Software Configuration Management

1
Software Configuration Management
2
Software Configuration Management

• What is it?
• Software Configuration Management is the process
  of tracking changes to software.
• Why use it?
• Maintain multiple branches and versions.
• Recover previous versions.
• Keep track of changes, ie, committed changes.
• When to use it?
• For text files programs, data, and configuration
  files.
• Supports binary files Word and Excel files,
  etc.
• In multi developer contexts can assign blame for
  changes.

3
Software Configuration Management

• Used in both single user and multi user
  environments.
• There are two multi user paradigms
• Locked access A single developer checks-out a
  copy of a file before modifying it. The modified
  file is then checked-in. During check-out only a
  single developer has access to the file.
• Concurrent access Multiple developers work with
  their own copy of a file. Conflicts are resolved
  as the local copies are committed to the common
  repository.

4
Software Configuration Management

• There are many implementations of version control
  software.
• RCS (Revision Control System) is one of the
  earliest. It was developed along with Unix. It
  is implemented as check-in/check-out.
• CVS (Concurrent Versioning System) is built on
  top of RCS and implements a concurrent access
  scheme.
• Subversion is a newer and is designed as a
  replacement for CVS. It is more easily deployed
  as a server. It is rapidly displacing CVS as the
  version control system of choice.
• Visual Source Safe is part of Microsoft Visual
  Studio. It is a check-in/check-out system and
  only runs on Windows.
• There are other open source and commercial
  implementations available.

5
Subversion

• Runs on Linux, Unix, MacOS, and Windows.
• Files, properties, and versioning information is
  maintained in a repository.
• The developer works with a copy located in a
  local working directory.
• Subversion repositories are local or
  server-based.
• The URL of the repository describes the access
  method
• file//... a local file based repository
• svn// - a repository using the built-in
  svnserver
• svnssh// - an svnserver with ssh used to
  control access (not a tunnel)
• http//... a web based repository, most common
  in multi user environments
• http//subversion.tigris.org/ home page
• http//svnbook.red-bean.com/ Subversion Book

6
Subversion

• URL Notes
• When using the file// method, do not use it in
  multi user mode while the repository is located
  on a shared network disk. It is unreliable and
  will eventually corrupt your repository.
• When using the http// method, you can view the
  current head revision files using a normal
  browser.

7
Subversion
8
Subversion

• Plain SVN is a line mode system.
• ex, svn update
• There are several GUI clients
• http//subversion.tigris.org/links.html
• TortoiseSVN is popular Windows client, explorer
  extension
• Download TortoiseSVN from
• http//tortoisesvn.tigris.org/

9
Subversion

• Installation of TortoiseSVN
• Download TortoiseSVN from
• http//tortoisesvn.tigris.org/
• Double click file
• TortoiseSVN-1.5.3.13783-win32-svn-1.5.2.msi
• Installs as an explorer extension
• special file icons for affected files
• added right-click menu items
• Start Programs TortoiseSVN
• Includes a differences program
• After installation explorer or computer must be
  restarted.

10
Subversion

• Use Cases
• create a repository
• import initial files into new repository
• check out a repository into a working directory
• update a working directory
• change file svn properties
• add a new file to a repository
• commit changes to the repository
• checking status of files in working set
• listing files in repository
• show a files log entries
• revert to a previous version
• resolving conflicts

11
Subversion

• Create a Local Repository

12
Subversion

• Create a pair of directories/folders.
• work is the working directory.
• repos is the directory where repositories will
  reside.

13
Subversion

• Create the specific repository directory.
• Use the TortiseSVN Explorer extension, right
  click the mouse on the repos folder.

14
Subversion

• A dialog box will appear asking for the type of
  repository to create. The choice is either a
  Berkeley Database file or a file-based
  repository. In most cases the file-based
  repository is best.
• The line-mode equivalent is
• svnadmin create proj1 fs-type fsfs

15
Subversion

• Now the repos directory is filled with folders
  and files that are used by Subversion to manage
  the repository.
• The repository is still empty.

16
Subversion

• Import Project Files to Repository

17
Subversion

• The initial set of files that are to be placed
  under version control are created in the work
  directory. In this example a single file,
  matmult.c, is created.
• This is an optional step. It is used only if
  there is an existing project that is being added
  to a repository.
• See slides on Adding Files to repository.

18
Subversion

• The next slide shows the contents of matmult.c.
• In particular see line 5. The string Id
  identifies the revision number associated with
  the file. This string is updated to show the
  version id every time the working file is
  updated, if the appropriate property is set.

