kyo504/diskusage

A program to leave log messages after checking the given physical disk periodically

Diskusage program

Contents

• Description
• Requirements
• Options
• Test Cases
• Development Log

Description

This program periodically writes a log message onto the given disk and the log message has a pre-defined format.

Requirements

• Program runs on linux environment
• Usage of disk is checked in every 1 minute
• Depending on the usage, the level of log is different
  • 0% ~ 89% : INFO
  • 90% ~ 94% : WARNING
  • 95% ~ : ERROR
• Program is written in Python
• The log format is like below
  • level:INFO path:/mnt/storage capacity:5% size:8989800

Options

There are three optional arguments and the description of each is described below:

• mounted: A path for mounted device or partition. For the invalid path, the program is terminated with error message. Default path is /
• logtype: stdout, file, syslog
• logpath: A file name with path. Only used in case that logtype is file

<a name="testcases"Test Cases

Test Environment Platform : OS X, Ubuntu 12.04LTS(32bit) Language : Python 3.4

1. Run program with default values

   • Options : default(mounted path= /, log type= stdout, log path= None)
   • Command

   $ python3.4 main.py

   • Expected result: log data displays via stdout

2. Run program with an argument which specifies invalid mounted position

   • Options: mounted path= /not/existing/path
   • Command

   $ python3.4 main.py --mounted=/not/existing/path

   • Expected Result: Program is terminated with error message

3. Run program with the some options#1

   • Options: mounted= /valid/mounted/position, log type= file, log path=/your/desired/path/filename
   • Command

   $ python3.4 main.py --mounted=/valid/mount/path --logtype=file --logpath=/your/desired/path/diskusage.log

   • Expected Result: Log data are stored in the specified path as text file

4. Run program with the some options#2

   • Options: mounted path= /valid/mounted/position, log type= syslog, log path= None
   • Command

   $ python3.4 main.py --mounted=/valid/mounted/position --logtype=syslog

   • Expected Result: Log data are stored as system log.

<a name="devlog"Development Log

From now, I could describe the basic approach to implement this program and how I dealt with some issues that I was faced with.

This program has 4 major features.

1. To parse incoming arguments via command line
2. To retrieve disk or partition information from the given mounted path
3. To write logs with pre-defined format
4. To set a timer to invoke callback periodically

Basically, I used modularization to simplify the main function as much as possible. Therefore #1, #2, and #3 were implemented as class separately, and the last one(#4) was a module only containing function.

During designing overall program structure, timer was the most difficult part. From my previous experience, I thought that SetInterval in Javasciprt is the best fit to achieve the goal but there was not a nice and neat way in python. Therefore I googled and found some possible solutions.

• Using threading
• Using sched
• Using Advanced python scheduler

Among those solutions above, I choosed the first one because I was a bit more familiar than others. And there were two ways to implement SetInterval with threading.

1. Decorator function with decorator arguments
2. Standalone function without decorator

Even though I implemented two functions, the fundamental concept of the two is the same.

• Call timer function with an interval value. ]
• Create a thread and run start-routine
• Wait for the given interval and if flag is not set run another loop
• Stop loop if the flag is set to true by calling set function