a tool installed in Linux system with which you can manage multiple interactive shell processes. With Screen, you can have multiple shells in the same window. You can detach shell processes and attach them when you log into the system from other sessions. With Screen, you don’t need worry about losing your half-way tasks when the terminal exit. I use the Screen on a daily basis, and here I write down the commands and usages that are most commonly used in my everyday work.

Start Screen

In a system where screen is installed, type “screen” in a terminal will invoke it.

If screen isn’t installed in your system, Google “install screen in Linux” to find the solution.