Comparison of Software Configuration Management Tools

Size: px

Start display at page:

Download "Comparison of Software Configuration Management Tools"

Earl Miles
6 years ago
Views:

1 e-issn Volume 2 Issue 9, September 2016 pp Scientific Journal Impact Factor : Comparison of Software Configuration Management Tools Aishwarya Nair 1, Meenakshi Dhanani 2, Rupesh Gangwani 3, Prof. Hema Gaikwad 4 1,2,3 Student, 4 Asst.Professor 1,2,3,4 SICSR Abstract Software Configuration Management also known as revision control is any kind of practice that tracks and provides control over changes to source code. It is used widely to manage large scale projects having greater number of collaborators. Well known version control tools like Git, SVN (Subversion) and Mercurial are audited in this paper which helps in overseeing and following changes to an application during its development. I. INTRODUCTION Software or an application is comprised of various physical elements. These elements include requirement documents, source codes, test cases, reports, test scripts, third party software and the likes. Over the span of making the product, arrangement of surveys and gatherings happen and these entities change frequently. Since each of these elements, is entirely intricate and dynamic in nature, it is critical to oversee and have control on these progressions [1]. This is where configuration management tools or version control tools come into picture. Changes are typically recognized by a number or letter code, termed the "revision number", "revision level", or simply "revision". For instance, an initial set of files is "revision 1". At the point when the main change is made, the subsequent set is "revision 2" and so on. Every modification is connected with a timestamp and the individual rolling out the improvement. Revisions can be compared, restored, and sometimes even merged. The requirement for a sensible approach to arrange and control revisions has existed for as long as writing has existed, however version control turned out to be significantly more vital, and muddled, when the era of computing began. The numbering of book editions and of specification revisions are examples that date back to the print-only era. Today, the most capable (as well as complex) revision control systems are those used in software development, where a team of people may change the same files. Version control systems (VCS) most commonly run as stand-alone applications, but revision control is also embedded in different sorts of software, such as word processors and spreadsheets, collaborative web docs and in various content management systems (CMS), for instance Wikipedia's Page history. Revision control allows for the ability to revert a document to a previous revision, which is basic for permitting editors to track each other's alters, right missteps, and safeguard against vandalism and spamming. Software tools for revision control are vital for the association of multi-developer ventures. This paper gives a brief thought regarding which version control tool is most appropriate to a venture's needs, a comparison between popular version control tools, their pros and cons, and a rundown of their components which makes it more favoured over its rivals. II. SCM TOOLS Open source distributed revision control systems with important features of forking, merging, push (commit changes), pull requests etc. are available. However, each of them is preferred over the other for specific reasons. This section summarizes the capabilities and highlights of revision control systems, viz. Mercurial, Git, All rights Reserved 40

2 Operations in Revision Control Systems [4] A) Mercurial Mercurial is easy and fast revision control tool to manage projects of any size. It supports a lot of workflows and can be enhanced via extensions. Mercurial CLI is designed to be very simple with easy understanding of all options. hg help can also be used to find out about various ways of working with the tool. It focuses on clarity as compared to cleverness. Thus it is simple to use. Mercurial helps to maintain all old versions of the code, using Mercurial's hg rollback. The last pull or commit is rolled back. Extensions are available that let us rewrite history. Mercurial is considered the best on a Windows machine. It can also be built from the source on a Windows machine, without relying on already packaged binaries. Mercurial has a lot of extensions that make it easy to customize it, and thus scale it [2]. Commands for daily use in mercurial: hg init hg status hg add hg All rights Reserved 41

