Xzajo's Weblog

Thursday June 22, 2006

P2P programming

Few years ago has been introduced XP programming. A part of XP programming was pair programming. What is pair programming? Two developers are programming together on one computer. They are reviewing their ideas in one time. It rapidly increased quality of code.

Pair and XP programming is applicable to small teams. It is quite difficult to use XP methods on project where are for example hundreds developers. What is missing here? The developers didn't provide inter team communication about their codes. It is really difficult to share knowledge among all the developers.

Another way how to review the code is send commit logs to public mailing list. The commit logs are read only inside small team because it is not effective if the developers checks commit logs from many developers.

An inspiration how to solve this problem can be P2P data sharing. P2P data sharing was invented in order to reduce load of server. Big file is split to many small parts. Different parts are distributed to different users(nodes). If the node download his part he can redistribute the parts to different users. For each node in P2P network is computed ration uploaded/downloaded. When the ratio is very small the node got smaller priority for downloading files than node with bigger priority.

We can map P2P networking problem to code review problem. A node is developer. A developer commits code.Other developers reviews his code. It is the same like P2P network. The download is reviewing his code. The upload is reviewing of other's developer code. If the developers doesn't review code. No one is interested in review his code because the commit log is on the end of list with commits for code review.

The commits log are sent to different groups of developers. How to distinguish the developers? There are few metrics: -A developer uses a API. The API owner is in commit logs. The api usage is in commit log of the the user. The owner of API do the review. -He uses the API for long time I got many reviews. He is experienced API user. He can do review of code which uses the API or do the review to API developer Sent the same count of commit logs to different developers.

The reviewer must mark the reviewed code:

• The code is good
• The code is wrong

He can also add comments to review.

For the code review can be created a plugin to IDE.

The P2P programming can be used for code evaluation between different projects if they uses the same API or export API. For example first group develops WEB framework. The second group develops web application. The second group uses the framework of the first group. The first group do review of the code of the second group. After a while third group of developers started use the API of the first group. The code of third group will can review second group because they are experiences users of the framework.

Please let me know if already exists software project similar to P2P programming.