simplequeue

simplequeue is a simple queueing utility, which can read tasks from a text file. Everything that can be expressed as a single line in a plain-text file is a task.

Features

• queueing tasks inside .txt files
• separate client for adding tasks
• execution of success- and error-scripts after processing tasks
• growl notification
• simple extending of configuration using yml
• daemonizing of task processing
• assigning tasks priorities (0-9 are supported so far, default prio is 9)
• filter tasks and assign priorities according to task-name or current date

Dependencies

• configatron
• escape
• daemons

for running the unit tests, you'll also need fakefs

Usage

Configuration

To get started, copy the file config/config.yml.example to config/config.yml abd add the absolute path to your queue_dir. All the files necessary for queueing will be stored in this directory. Specify a queue_prefix if you want the queue files to start differently than queue.txt. Write the script for the task to be executed in scripts/process. The task will be given as a string as first parameter to the script. If you want you can add custom handling for success and error in scripts/success and scripts/error. To enable growl notification just ensure that the path to the growlnotify binary is set correctly in growlnotify_cli.

Adding Tasks

To add a task to the queue execute simplequeu.rb <taskname> -p<prio>. For adding multiple tasks, separate them by spaces (shell globs are supported - especially handy for adding filenames as tasks). The tasks will be added to a .txt file in queue_dir. The priority will be appended to this file.

For example: simplequeue "a simple task" -p7 adds the task "a simple task" to the file /opt/queue/queue.txt.7. The queue files with the highest priority (smalles number) will be executed first. When all the tasks in this file are executed, the next queue_file which has the next highest priority (next greater number) will be executed. Task executing will not be interrupted. If you add a prio 1 task, while a prio 9 task is executed, the prio 1 task is executed next.

Priority Filtering

Additionally you have the opportunity to assign a priority according to the task-name, current date (or incoming prio).

Just implement the method (task_name, prio, current_date) in the file task_filter.rb (plain ruby). If you add the tasks using the simplequeue.rb command-line tool, you'll get 3 parameters:

• task_name: (the name of the task to be added)
• prio: (the priority that has been set using the -p flag (-1 if no prio was set))
• current_date: the current date

The default behaviour is:

• return prio when set, return 9 when not set

Here's an example implementation of assigning priorities according to their name:

class TaskFilter

    def filter(task_name, prio, current_date); 
      search_hash = { "work" => 1, "fun" => 7, "something in between" => 3}
      prio_to_return = 9

      search_hash.each do |key, value|
        if task_name.downcase.include?(key.downcase)
          prio_to_return = value
          break;
        end
      end

      return prio_to_return
    end
end

Start Task Queue

To start queue process simply start simplequeue_daemon.rb. For daemonizing execute simplequeue_daemon_control.rb start.

Attribution

The icons I used for the growl notification I took from here: http://www.icojoy.com/articles/46/.