3 For example, $ hg init demo $ cd demo $ echo demo > mydemo.txt? mydemo.txt $ hg add mydemo.txt A mydemo.txt $ hg commit -m 'Added one file' In the above example, Mercurial tracks files and not directories by the hg add command. Once added the status changes from "?" to "A". After commit and hg status, Mercurial will only tell about files that have been changed/renamed etc. Thus no files are returned. To stop tracking a file, we use: $ hg remove mydemo.txt R mydemo.txt Thus, Mercurial is very easy to use and a lot of tools or IDEs allow Mercurial. Importing a project from another version control system to Mercurial is also easy. [3] B) Git Git is a distributed revision control and source code management system with an emphasis on speed. Git was initially designed and developed by Linus Torvalds for Linux kernel development. It specifically works by taking snapshots of files; if records stay unaltered in a specific adaptation, it simply links to the previous files this keeps everything fast and lean. [4] With a distributed version control system, there isn t one centralized code base to pull the code from. Different branches hold different parts of the code. Other version control systems, such as SVN and CVS, use centralized version control, meaning that only one master copy of the software is used. Git prides itself on being a quick and proficient framework, and numerous significant open-source ventures use Git to control their repositories; projects like Linux Kernel, WINE, Fedora and many others. Regularly individuals get confounded thinking Git and Github are one and the same; however there exists real contrasts amongst them. In spite of the fact that you can run your own particular Git server locally, Github is a remote server, a group of designers, and a graphical web interface for dealing with your Git project. It s free to use for up to 5 public repositories. [5] GitHub has as of late settled Git as a great version control system, giving a wonderful front end to numerous substantial projects, for example, Rails and Prototype. [6] Git basic terminologies: Trees: Tree is an object, which represents a directory. It holds blobs and additionally other sub-directories. Commits: Commit holds the current state of the repository. From a given commit, you can traverse back by looking at the parent pointer to view the history of the commit. If a All rights Reserved 42

4 has multiple parent commits, then that particular commit has been created by merging two branches. Branches: Branches are utilized to make a different line of development. More often than not, a branch is created to work on a new feature. Once the feature is finished, it is converged back with the master branch and we delete the branch. Clone: Clone operation creates the instance of the repository. It not only checks out the working copy, but also mirrors the complete repository. Pull: Pull operation copies the changes from a remote repository instance to a local repository instance. The pull operation is utilized in synchronization of two repository instances. Push: Push operation copies changes from a local repository instance to a remote repository instance. This is used to store the changes permanently into the Git repository. Revision: Revision represents the version of the source code. Revisions in Git are represented by commits. Example: $ git init $ git add demo.txt $ git status $ git commit -m "My Demo Project" $ git log $ git remote add origin $ git push -u origin master $ git pull origin master $ git branch clean_up $ git checkout master $ git merge clean_up $ git branch -d clean_up $ git push In the above example, we are creating a repository and initializing it with a demo.txt file and checking the logs, status of changes. Also we can commit these changes to github, create a branch, clean the branch, merge it and push the final changes to the repository. Other collaborators can pull from this repository and push their own changes. It is a lot of commands as compared to Mercurial and that is the main reason Git is not recommended for use for beginners as it is difficult to grasp the commands for different operations. But Github has made it easy by providing a Web interface for managing Git repositories even on operating systems which do not support command line operations. C.) SVN Apache Subversion (an open source version control system, aka SVN, after the command name svn) is a software versioning and revision control system. It is widely used by developers to maintain current and previous versions of files such as source code, web pages, and documentation. The goal of SVN is to be a most compatible successor to the widely used tool Concurrent Versions System (CVS). Subversion was developed by CollabNet Inc. in 2000, and is now a top-level Apache project being developed and used by a global community of open source All rights Reserved 43

5 Subversion s Components: International Journal of Current Trends in Engineering & Research (IJCTER) SVN has many components; some of the important ones are as follows: svn: The command line client executable program. svnversion: A program which enables reporting the state (in terms of revisions of the items present) of a working copy. svnlook: It is a tool to look up a Subversion repository. svnadmin: A tool for setting up, tweaking or repairing a Subversion repository. svndumpfilter: A program to filter repository dump streams of Subversion. mod_dav_svn: It is a plug-in module for the Apache HTTP Server, enables the repository to be accessible by other users over a network. svnserve: Another tool to enable the repository to be accessed by other users over a network. It runs as a daemon process or is invoked by SSH. SVN Architecture: Subversion s Architecture All rights Reserved 44