19
Subversion
t1 clock() for(iter0iterlt10iter)
for(i0iltMAXi) for(j0jltMAXj)
cij 0.0 for(k0kltMAXk)
cij cij aik
bkj t2
clock() printf("t1d, t2d\n",t1,t2)
printf("cpu time8.3f\n",(float)(t2 -
t1)/CLOCKS_PER_SEC) / printmat(c,MAX,MAX)
/

• include ltstdio.hgt
• include lttime.hgt
• define MAX 500
• static char svnid "Id "
• void printmat(double a,int imax, int jmax)
• long int i,j
• printf("enter printmat\n")
• for (i0iltimaxi)
• for (j0jltjmaxj)
• printf("5.2f ",(a (jmax i) j))
• printf("\n")

20
Subversion

• The next step is to import the initial set of
  files into the repository.
• Right-click the mouse on the work directory.

21
Subversion

• This dialog box requests the location of the
  repository. It is entered as a URL.
• In this case the repository is a local directory
  so use the file// form.
• A web based URL might be http//svn/svn/proj

22
Subversion

• This is the result of the import operation. It
  shows that one file has been added to the
  repository.
• The current revision number is 1.

23
Subversion

• The contents of the work directory can now be
  discarded.

24
Subversion

• Check Out the Repository to a Working Directory

25
Subversion

• Create a subversion working directory under
  revision control.
• We will reuse the work directory.
• To do this delete the contents of the work
  directory. At least the files that were added to
  the repository.
• Now checkout the contents of the repository to
  the work directory.

26
Subversion

• This dialog box is used to control what is
  checked out and to where.
• The directory work will be created if it does not
  exist.

27
Subversion

• For a server based working directory, the file
  work usually has the same name as the repository.

28
Subversion

• This dialog box lists the files that were added
  to the working directory.

29
Subversion

• Opening the working directory.
• The TortoiseSVN extension results in changes to
  the file icons.

30
Subversion

• Additional information about revision controlled
  files can be displayed by using View/Details and
  then View/Choose Details

31
Subversion

• The dialog box that results from View/Choose
  Details
• The SVN parameters, if selected, will be
  displayed when View/Details is selected as the
  directory format.

32
Subversion

• The result of selecting SVN Revision and SVN
  Status.

33
Subversion

• Update a Working Directory

34
Subversion

• Right click on directory or file and select SVN
  Update.
• This will load the current version from the
  repository to the working directory.
• When using a multi user repository it is a good
  idea to execute an update before working on the
  file.

35
Subversion

• Set Subversion Properties

36
Subversion

• To set properties on svn controlled files

37
Subversion

• To set properties on svn controlled files.

38
Subversion

• To set properties on svn controlled files.
• The drop-down box shows the available properties.

39
Subversion

• svneol-style
• Subversion will set the end-of-line in a text
  file appropriate to the destination working
  directory.
• svnkeywords
• Informs Subversion to handle the keywords, eg,
  Id , which will be updated when downloaded to
  the working directory.
• svnexecutable
• Informs Subversion that the file is an executable
  file. It will set permissions on the working
  copy to allow execution.

40
Subversion

• For this file svnkeywords has been set to Id and
  svneol-style has been set to native.

41
Subversion

• Going back an looking at the work directory
  notice that the icon for the file matmult.c has
  changed. In this case it indicates that the svn
  properties for the file have changed.

42
Subversion

• Add a New File to a Working Directory

43
Subversion

• To add a new file, readme.txt, to the repository.
  Create the file in the working directory, then
  use svn add

44
Subversion

• The dialog box that lists the files to be added
  to the repository. And the result of the add
  operation.

45
Subversion

• The freshly added file has a icon to indicate
  its status. Now set the properties of the file
  then commit it.

46
Subversion

• The status of the working directory after the
  commit operation. Note that readme.txt is level
  3 and matmult.c is level 2.

47
Subversion

• Adding is the better way to put files into a
  repository.
• Create the file in the working directory.
• Add the file to the repository.
• Set the appropriate properties.
• Commit the file to the repository.

48
Subversion

• Commit Changes to Repository

49
Subversion

• Now commit the changed file to the repository.

50
Subversion

• The dialog that results from the commit operation
  allows you to enter a log message that describes
  the changes made.

51
Subversion

• The final dialog box verifying the update of the
  repository. The revision number is now 2. The
  icon for matmult.c reverts to the green check.
  Looking at the file matmult.c shows the
  following
• static char svnid "Id matmult.c 2
  2006-11-08 153316Z latham "

52
Subversion

• Listing the Contents of the Repository

53
Subversion

• The contents of the repository can be viewed by
  using the repository browser.

54
Subversion

• The list of files in the repository.

55
Subversion

• Show Log for File

56
Subversion

• To show a files log entries, right click the file
  and select TortoiseSVN Show Log.
• The window at the right shows every revision made
  that included a comment.
• Use TortoiseSVN Revision Graph for a complete
  list of all revisions.

57
Subversion

• Revert to a Previous Version

58
Subversion

• Right click on the file to revert, then select
  the revision number that you want.

59
Subversion

• Resolving Conflicts
• (todo)