Do you sometimes need to run a test or experiment hundreds to thousand times for obtaining more data points in your graph? Do you also feel like being a monkey when pressing the enter button on a keyboard every 5 minutes for conducting the experiment? It should be easy to automate such an experiment when it is performed on a single computer. However, if your measurement points are spread in different computers or even in different networks, any link or node delays will ruin your experiments. Meaning that you have to stay in front of the computer(s) and press the enter button every 5 minutes until the entire experiment is done.
This simple program will automate your experiment in a networking environment. This program consists of the two ruby scripts, namely, Controller and Controllee. The Controller is, as the name suggests, the master process that gives orders to Controllees, for example, to start an experiment or to wait for other machines to finish their job. In this way, the machines will work alone and you can spend your time on a more useful stuff. How does it sound?
Ok, to give you more insight about these scripts, here's my experiment setup when I used them:
+----------+
|Controller|
+-----+----+
|
+----------------+------+------+---------------+
| | | |
| | | |
| | | |
+-+-+ +-+-+ +-+-+ +-+-+
|EE1+------------+EE2+---------+EE3+-----------+EE4|
+---+ +---+ +---+ +---+
I had to record network packets that are generated from EE1 and forwarded to EE4 via EE2 and EE3. The same packet had to be recorded on every nodes (EE1 ~ EE4). Normally in such a setup, when one of these machines experiences a delay, all subsequent experiments will be out of their joint work. So, by using this program, Controllees send the status message to the Controller on every experiment steps. The Controller can orchestrate the experiment based on the status sent by Controllees. For example, Controllees will only start an experiment when the Controller gives them an order to start it.
These scripts are simple and easy to read, so modify them as you want and help youself to escape from the experiment slavery. ;) A step-by-step instruction may be added in this document in the future.