6 Subversion s Repository Types: 1. Berkeley DB: The initial development of Subversion used the Berkeley DB package. The features of Subversion were limited when used with Berkeley DB, when the database is accessed by a program, crashes or terminates forcibly, no loss of data or corruption occurs, but the repository stays offline while Berkeley DB replays the journal and cleans up any pending locks. In that case, using Subversion with a Berkeley DB repository with a single server-process running as one user (instead of through a shared file system) was the most secured/safe way. 2. FSFS: FSFS was developed in 2004, as a new storage subsystem. It performs better than the Berkeley DB backend on directories with a huge count of files and occupies less disk space, due to less logging. [8] Starting from Subversion 1.2, FSFS was declared as the default data store for new repositories. The etymology of "FSFS" is based on the term file system used in Subversion for its repository storage system. FSFS stores its contents directly within the operating system's file system, rather than a structured system like Berkeley DB. Thus, it is a File System [Subversion] on top of the File System". III. COMPARISON OF MERCURIAL, GIT, SVN Following table illustrates the differences between revision control and SCM tools based on certain factors or features. Features Mercurial Git SVN Easy to use for beginners Yes No Yes Preferred on Windows Yes No Yes Distributed Repository Model Yes Yes No Keyword Expansion Yes No Yes Lock No No Yes Rollback Yes Yes No Server needed No No Yes Signed revisions Yes Yes No Timestamp Preservation Yes No Yes Command aliases Yes Yes No IV. CONCLUSION With its wide range of usage and its software maturity level, SVN has a large knowledge base, and users will be able to find help readily accessible from other users. It has a clear speed improvement over its competitors, and for projects that lend themselves to distributed systems, it is a clear improvement. The primary downside cited for Git is that it can be at times difficult to explain to others, and there is likely to be a slowdown in production as programmers adapt to it. Once it is learned, however, the speed increases and better branch management will reclaim that time All rights Reserved 45

7 more. For those absolutely repulsed by Git, Mercurial offers a bridge between SVN and Git that is well documented and used in many well-known projects. To find out which one is best for you, consider the project and the developers. And talk to them! If you want to have a single master source tree that is being worked on by a small core development group, SVN should be the first system you try as it s reliable and tailored for that. If you are starting an open source project where several programmers are going to be working at different times and/or submitting several updates to the code, Git is an excellent choice for your project due to the huge speed boost and improved tree management over SVN. If you re somewhere in the middle or you just really don t like the way SVN or Git works for you after trying them, there s always Mercurial. [9] REFERENCES [1] Top 5 Software Configuration Tools - Retrieved from: [2] Mercurial: The Definitive Guide by Bryan O'Sullivan [3] Giancarlo Lionetti(2012, February 23) Re: Mercurial vs Git: Why Mercurial? [Web log]retrieved from: [4] Git Lifecycle - Retrieved from : [5] [6] [7] Collins-Sussman, Ben; Brian W. Fitzpatrick; C. Michael Pilato (2011). "What is Subversion? > Subversion's History".Version Control with Subversion (for Subversion 1.7). Retrieved 15 March [8] Ben Collins-Sussman; Brian W. Fitzpatrick; C. Michael Pilato (2011). "Chapter 5: Strategies for Repository Deployment".Version Control with Subversion: For Subversion 1.7. O'Reilly. [9] All rights Reserved 46

2/9/2013 LAB OUTLINE INTRODUCTION TO VCS WHY VERSION CONTROL SYSTEM(VCS)? II SENG 371 SOFTWARE EVOLUTION VERSION CONTROL SYSTEMS

2/9/2013 LAB OUTLINE INTRODUCTION TO VCS WHY VERSION CONTROL SYSTEM(VCS)? II SENG 371 SOFTWARE EVOLUTION VERSION CONTROL SYSTEMS SENG 371 SOFTWARE EVOLUTION LAB OUTLINE Introduction to Version Control Systems VERSION CONTROL SYSTEMS Subversion Git and Github 1 Prepared by Pratik Jain 2 INTRODUCTION TO VCS A version control system